Fundamentals of mapping in the software package Surfer.

Ministry of Education and Science Russian Federation

COURSE WORK

Construction of digital elevation models based on SRTM radar topographic survey data

Saratov 2011

Introduction

The concept of digital elevation models (DEM)

1 The history of the creation of the DEM

2 Types of DEM

3 Ways and methods for creating a DEM

4 National and global DEMs

Radar Topographic Survey Data (SRTM)

1 Versions and data nomenclature

2 Accuracy assessment of SRTM data

3 Using SRTM data to solve applied problems

The use of SRTM in the creation of geo-images (on the example of the Saratov and Engel districts)

1 The concept of geoimaging

2 Building a digital elevation model for the territory of the Saratov and Engel districts

Conclusion

Introduction

Digital elevation models (DEMs) are one of the important modeling functions of geographic information systems, including two groups of operations, the first of which serves the solution of the problems of creating a relief model, the second - its use.

This type The product is a fully three-dimensional display of the real terrain at the time of surveying, which allows it to be used to solve various applied problems, for example: determining any geometric parameters of the relief, building cross-sectional profiles; carrying out design and survey work; monitoring of terrain dynamics; calculation of geometric characteristics (area, length, perimeter) taking into account the relief for the needs of architecture and urban planning; engineering surveys, cartography, navigation; calculation of slope steepness, monitoring and forecasting of geological and hydrological processes; calculation of illumination and wind regime for architecture and urban planning, engineering surveys, environmental monitoring; construction of visibility zones for telecommunication and cellular companies, architecture and urban planning. In addition, DEMs are widely used for visualization of the territory in the form of three-dimensional images, thereby providing an opportunity to build virtual terrain models (VTMs).

Relevance of the topic term paper is due to the need for geographical research in the use of digital relief data due to the growing role of geoinformation technologies in solving various problems, the need to improve the quality and efficiency of methods for creating and using digital elevation models (DTM), ensuring the reliability of the created models.

Topographic maps, remote sensing data (RSD), data from satellite positioning systems, geodetic works serve as traditional sources of initial data for creating a land DEM; measurements and echo sounding data, materials from phototheodolite and radar surveys.

Currently, in some developed countries, national DEMs have been created, for example, for the territory of the USA, Canada, Denmark, Israel and other countries. There are currently no publicly available data of this quality on the territory of the Russian Federation.

An alternative source of elevation data is the freely distributed SRTM (Shuttle radar topographic mission) data, available over most of the globe with a model resolution of 90 m.

The aim of this work is to study alternative source altitude data - Earth radar imagery data - SRTM, as well as their processing methods.

Within the framework of the goal, it is necessary to solve the following tasks:

get theoretical ideas about the concept, types and methods of creating a DEM, study the necessary data for building a DEM, identify the most promising areas for using these models to solve various applied problems;

identify SRTM data sources, identify technical features, explore the possibilities of accessing SRTM data

show possible uses for this type of data.

For writing a term paper, the following sources were used as sources: study guides on geoinformatics and remote sensing, periodicals, electronic resources of the Internet.

1. The concept of digital elevation models (DEM)

One of the significant advantages of geographic information systems technologies over conventional "paper" cartographic methods is the ability to create spatial models in three dimensions. The main coordinates for such GIS models, in addition to the usual latitude and longitude, will also be altitude data. At the same time, the system can work with tens and hundreds of thousands of elevation marks, and not with units and tens, which was also possible when using “paper” cartography methods. In connection with the availability of fast computer processing of huge arrays of high-altitude data, the task of creating the most realistic digital elevation model (DEM) becomes realistic.

A digital elevation model is commonly understood as a means of digital representation of three-dimensional spatial objects (surfaces, or reliefs) in the form of three-dimensional data, forming a set of height marks (depth marks) and other values ​​of the Z coordinate, at the nodes of a regular or continuous network, or a set of contour lines records (isohyps, isobaths) or other isolines. DEM is a special kind of three-dimensional mathematical models representing the relief of both real and abstract surfaces.

1 The history of the creation of the DEM

The image of the relief has long interested people. On the oldest maps, large landforms were displayed as an integral part of the landscape and as an element of orientation. The first way to display relief was by perspective signs showing mountains and hills; however, since the eighteenth century, active development of new, increasingly complex methods began. A promising method with a dashed drawing is presented on a map of the Pyrenees (1730). Color for relief plastics was first used in the Atlas of the campaign of Russian troops in Switzerland (1799). The first experiments on the creation of a DEM date back to the earliest stages of the development of geoinformatics and automated cartography in the first half of the 1960s. One of the first digital terrain models was made in 1961 at the Department of Cartography of the Military Engineering Academy. Subsequently, methods and algorithms for solving various problems were developed, powerful software modeling, large national and global relief data arrays, experience has been gained in solving various scientific and applied problems with their help. In particular, the use of DEM for military tasks has received great development.

2 Types of DEM

The most widely used surface representations in GIS are raster representation and TIN models. Based on these two representatives, historically two alternative models DTMs: based on purely regular (matrix) representations of the relief field with height marks and structural, one of the most developed forms of which are models based on a structural-linguistic representation.

Raster relief model - provides for the division of space into further indivisible elements (pixels), forming a matrix of heights - a regular network of elevation marks. Similar digital elevation models are created by the national mapping services of many countries. A regular grid of heights is a grid of equal rectangles or squares, where the vertices of these shapes are grid nodes (Figure 1-3).

Rice. 1.2.1 An enlarged fragment of the terrain model showing the raster structure of the model.

Rice. 1.2.2 Displaying a regular elevation network model on a plane.

Rice. 1.2.3. Three-dimensional model of the relief of the surroundings of the village. Kommunar (Khakassia), built on the basis of a regular network of heights /1/

One of the first software packages that implemented the possibility of multiple input of different layers of raster cells was the GRID package (translated from English - lattice, grid, network), created in the late 1960s. at the Harvard Laboratory for Computer Graphics and Spatial Analysis (USA). In the modern widespread ArcGIS GIS package, the raster spatial data model is also called GRID. In another popular program for DEM calculation - Surfer, the regular grid of heights is also called GRID, the files of such a DEM are in the GRD format, and the calculation of such a model is called Gridding.

When creating a regular height grid (GRID), it is very important to take into account the density of the grid (grid step), which determines its spatial resolution. The smaller the selected step, the more accurate the DTM - the higher the spatial resolution of the model, but the greater the number of grid nodes, therefore, more time is required to calculate the DEM and more disk space. For example, if the grid step is reduced by 2 times, the volume computer memory required to store the model increases by a factor of 4. It follows that a balance must be found. For example, the US Geological Survey DEM standard, developed for the National Digital Mapping Databank, specifies a digital elevation model as a regular array of elevations at 30x30 m grid nodes for a 1:24,000 scale map. By interpolation, approximation, smoothing, and other transformations to raster model, DEMs of all other types can be given.

Among the irregular meshes, the most commonly used triangular irregular mesh is the TIN model. It was developed in the early 1970s. as a simple way to build surfaces based on a set of irregularly spaced points. In the 1970s several variants of this system were created, commercial systems based on TIN began to appear in the 1980s. as software packages for constructing contour lines. The TIN model is used for digital terrain modeling, while the nodes and edges of the triangular network correspond to the original and derived attributes of the digital model. When building a TIN model, discretely located points are connected by lines forming triangles (Fig. 4).

Rice. 1.2.4. Delaunay triangulation condition.

Within each triangle of a TIN model, the surface is typically represented by a plane. Since the surface of each triangle is given by the heights of its three vertices, the use of triangles ensures that each section of the tiled surface fits exactly to adjacent sections.

Fig.1.2.5. Three-dimensional terrain model built on the basis of an irregular triangulation network (TIN).

This ensures the continuity of the surface with an irregular arrangement of points (Fig. 5-6).

Rice. 1.2.6. An enlarged fragment of the relief model in fig. 5 showing the triangular structure of the TIN model.

The main method for calculating TIN is Delaunay triangulation. in comparison with other methods, it has the most suitable properties for a digital elevation model: it has the lowest harmonicity index as the sum of the harmonicity indices of each of the generating triangles (proximity to equiangular triangulation), the properties of the maximum of the minimum angle (the greatest non-degeneracy of triangles) and the minimum of the area of ​​the formed polyhedral surface.

Since both the GRID model and the TIN model have become widespread in geographic information systems and are supported by many types of GIS software, it is necessary to know the advantages and disadvantages of each model in order to choose the right format for storing elevation data. As advantages of the GRID model, it should be noted the simplicity and speed of its computer processing, which is associated with the very raster nature of the model. Output devices such as monitors, printers, plotters, etc. use sets of points to create images, i.e. are also in raster format. Therefore, GRID images are easily and quickly output to such devices, since it is easy for computers to calculate to represent individual squares of a regular network of heights using points or video pixels of output devices.

Due to its raster structure, the GRID model allows you to "smooth" the simulated surface and avoid sharp edges and protrusions. But this is also the “minus” of the model, because when modeling the relief of mountainous regions (especially young ones - for example, alpine folding) with an abundance of steep slopes and pointed peaks, the loss and “blurring” of the structural lines of the relief and the distortion of the overall picture are possible. In such cases, an increase in the spatial resolution of the model (elevation grid step) is required, and this is fraught with a sharp increase in the amount of computer memory required to store the DEM. In general, GRID models tend to take up more disk space than TIN models. To speed up the display of large-scale digital elevation models, various methods are used, of which the most popular is the construction of the so-called pyramidal layers, which allow, at different scales, to use various levels image detail. Thus, the GRID model is ideal for displaying geographical (geological) objects or phenomena, the characteristics of which smoothly change in space (flat terrain, air temperature, atmospheric pressure, oil reservoir pressure, etc.). As noted above, the shortcomings of the GRID model appear when modeling the relief of young mountain formations. A particularly unfavorable situation with the use of a regular network of height marks develops if vast leveled areas alternate with areas of ledges and cliffs with sharp elevation changes in the modeled area, as, for example, in the wide developed valleys of large flat rivers (Fig. 7). In this case, there will be “redundancy” of information on most of the modeled territory, since GRID grid nodes in flat areas will have the same height values. But in areas of steep relief ledges, the height grid step size may turn out to be too large, and, accordingly, the spatial resolution of the model is insufficient to convey the “plasticity” of the relief.

Rice. 1.2.7. A fragment of a three-dimensional relief model of the Tom valley (the red arrow shows the ledge of the second floodplain terrace on the left bank, the high ledge on the right bank is the slope of the interfluve plain). The vertical scale is five times larger than the horizontal scale.

The TIN model does not have such shortcomings. Since an irregular network of triangles is used, flat areas are modeled by a small number of huge triangles, and in areas of steep ledges, where it is necessary to show in detail all the facets of the relief, the surface is displayed by numerous small triangles (Fig. 8). This allows you to more efficiently use the resources of the computer's RAM and permanent memory to store the model.

Rice. 1.2.8. Irregular network of triangles.

Among the "minuses" of TIN should be attributed the high cost of computer resources for processing the model, which significantly slows down the display of the DEM on the monitor screen and printing, because. this requires rasterization. One solution to this problem could be the introduction of "hybrid" models that combine TIN breaklines and a way to display as a regular set of points. Another significant drawback of the TIN model is the “terrace effect”, which is expressed in the appearance of so-called “pseudo-triangles” - flat areas in an obviously impossible geomorphological situation (for example, along the bottom line of V-shaped valleys) (Fig. 9).

One of the main reasons is the small distance between the points of digital recording of contour lines in comparison with the distances between the contour lines themselves, which is typical for most types of relief in their cartographic display.

Rice. 1.2.9. "Effect of terraces" in the valleys of small rivers, which occurs when creating a TIN based on contour lines without taking into account the structural lines of the relief (in this case, hydro networks).

3 Ways and methods for creating a DEM

Since the first maps appeared, cartographers have faced the problem of displaying three-dimensional relief on a two-dimensional map. Various methods have been tried for this. On the topographic maps ah and plans, the relief was depicted with the help of horizontal lines - lines of equal heights. Hillshading (hatching) of the relief was given on general geographical and physical maps, or a color of the corresponding tonality (height scale) was assigned to a certain height of the terrain. At present, with the advent of digital maps and plans, an increase in performance computer technology there are new possibilities for representing the terrain. Three-dimensional visualization of the relief model is becoming increasingly popular, as it enables even professionally unprepared people to get a fairly complete picture of the relief. Modern technologies three-dimensional visualization allows you to "look" at the terrain from any point in space, at any angle, as well as "fly" over the terrain.

Since the development of information systems and technologies, as well as the development of the satellite industry, various methods and methods have appeared that make it possible to build a DEM. There are two fundamentally different ways of obtaining data for building digital elevation models.

The first way is remote sensing methods and photogrammetry. Such methods for creating a DEM include the method of radar interferometry. It is based on the use of the phase component of the radar signal reflected from the Earth's surface. The accuracy of DEM reconstruction by the interferometric method is a few meters, and it varies depending on the nature of the terrain and the level of signal noise. For a smooth surface and for a high quality interferogram, the relief reconstruction accuracy can reach several tens of centimeters. There is also a method of stereoscopic processing of radar data. For the module to work, it is necessary to have two radar images taken with different beam tilt angles. The accuracy of DEM reconstruction by the stereoscopic method depends on the size of the image spatial resolution element. Aerial laser scanning technology (ALS) is the fastest, complete and reliable way to collect spatial and geometric information about hard-to-reach (boggy and forested) territories. The method provides accurate and detailed data on both the relief and the situation. Today, VLS technology makes it possible in the shortest possible time to obtain complete spatial and geometric information about the terrain, vegetation cover, hydrography and all ground objects in the survey strip.

The second way is to build elevation models by interpolating digital contour lines from topographic maps. This approach is also not new and has its strengths and weaknesses. Among the shortcomings can be called the complexity and sometimes insufficiently satisfactory accuracy of modeling. But, despite these shortcomings, it can be argued that digitized topographic materials will be uncontested sources of data for such modeling for several more years.

4 National and global DEMs

The general availability of data and DEM construction technologies enable many countries to create national elevation models used for the country's personal needs, examples of such countries are the USA, Canada, Israel, Denmark and some other countries. The United States is one of the leaders in the creation and use of DEMs. Currently, the country's national topographic and mapping service - the U.S. Geological Survey - produces five data sets representing DEM in the DEM (Digital Elevation Model) format and differing in technology, resolution and spatial coverage. Another example of a successful national FEM experience is the Danish FEM. The first digital terrain model of Denmark was created in 1985 to solve the problem of optimal placement of mobile network translators. Digital elevation models in the form of elevation matrices are part of the basic spatial data sets of almost all national and regional SDIs (information spatial data). At the current level of technology development, the grid spacing of elevations in national DEMs reaches 5 m. DEMs with a similar spatial resolution are completely ready or will be ready in the near future for such large territories as the European Union and the United States. The expediency of the restriction on the detail of the relief established in our country is lost in conditions when it is possible to purchase a freely distributed global ASTGTM DEM with an elevation grid step of about 30 m (one arc second) on the world market. In addition, the resolution of publicly available DTMs is expected to steadily increase. As a possible temporary solution to the problem, it is proposed to keep the most detailed basic DEM secret and freely distribute less detailed DEMs created on the basis of the basic one; gradually reduce the DEM secrecy threshold depending on the accuracy of the relief representation and the area of ​​the area covered by it.

2. SRTM data

radar topographic mission (SRTM) - Radar topographic survey of most of the globe, except for the northernmost (>60), southernmost latitudes (>54), and the oceans, made over 11 days in February 2000 using a special radar system, from the space shuttle "Shuttle". Two radar sensors SIR-C and X-SAR collected more than 12 terabytes of data. During this time, using a technique called radar interferometry, great amount information about the Earth's relief, its processing is still ongoing. The result of the survey was a digital relief model of 85 percent of the Earth's surface (Fig. 9). But a certain amount of information is already available to users. SRTM- international project, led by the National Geospatial Intelligence Agency (NGA), NASA, the Italian Space Agency (ASI) and the German Space Center.

Rice. 2.1. Scheme of coverage of the Earth's territory by SRTM survey.

1 Versions and data nomenclature

The SRTM data exists in several versions: preliminary (version 1, 2003) and final (version 2, February 2005). The final version went through additional processing, highlighting coastlines and water bodies, filtering out erroneous values. The data is distributed in several versions - a grid with a cell size of 1 arc second and 3 arc seconds. More accurate one-second data (SRTM1) is available for the US, only three-second data (SRTM3) is available for the rest of the earth. The data files are a matrix of 1201 ´ 1201 (or 3601 ´ 3601 for the one-second version) of values ​​that can be imported into various mapping programs and geographic information systems. In addition, there is version 3 distributed as ARC GRID files, as well as ARC ASCII and Geotiff format, 5 squares ´ 5 in the WGS84 datum. These data were obtained by CIAT from original USGS/NASA elevation data through processing that produced smooth topographic surfaces as well as interpolation of areas where the original data were missing.

The data nomenclature is produced in such a way that the name of the data square of versions 1 and 2 corresponds to the coordinates of its lower left corner, for example: N45E136, where N45 is 45 degrees north latitude and E136 is 136 degrees east longitude, the letters (n) and (e) in the name file designate, respectively, the northern and eastern hemispheres. The name of the square of the data of the processed version (CGIAR) corresponds to the number of the square at the rate of 72 horizontal squares (360/5) and 24 vertical squares (120/5). For example: srtm_72_02.zip /far right, one of the top squares. You can determine the desired square using the grid layout (Fig. 11.).

Fig.2.1.1. SRTM4 coverage scheme.

2 Accuracy assessment of SRTM data

Height values ​​in the corners of a cell measuring 3 by 3 are publicly available. The height accuracy is declared to be no lower than 16 m, but the type of estimation of this value - the average, maximum, root mean square error (RMS) - is not explained, which is not surprising, since for a rigorous assessment of accuracy either reference height values ​​of approximately the same degree of coverage are needed, or a rigorous theoretical analysis of the process of obtaining and processing data. In this regard, the analysis of the accuracy of the SRTM DEM was carried out by more than one team of scientists from around the world. According to A.K. Korvaula and I. Eviak of the SRTM heights have an error, which averages 2.9 m for flat terrain, and 5.4 m for hilly terrain. Moreover, a significant part of these errors includes a systematic component. According to their conclusions, the SRTM DEM is suitable for constructing contour lines on topographic maps at a scale of 1:50000. But in some areas, the SRTM heights approximately correspond in their accuracy to the heights obtained from a topographic map at a scale of 1:100000, and can also be used when creating orthomosaics from satellite images. high resolution taken with a slight deviation from nadir.

2.3 Using SRTM data to solve applied problems

SRTM data can be used in various applications, of varying degrees of complexity, for example: for using them in the construction of orthophotomaps, for assessing the complexity of upcoming topographic and geodetic works, planning their implementation, and can also assist in designing the location of profiles and other objects even before carrying out topographic surveys, obtained from the results of the SRTM radar survey, the values ​​of elevations of terrain points can be used to update the topographic base of territories where there are no data from detailed topographic and geodetic works. This type of data is a universal source for earth modeling, mainly for the construction of digital elevation models and digital terrain models, but the question of the applicability of SRTM radar height data as an alternative standard methods building a digital terrain and relief model, in our opinion, should be decided in each case individually, depending on the task, the characteristics of the relief and the required accuracy of the height reference .

3. Application of SRTM in the creation of geoimaging

1 The concept of geoimaging

Progress in geoinformation mapping, remote sensing and means of understanding the world around. Shooting at any scale and range, with different spatial coverage and resolution, is carried out on the ground and underground, on the surface of the oceans and under water, from the air and from space. The whole set of maps, images and other similar models can be designated by one general term - geoimaging.

A geoimage is any spatio-temporal, large-scale, generalized model of terrestrial or planetary objects or processes, presented in a graphic figurative form.

Geo-images represent the bowels of the Earth and its surface, oceans and atmosphere, pedosphere, socio-economic sphere and areas of their interaction.

Geoimages are divided into three classes:

Flat, or two-dimensional, - maps, plans, anamorphoses, photographs, photographic plans, television, scanner, radar and other remote images.

Volumetric, or three-dimensional, - anaglyphs, relief and physiographic maps, stereoscopic, block, holographic models.

Dynamic three and four-dimensional - animations, cartographic, stereo-cartographic films, film atlases, virtual images.

Many of them have entered into practice, others have appeared recently, and others are still under development. So in this course work, we built two-dimensional and three-dimensional geoimages.

3.2 Building a digital elevation model for the territory of the Saratov

and Engelsky district

First, download the public SRTM data of additional processing version 2, on the Internet portal open to any network user (#"justify"> In the future, open the downloaded fragment in the Global Mapper program, select the "File" function, then "Export Raster and Elevation Data" - " Export Dem” (Fig. 12), this series of operations was done in order to convert the downloaded data into the DEM format, which is readable by the Vertical Mapper program, in which the model will be built.

Fig.3.2.1. Export the file to DEM format, in the Global Mapper program [done by the author].

After exporting the data, open the Vertical Mapper program, in which we produce further actions- Create Grid - Import Grid (Fig.13).

Rice. 3.2.2. Creation of Grid - model in the program Vertical Mapper [performed by the author].

With the help of these functions, we create a GRID model with which the author later carried out all operations to create a DEM for the territory of the Saratov region, to create contour lines and a three-dimensional terrain model.

Conclusion

The digital elevation model is an important modeling function in geographic information systems, as it makes it possible to solve the problems of constructing a relief model and its use. This type of product is a fully three-dimensional display of the real terrain at the time of surveying, thereby making it possible to solve a variety of applied tasks: determining any geometric parameters of the relief, building cross-sectional profiles; carrying out design and survey work; monitoring of terrain dynamics. In addition, DEMs are widely used for visualization of the territory in the form of three-dimensional images, thereby providing an opportunity to build virtual terrain models (VTMs).

The relevance of the topic of the course work is due to the wide need for geographic studies of digital relief data, due to the growing role of geoinformation technologies in solving various problems, the need to improve the quality and efficiency of methods for creating and using digital elevation models (DTM), ensuring the reliability of the created models.

Currently, there are several main sources of data for building digital elevation models - this is by interpolation of digitized isolines from topographic maps and the method of remote sensing and photogrammetry. The remote sensing method is gaining more and more strength in solving many geographical problems, such as building a relief based on satellite radar sounding of the Earth. One of the products of Earth radar sounding is the publicly available and freely distributed SRTM (Shuttle radar topographic mission) data, available for most of the globe with a model resolution of 90 m.

In the process of writing a term paper, a digital elevation model was built for the territory of the Saratov and Engelsky regions, thereby solving the tasks of construction and proving the possibility of creating a DEM based on SRTM data.

relief digital radar geoimaging

List of sources used

1. Khromykh V.V., Khromykh O.V. Digital elevation models. Tomsk: TML-Press Publishing House LLC, signed for printing on 12/15/2007. Circulation 200 copies.

Ufimtsev G.F., Timofeev D.A. "Relief morphology". Moscow: Scientific world. 2004

B.A. Novakovsky, S.V. Prasolov, A.I. Prasolova. "Digital elevation models of real and abstract geofields". Moscow: Scientific world. 2003

A.S. Samardak "Geoinformation systems". Vladivostok FEGU, 2005 - 124p.

Geoprofi [ Electronic resource]: journal on geodesy, cartography and navigation / Moscow. - Electronic journal. - Access mode: #"justify">. Branches of application of GIS [Electronic resource]: database. - Access mode: #"justify">. Vishnevskaya E.A., Elobogeev A.V., Vysotsky E.M., Dobretsov E.N. United Institute of Geology, Geophysics and Minerology, Siberian Branch of the Russian Academy of Sciences, Novosibirsk. From materials international conference"Intercarto - 6" (Apatity, August 22-24, 2000).

GIS Association [Electronic resource]: database. - Access mode: #"justify">. GIS LAB Association [Electronic resource]: database. - Access mode: #"justify">10. Jarvis A., H.I. Reuter, A. Nelson, E. Guevara, 2006, Hole-filled seamless SRTM data V3, International Center for Tropical Agriculture (CIAT)

11. A. M. Berlyant, A.V. Vostokova, V.I. Kravtsova, I.K. Lurie, T.G. Svatkova, B.B. Serapinas "Cartology". Moscow: Aspect Press, 2003 - 477 p.

Mikhail Vladimirovich Morozov:
personal site

Mathematical models (lesson, map-1): Construction of geochemical maps in Golden Software Surfer (general approach, stages and content of the work, report form)

Well " Mathematical modeling methods in geology"

Maps-1. Construction of geochemical maps in Golden Software Surfer: general approach, stages and content of the work. Report form.
Maps-2. Principles of working with Golden Software Surfer.

To find the place of accumulation of useful metal in the earth's crust, a geochemical map is required. How to build it? This requires good software and a systematic approach. Let's get acquainted with the principles and main stages of this work.

THEORY

Construction of a geochemical map in the Golden Software Surfer program.

Initial data. To build a geochemical map, it is necessary to prepare spreadsheet, which contains at least three columns: the first two contain the geographical coordinates of the observation (sampling) points X and Y, the third column contains the mapped value, for example, the content of a chemical element.

Coordinates: in the Surfer program we use rectangular coordinates (in meters), although in the map properties you can also choose among the possible coordinate systems various polar coordinates (in degrees-minutes-seconds). In practice, when working with images on a flat sheet of paper, it is more convenient to work in a rectangular coordinate system in a custom format.

Where do the coordinates come from:
1. When documenting a point in place, the coordinates are taken from the GPS or GLONASS topographic location in the form of polar coordinates (for example, in the coordinate system WGS 84). A topographic surveyor may now look like a smartphone, but it is more convenient and reliable to use a special device, which is affectionately called a "jeepies".
2. When transferring data to a computer from a topographic location, the coordinates are converted from polar to the used system of rectangular coordinates (for example, in systems UTM, Pulkovo-1942, but you can also use local geodetic system adopted at a particular enterprise). To convert polar coordinates to rectangular it is convenient to use the program Ozi Explorer.
3. The columns of the spreadsheet prepared for working with Surfer should contain rectangular coordinates in meters.

Mapped value: to build a training map in contour lines, we will use content logarithm any chemical element. Why logarithm? Because the law of distribution of trace elements is almost always logarithmic. Of course, in real work, you first need to check the distribution law in order to choose the type of quantity: the original value or its logarithm.

Types of maps used in geochemistry. In addition to the contour map, geochemists often use some other types of maps, but not all the great variety of types of maps that Surfer can build, but only strictly defined ones. They are listed below.

1. Map of facts. It is a set of points showing the sampling sites on the ground. Labels can be displayed near the points - picket numbers, but during geochemical searches there are so many points that usually the labels only "clog" the map space and are not given. To build a fact map, we use the function Post Map.

2. Dot map of the abundances of a chemical element. On it, circles (or other symbols) of different sizes indicate different contents of a chemical element at sampling points. If we use such a map, then a separate fact map is no longer needed - the points of both maps will overlap each other. A dot map (or "post map") is constructed in such a way that high contents of the desired element are conspicuous. The legend indicates the correspondence between the circle size and the content of the element in g/t. In addition to the size, the color of the circle can change. Each type (size, color) of a mug corresponds to a manually assigned content range. Those. different types circles are different classes of points according to the content of the element. Therefore, the tool for creating such a map is called Classed Post Map. It is convenient to build a posting map on top of the contour map in order to see how the latter (which is a calculated map, i.e. built from the results of data interpolation) is combined with the original ones obtained from the laboratory, i.e. "true" content. It is convenient to place the posting of one important element (for example, gold) on the map in the contour lines of another search parameter (satellite element, statistical factor, geophysical parameter, etc.). Important: after construction, a map of type Classed Post Map cannot be converted to Post Map, vice versa is also impossible.

3. Map in isolines. Actually the map of the desired parameter, where different gradations of contents are displayed with different color fills. Also requires a legend that associates the fill color with the grade level. Fill gradations are adjusted manually. Tool - Contour Map. In addition to the elemental abundances themselves (or their logarithms), maps of multielement indicators are widely used in geochemistry. These can be multiplicative coefficients (where the contents of several elements are multiplied), maps of factor (principal component) values, etc. Actually, the task of a geochemist is to find an indicator that allows solving a geological problem. Since such indicators, as a rule, are expressed in the collective behavior of elements, it is quite natural that single-element maps (i.e., maps of one individual element) are often less informative than multi-element maps. Therefore, the stage of building maps is usually preceded by the stage of statistical data processing with the results of multivariate statistical analysis, for example, PCA (principal component method).

4. Map stroke. Surfer creates a rectangular map by default. If the sampling points do not form a rectangle, it turns out that the sampling area is inscribed in an artificially created rectangle in which part of the area was not actually sampled. The contour map will be built over the entire area, so unsampled areas of the map will contain fictitious data. To avoid this, it is necessary to limit the map construction area to that part of the area for which sampling data are available. To do this, the sampling area must be outlined with a special line, which can be built manually. The output of the stroke contour is carried out using the function base map.

Stages of building a map.

3. Building a map of facts [map-3]. 5. Construction of a point map ("posting map") [map-5]. 9. Construction of a surface map and its design to achieve optimal information content [Map-6, continued].

WORK PROCEDURE

Given: table of contents of a chemical element and its logarithms with coordinates of sampling points.

Exercise:

1. Build a map of facts.

2. Build a dot map based on the contents of the chemical element , select point mappings for different classes.

3. Independently create the contour of the mapping area and build it.

4. Align the area contour, element point map and fact map in the given order in the object manager. Display a legend for a point map.

5. Build a grid file ("grid") for the logarithms of element contents by triangulation method, check it. Repeat with other methods.

6. Build a variogram for building a grid file using the kriging method, check it.

7. Build a grid file ("grid") for the logarithms of the element grades by the kraiging method using the semivariogram parameters.

8. Smooth the resulting mesh file with a simple filter.

9. Restore grid file from logarithms to contents.

10. Cut the mesh file along the contour created earlier.

11. Build surface maps in isolines and gradient fill according to the created grid files, add legends.

12. Export the constructed maps as JPG files, insert into a report in Word (DOC) format.

Report form.

GEOLOGICAL SECTION

Geological section - a vertical section of the earth's crust from the surface to depth. Geological sections are compiled according to geological maps, data from geological observations and mine workings (including boreholes), geophysical surveys, etc. Geological sections are oriented mainly across or along the strike of geological structures along straight or broken lines passing in the presence of deep reference boreholes through these wells. Geological sections are influenced by the conditions of occurrence, age and composition of rocks. Horizontal and vertical scales of geological sections usually correspond to the scale of a geological map. When designing mining enterprises, engineering and geological surveys, due to the incomparability of the thickness of loose deposits and the length of profiles, their vertical scale is increased compared to the horizontal one by tens or more times.

SURFER IN GEOLOGY

The Golden Software Surfer geographic information system is currently the industry standard for plotting graphical representations of functions of two variables. There are few companies in the geological industry that do not use Surfer in their daily mapping practice. Especially often with the help of Surfer maps are created in isolines (contour maps).

The unsurpassed advantage of the program is the interpolation algorithms embedded in it, which allow you to create digital surface models with the highest quality from data that is unevenly distributed in space. The most commonly used method, Kriging, is ideal for representing data in all geosciences.

The logic of working with the package can be represented as three main functional blocks:

• · 1. Building a digital surface model;
• · 2. Auxiliary operations with digital surface models;
• · 3. Visualization of the surface.

A digital surface model is traditionally represented as values ​​in the nodes of a rectangular regular grid, the discreteness of which is determined depending on the specific problem being solved. To store these values, Surfer uses its own GRD (binary or text format), which have long become the standard for mathematical modeling packages.

There are three options for obtaining values ​​at grid nodes:

• 1) according to the initial data given at arbitrary points of the region (in the nodes of an irregular grid), using algorithms for interpolation of two-dimensional functions;
• · 2) calculation of the values ​​of the function specified by the user in an explicit form. The Surfer program includes a fairly wide range of functions - trigonometric, Bessel, exponential, statistical and some others;
• 3) transition from one regular grid to another, for example, when changing the discreteness of the grid (here, as a rule, rather simple interpolation and smoothing algorithms are used, since it is considered that the transition is performed from one smooth surface to another).

In addition, of course, you can use a ready-made digital surface model obtained by the user, for example, as a result of numerical simulation.

The Surfer package offers its users several interpolation algorithms: Kriging, Inverse Distance to a Power, Minimum Curvature, Radial Basis Functions, Polynomial Regression, Modified Method Shepard (Modified Shepard "s Method), Triangulation (Triangulation), etc. The calculation of a regular grid can be performed for X, Y, Z dataset files of any size, and the grid itself can have dimensions of 10,000 by 10,000 nodes.

Surfer uses the following types of maps as the main elements of the image:

• 1. Contour Map. In addition to the usual controls for displaying contours, axes, frames, markings, legends, etc., it is possible to create maps by filling individual zones with color or various patterns. In addition, the flat map image can be rotated and tilted, and independent scaling along the X and Y axes can be used.
• · 2. Three-dimensional image of the surface: Wireframe Map (wireframe map), Surface Map (three-dimensional surface). These cards use different types projection, while the image can be rotated and tilted using a simple GUI. You can also draw cut lines, isolines on them, set independent scaling along the X, Y, Z axes, fill individual grid elements of the surface with color or pattern.
• · 3. Maps of initial data (Post Map). These maps are used to display point data as special characters and text captions to them. At the same time, to display a numerical value at a point, you can control the size of the symbol (linear or quadratic dependence) or apply different symbols in accordance with the data range. One map can be built using several files.
• · 4. Map - base (Base Map). It can be almost any flat image obtained by importing files of various graphic formats: AutoCAD [.DXF], Windows Metafile [.WMF], Bitmap Graphics [.TIF], [.BMP], [.PCX], [.GIF ], [.JPG] and some others. These maps can be used not only to simply display an image, but also, for example, to display some areas as empty.

With the help of various overlay options for these main types of maps, their various placement on one page, you can get a variety of options for representing complex objects and processes. In particular, it is very easy to obtain various variants of complex maps with a combined image of the distribution of several parameters at once. All types of maps can be edited by the user using the built-in drawing tools of the Surfer itself.

Methodology for constructing structural maps of the roof (bottom) of an oil-bearing formation and its geological section.

• 1. Based on the file, build a base map on a scale of 1 cm 1000 meters.
• 2. Digitize the boundaries of the license area.
• 3. Digitize the wells and save the “roof” file in DAT format (column A - longitude, column B - latitude, column C - roof depth, column D - well number, column C - type of well: production with a three-digit number, the rest - exploration)
• 4. Digitize the profile line. Save in BLN format "profile line" with an empty cell B1.
• 5. Create an "Overview map of the licensed area" with layers - boundaries, profile line and wells with labels.
• 6. To the overview map add the layer "Structural map along the top of the YUS2 formation" - smoothed (with a coefficient of 3 for two coordinates), contour lines every 5 meters (Appendix 1).
• 7. Create a "Profile along the roof of the YUS2 formation" - the horizontal scale coincides with the map scale, the vertical scale is 1 cm 5 meters.

geological map profile software

Software package Surfer is designed for creating, editing, viewing, storing and modifying all types of maps and digital regular elevation grids. Software package Surfer consists of several independent subprograms, interconnected through the main program ( Plot Windows ) .

Worksheet Windows (Project window) - Project window contains workspace to create, view, edit, and save data files. Data can be generated in a questionnaire in a variety of ways. When creating a project window, you can load data files into notepad using the command open from the project file menu; you can directly enter data into the questionnaire, or use the window clipboard (Buffer) to copy data from another application and paste it into this one.

Editor Windows - The editor window contains a workspace for creating, viewing, editing, and saving ASCII text files. When the window is active, all necessary menus for working with ASCII text files are available.

Text created in the editor window can be copied and pasted into the drawing window (Plot Windows) . This allows you to create text blocks that can be saved to an ASCII text file and used on other cards, rather than having to recreate the text whenever it's needed to work. You can enter text into the editor window and save the file to disk. To use this text in a window Plot, you need to open text file in the editor window, copy the text to Buffer, and paste the text into the picture window.

Another function of the editor window is to calculate the volume on command Volume(Volume). When a volume is calculated, a new editor window is created with the results of the volume calculations. Volume calculation results can be copied to the window Plot or save as an ASCII text file.

To open the Editor window, select the command New from the menu file and select the option in the window Editor(Editor).

GS Script (GS Scripter) is the second independent program included in the package Surfer. GS script allows you to write macros to automate tasks in the program Surfer.

Program GS Scripter is like a translator that downloads and executes commands. The GS script is automatically installed when the program is installed Surfer, and has its own icon.

The GSscript consists of two windows. Window Editing is a standard Windows ASCII text editor that allows you to open, create, edit and save ASCII text files. Scripts run in the GS script window Editing. Second - day off the window is displayed only when called from the edit window.

Scripts are text files created in the editor window, Windows notepad, or any other ASCII editor. You can execute the script when the script file is displayed in the window GS script editing. The operations defined in the script will be executed. Scripts can contain commands necessary to automatically execute any OLE 2.0 program.

Plot Windows (Picture window) - The drawing window contains commands for creating and modifying elevation grid files, and for creating all types of maps. This is the main window of the program, so this chapter will most fully reflect the capabilities of this particular window.

The drawing window menu contains the following commands that allow you to create and edit various types of maps.

File (file) - Contains commands for opening and saving files, printing a map or surface, changing the print view, and opening new document windows.

New(New)- Creates a new document window. Team New creates a new window Plot (Picture) , Worksheet (Project) or editor. Keyboard shortcut: CTRL + N.

open(Open)- Opens an existing document. Team open searches for existing project files and displays them in a new drawing window. This makes the new window active. If the [.SRF] file has a data file of the same name, it will be loaded into the project under the same name. Surfer The [.SRF] file itself does not contain data, it only contains the name of the data file that is loaded when the map is created. If a [.SRF] file has been saved containing the name of a data file that no longer exists, an error message will be displayed when it is opened. The only file type that can be opened by the command open in the graphical menu window file, it's just a [.SRF] file. Other types of files open in other main menu items. The key combination CTRL + O.

close(Close)- Closes the active document window.

Save(Save)- Saves the active document. Team Save is used to save changes made to a [.SRF] file and leave the saved document displayed on the screen. When saving, the previous version of the file with the same name is replaced by this version. The key combination is CTRL+S.

Worksheet(Project)- Shows the project window. Team Worksheet opens a new empty project window. The project window is used to display, enter, or correct data. To display the data, you must first open an empty project window, and only then open an existing file by selecting the Open command from the Worksheet File menu.

Import(Import)- Imports borders, metafiles and bitmap files. Team Import like a team loadBaseMap except that the file is imported as a compound object rather than a map. Composite objects are made from various objects that have been grouped together into a single object. To split a compound object into its individual parts, you must use the command Break Apart. For example, when a file containing multiple polygons is imported (the file is originally a single feature made up of those multiple polygons), using the Break Apart command causes each polygon to become a separate feature. In this case, it becomes possible to change each polygon separately. Team Import can import files of any type on command loadBaseMap (Download basemap).

Export(Export)- Exports to various file formats. Team Export allows you to export a file in various formats for use by other programs. This allows you to create AutoCAD [.DXF], Windows Metafile [.WMF], Cut Buffer windows images[.CLP], or Computer Graphics Metafile [.CGM], as well as some raster formats. You can export the entire contents of the Drawing window, or select specific maps or features to export.

print(Seal)- Prints the active document on the installed printer. Keyboard shortcut: CTRL + P.

print Setup(Print Setting)- Shows a list of installed printers and allows you to select a printer.

Page layout(Strip layout)- Changes the dialing parameters. Teams Page Layout control the display of the page on the screen and the orientation of the picture on the page when printed. It sets the page size to match the paper size for the installed output device.

Options(Choice)- Managing feature display, selection, and page blocks.

Default Settings(Default commands)- Creates a set of [.SET] files that control the lack of display and grid setup. Team default settings allows you to load, modify, and save a set of [.SET] files. Surfer grids and displays "default" commands based on reading information in the [.SET] file. The set file contains a list of gridding, display, and general dialog box settings that are used during the session. Surfer.

Exit(Exit)- Exit from Surfer. Ends your session in the program Surfer.if part Surfer currently in the Clipboard, it is being converted to one of the standard Windows formats. Keyboard shortcut: F3, or ALT+F4.

Edit - Contains editing commands and commands that control object editing.

Undo- Deletes the last change made in the Drawing window. Undo can reverse multiple rate changes, allowing multiple steps to be copied. Keyboard shortcut CTRL+Z.

Redo (Redo)- Completely cancels the last command Undo. redo can completely undo several undo commands, allowing some steps to be redone.

Cut (Cut out)- Deletes the selected objects and places them in the Clipboard. This command is not available if nothing is selected. This erases the selected objects after copying them to the Clipboard. Later the content can be inserted with the command paste. Keyboard shortcut: CTRL+X or SHIFT+DELETE.

Copy (Copy)- Copies the selected objects to the Clipboard. This command is not available if nothing is selected. The original objects remain unchanged. This command can be used to duplicate objects for a different location in the same window, or in a different window, or for a different application. Only one data set can be placed in the Buffer, the following command Cut or Copy replaces the contents of the Buffer. Keyboard shortcut: CTRL+C or CTRL+INSERT.

paste (Insert)- Places a copy of the contents of the Clipboard in the active document window. This command is not available if the Cutout Buffer is empty. Keyboard shortcut: CTRL+V or SHIFT+INSERT.

paste Special(Special Paste)– Specifies the formats of the Cutout Buffer to use when pasting objects into the Drawing window. Four formats are available when pasting: GS Surfer, bitmap, picture or Text.

Format GS Surfer needed to paste objects copied from the graphics window Surfer. Format GS Surfer copies objects in their native format. For example, if a structure map is copied to the clipboard and pasted into another Drawing window in the format GS Surfer, the inserted structure map can be mounted and will be identical to the original in all respects.

Format Objects bitmap exist like rasters. Raster sizes are difficult to change without disturbing the image, and colors are also limited. This format is relatively common and is supported by most other Windows applications.

Format picture is a Windows metafile format where objects exist as a series of constituent Windows commands. Metafiles can be modified without the image being deformed. Format picture supported by most Windows applications.

Format Text uses import text. The imported text can contain any number of lines, and can include mathematical text commands. Imported text uses the default text value, assigning attributes using the command Text Attributes.

Delete(Erase)- Erases the selected objects. Team Delete removes all selected objects from the Drawing window, including any maps, parameters, drawings, or text. Team Delete does not affect the contents of the Cutout Buffer. Keyboard shortcut: DELETE.

Select All(Select all)- Selects all objects in the active window. It selects all objects on the page of the Drawing Window. Selection Markers 1 protrude around the outside of the group. Keyboard shortcut: F2.

block Select(Block Select)- Objects are selected within the specified rectangle. Team block select allows you to select all objects contained within a user-defined rectangle. The rectangle must completely surround objects, then only they will be selected. If this command is not selected, then all objects with any part of them falling within the bounding box 2 will be selected.

Flip Selections (Mirror selection)- Selects unselected objects, deselects selected objects. This command is useful for selecting a large number of objects and leaving a few isolated objects unselected.

Object ID (Object of identification)- Assigns an identification to the selected object. Team Object ID allows you to assign a name to any object type, including maps and map options. The assigned identification appears in the status bar when this object is selected.

Reshape(Restore original shape)- Modifies existing polygons or polylines. Restores the initial shape of the steps, new entries, and erases the vertex from the selected polyline or polygon. Each line segment in a polygon or polyline is defined by two vertices, each of which specifies the endpoints of the line segment. Team Reshape allows you to reshape a polygon or polyline by moving or erasing a vertex, and thus changing the line segments that define the polygon or polyline.

After selection Reshape, all vertices in the selected polygon or polyline are indicated by hollow squares. The selected vertex is indicated by a black square. The selected vertex can be moved by moving the mouse. To erase the selected vertex, press the DEL key. To paste a vertex, press the CTRL key, this will protrude a circle with crosshairs, which must be moved to the place where the vertex should be inserted.

color Palette(Color palette)- Allows you to change the color palette Surfer. Colors used in the program Surfer created by mixing different amounts of red, green and blue. Quantity Red, Green and blue colors are added to or subtracted from each of the colors as you wish when using the command Mix RGB. The color change is shown on the right in the type block. The range of color numbers is formed from 0 to 255. Editing window name changes the name used for the selected color, or the name of any traditional color that has been created. Button Append creates new entry created color at the end of the color palette. Button Insert adds the created color to the color palette at the position of the selected color in the palette. Button Replace replaces the selected color in the color palette with the modified color.

view - Contains commands that control the appearance of the current document window.

Page (Page)– Scales the Graphics Window to full page. Team Page increases or decreases the density of the view in the Drawing window so that the full page is displayed. The page format is adjusted using the command Page Layout from the menu file.

Fit to Window (Landing in the Window)- Scales the document to fit within the window. Team Fit to Window changes the magnification of all objects in the current Drawing window so that they fit within the borders of the window, providing the user with the ability to change the maximum zoom level that allows all objects to be seen in the active Drawing window.

actual size (true size)- Scales the document to its true size. Team actual size changes the magnification of the window to show the result at approximately true scale. For example, Full Screen- Restores the screen view to full screen view. Command After this command is selected, one inch on the screen equals one inch on the printed page when printed at 100% scale.

full screen allows you to view the map without the characteristics of the Drawing window. When this command is selected, the map and all associated objects are re-displayed, but the window characteristics are not displayed. In this case, it is impossible to mount the map, however, such a representation provides the user with objective information about the type of map being created. To return to the original view, click on any keyboard button or mouse button.

Zoom Rectangle (Change the scale of the image of the Rectangle)- Expands the selected area, thereby filling the entire window. Team Zoom Rectangle enlarges part of the Drawing window. This command is useful for performing detailed work on a specific area of ​​the Drawing window, as it expands the areas and allows you to work on them at a resized view.

Zoom In (Expand)- The map is displayed at twice the current scale. Team zoom in doubles the magnification within the window. The command also centers the window on the point of interest. To enlarge part of the Drawing window, you must click the tool zoom in on the Toolbar, or select the command zoom in from the menu view, and a pointer indicating the magnification method (plus) appears. Place the pointer on the area or object that should be centered during zooming. When you click the mouse button, the view will enlarge by a factor of two, and the point of interest will be displayed in the center of the window.

Zoom Out- The map is displayed at half the current scale. Team zoom out allows you to reduce the window image by half, and like the command zoom in, also centers the window on the point of interest.

Zoom Selected (Zoom selected image)- Fills the window with the selected object. Team Zoom Selected changes the magnification so that the selected objects get maximum size, possible in the figure window, when they are fully displayed.

Redraw- Redraws the document. Team Redraw clears the active window and redraws all objects from back to front. This command is used to remove unwanted residue or "dirt" that sometimes occurs during operation. It also allows you to see and locate objects hidden behind other objects as they are exposed. You can reorder objects using commands Move to Back and Move to Front.

Auto Redraw- Automatically redraws the map every time a change is made. Team Auto Redraw used to automatically redraw the map every time a change is made. When Auto Redraw disabled, you can use the F5 key or the command Redraw to redraw the map.

Draw - Creates text blocks, polygons, polylines, symbols, and shapes.

Text- Creates a text block. Team Text places the text of new entries anywhere in the Picture window. You can modify an existing text block by double-clicking on it. This allows you to edit the text, or change the font, point size, style, color, and linearization for the selected text. Text can be moved and resized using the mouse and can be rotated using commands Rotate, or Free Rotate on the menu Arrange (Accommodation).

To change the attributes of several text blocks at the same time, you must select all the text blocks that will be changed, and then select the command Text Attributes. Changes made to the window Text Attributes, will be applied to all selected text blocks.

Text blocks may include special non-printing codes (called Math Text Instructions, which change the text attributes of a line, such as font type, size, color, and style (bold, italic, strikethrough, and underline), within a single text block. Math text commands are useful for placing math equations on a map, or creating custom axis titles using mixed Greek and Roman characters.

Polygon (Polygon)- Creates a closed polygon. Team Polygon used to create a closed multilateral form. Polygons can display any fill pattern and line style. Polygon attributes can be changed by double-clicking on a completed polygon. Holding down the CTRL key limits vertex placement, so the line segments generated are limited to 45 degree angle increments. Clicking the right mouse button deletes the last vertex of the polygon. Pressing ESC allows you to exit the method without having to complete the current polygon. If the cursor touches the window border when creating a polygon, Surfer automatically moves the image.

Polyline (Polyline)- Creates a broken line. Team Polyline used to draw a line at any position on the page. Lines drawn in this way can have as many segments as needed. Polylines can display any line type or color and can include pointer arrows at either end of the polyline. The attributes of a polyline can be changed by double-clicking on a completed polyline.

Symbol (Symbol)- Creates a centered symbol. Team symbol is used to set a character at a specific position on a page. When choosing a team symbol, or the Symbol icon in the Toolbar, you can press the mouse button at the position where you want the symbol to appear. Symbol attributes can be changed later by double-clicking on the symbol.

The default symbol can be changed using the command symbol when nothing is selected. Each symbol created, after the default value is changed, uses the new symbol.

When multiple characters need to be specified, double-click the Symbol icon. Once the symbol tool is selected, the user remains in the symbol mode, allowing the user to create as many symbols as needed without having to return to the menu or Toolbar each time.

Rectangle- Creates a rectangle. Team Rectangle is used to create a filled rectangle or square at a specified position on the page. The padding and linetype can be changed by double-clicking on the completed rectangle.

Getting a rectangle. To draw a rectangle, you must click the mouse button in any corner of the future rectangle, and move the mouse to increase the size of the rectangle. Holding down the SHIFT key while getting a rectangle causes the starting point to become the center of the rectangle.

Getting a Square. To draw a square, you need to hold down the CTRL key while getting a rectangle, and the square will be displayed with a starting point, just like when drawing a rectangle.

Rounded Rect (Rounded rectangle)- Creates a rounded rectangle. The Rounded Rect command is used to create a filled rounded rectangle at a specified position on the page. Getting a Rounded Rectangle and Getting a Rounded Square identical to similar methods for obtaining a simple rectangle (square).

Ellipse (Ellipse)- Creates an ellipse. The Ellipse command is used to create a filled ellipse or a filled circle at a specified position on the page. Getting Ellipse and Gaining a Circle identical to similar methods for obtaining a rectangle (square).

Line Attributes (Line attributes)- Change the default line attributes or line attributes of selected objects. Allows you to change the type, color and thickness of the lines of selected objects, or set the value of attributes for the created objects.

Fill Attributes(Fill Attributes) – Changes the default value of fill attributes, fill attributes, or fill attributes of selected objects.

Text Attributes (Text Attributes)– Changes the default text attributes or attributes of the selected text.

Symbol Attributes (Symbol Attributes)- Changes the default symbol attributes or the selected symbol attributes.

Arrange - Contains commands that control the ordering and orientation of objects.

Move to Front(Move Forward)- Selected objects protrude in front of other objects.

Move to Back(Move Back)- Selected objects protrude behind other objects.

Combine(Connect)– Connects the selected objects together.

Break Apart(Divide)– Breaks the selected objects into separate components.

Rotate(Rotation)- Rotates the selected object around the specified angle.

Free Rotate(Free Rotation)- Rotates the object using the mouse.

Align Objects (Align Objects)- Objects are aligned within the bounding box.

Gri d (Grid) - Contains commands for creating and modifying a grid file.

Data (Data)- Builds a regular grid of points with a given step in X and Y in a rectangle bounded by coordinate lines (file with extension [.GRD]) from a set of X, Y, Z data. A grid file is required to build a structural map or surface plot, or to perform any action that requires a grid file, such as a mathematical grid, calculation of volumes and areas, smoothing, or mathematical calculation of grid residuals. Raw data of X and Y coordinates, collected in irregular form over the area of ​​the map area, Surfer interpolates to a regular rectangular grid in a [.GRD] format file.

Mesh building parameters can be controlled. Data Columns allows you to define columns for the X, Y, and Z values ​​in the data file. Grid Line Geometry allows you to define the limits and density of the grid. Edit windows X and Y direction allow you to define different grid limits, and determine the density of grid lines in both directions. Gridding Methods allows you to define the method used when interpolating the grid values ​​and adjust certain parameters of this method.

Function (Function)- Builds a grid file [.GRD], according to a user-defined function. Team function allows you to create a mesh file from a user-defined equation of two variables of the form Z=f(X, Y), using any of the mathematical functions available to the program Surfer.

Math (Mathematics)- Builds a mesh file [.GRD] by performing mathematical operations on an existing mesh. Math mathematically blends the grid point values ​​of two grid files that use the same coordinate values. This command creates an output grid file based on a specific mathematical function like C=f(A, B), where C is the output mesh file, A and B represent the original mesh files. A certain function is executed on the corresponding grid nodes with the same X and Y values. Function Math can also be performed on a single mesh or USGS DEM file. In this case, the same mathematical expression is applied to all nodes of the original grid.

Calculus (calculus)- Provides a choice of applied data interpolation for gridding. Team Grid Calculus Helps to identify quantities in a mesh file that are not visible when viewing a map's outline or 3D view.

Matrix Smooth- Smoothes the mesh using a matrix smoothing algorithm. Matrix Smooth calculates new values ​​of grid nodes by averaging or weighted backsampling. This cuts out unwanted "noise" or fine-scale information that is present in the original mesh file. The smoothed mesh file has the same limits and contains the same number of mesh nodes as the original file.

Spline Smooth (Spline - Smoothing)- Smoothes the mesh using the spline smoothing algorithm. Cubic spline interpolation is used to calculate nodes. Cubic spline interpolation uses a spline drawing technique to draw a smooth curve between characters. Line segments between adjacent signs - symbols can be represented by a cubic equation.

There are two ways of smoothing with splines: expanding the mesh or recalculating it. When expanding a mesh, nodes are inserted between existing nodes in the original mesh. If the mesh is recalculated, all nodes in the aligned mesh are recalculated.

Blank (Whitening)- Creates a clean mesh section in the [.GRD] file on an existing mesh [.GRD] file along the boundary specified in the [.BLN] file. To use the command Blank requires mesh files [.GRD] or USGS DEM slab file [.BLN], which must be created before executing the slab operation. The mesh file is created using the command Data, and an overlay file can be created in and saved in the project window.

The boundary can be assigned to an area inside or outside the overlap boundary. The closed mesh contains the same number of elements, the same coordinates, and the same limits as the original mesh file. The elements in the output grid are identical to the values ​​in the input grid, except for those where the overlap value is placed.

Convert- Team Convert allows you to convert a binary grid file [.GRD] to an ASCII grid file or vice versa, or convert a USGS DEM file to ASCII or a binary grid file. You can also convert a mesh file or USGS DEM file into an X, Y, Z data file. When you create a data file, all grid nodes are listed in separate columns, with the X coordinate in column A, the Y coordinate in column B, and the Z values ​​in column C. Format GSBinary (*.GRD) smaller than an ASCII grid file and takes up less disk space. Format GS ASCII (*.GRD) allows you to modify the file using a questionnaire Surfer or any ASCII editor that allows you to process big file. Format ASCII XYZ (*.DAT) allows to get X, Y, Z data file from grid file [.GRD].

Extract- Creates a mesh file that is a subset of an existing mesh file. The subsets can be based on some rows and rows from the input grid file. In this case, you can use a step factor that skips a specified number of rows and rows when reading information from the original grid. In this way, the mesh density can be reduced.

Transform (Transformation)- Changes the position of the XY coordinates of a grid node within the grid file. Team Transform does not change the Z values ​​contained in the mesh file, only the position of the Z values ​​within the mesh file. Teams Transform use the translation, scaling, rotation, or mirroring of grid node values ​​within the grid file. Option offset allows you to add or subtract the specified X or Y offset. Option Scale allows you to change the scale. Option Rotate allows you to rotate the grid by a factor of 90. Options Mirror X and Mirror Y create a mirror image of the extremum X and Y, respectively.

Volume (Volume)- Performs calculation of volume and area between grid nodes of [.GRD] file. Team Volume can calculate the volume of the entire surface and the volume of the cutout, as well as the difference between the two meshes. The command also calculates the surface area. The greater the grid density, the more accurately the calculations will be made.

Slice– Produces a profile string from a grid [.GRD] file and a file boundary. A terrain profile data file is created based on the surface file [.GRD] and the floor file [.BLN].

Residuals- Computes the difference between grids [.GRD] surface values ​​and original data values. Team Residuals calculates the vertical difference between signs - symbols and the plotted coordinate grid of the surface. The remainder is the difference between the Z value of a point in the data file and the interpolated Z value at the same point (X, Y) placed on the plotted surface. Team Residuals can give a quantitative measure of the difference between the mesh file and the original data, or can be used to determine the Z values ​​at any grid point (X, Y).

Calculations are made according to the formula: Zres = Zdat – Zgrd where Zres - residual difference; Zdat - Z value in the data file; Zgrd is the Z value in the mesh file.

In order to obtain statistical information regarding the calculated residual impurities, it is necessary to use the command Statistics on the menu Worksheet Compute.

Grid Node Editor– Allows you to change the individual grid nodes in the grid [.GRD] file. In the window Grid Node Editor, the position of the grid nodes is indicated by the "+" sign. The active vertex is highlighted, for which you can enter a new Z value.

Map (Map) - Contains commands for creating and modifying maps.

Load BaseMap (Load Base Map)- Creates a base map from an edge file, metafile, or bitmap file. Team Load BaseMap imports the boundary map to use as the main map. Main maps can be independent of other maps in the window Plot, or can be mixed with other cards (using the command Overlay Maps).

Contour (Horizontal)- Generates a structural map from a mesh file or DEM file ( Figure 3.1). Structural Map - A graph based on the X, Y, Z values ​​in a grid file or DEM file. The horizontal is determined by the Z values, or, in other words, the step of the relief section. The mesh file contains a series of Z values ​​fixed on a regularly divided (X, Y) placement matrix. When a structural map is created, the mesh file is interpreted. Contours are output as straight line segments between grid lines in the grid file. The point where the horizontal intersects the grid line is based on an interpolation between the Z values ​​at adjacent grid points. When creating a height map, you can control the type, thickness, and color of lines, as well as the fill color between contour lines.

Post (Post)- Creates a map showing the location of the data points. Post maps can cover structural maps, allowing you to put the necessary symbols of the original on the map, or other information about the location of the point. Labels used on the map can be assigned text attributes (Text Attributes).

Classed Post (Classified Post)- Creates a map showing data point locations based on other data areas. Team classed post allows you to plot points using different symbols for different ranges of recorded data ( Rice. 3.2).

Image- Creates a bitmap image map from a mesh file or DEM file. Raster maps use different colors to represent elevation in terrain. The colors on the maps are related to elevation values. A color with a brightness of 0% is passed to the minimum Z value in the mesh file, and a color with a brightness of 100% is passed to the maximum Z value. Surfer automatically blends colors between grid values ​​so that the result is a smooth color gradation across the map. Each point can be assigned a unique color, in which case the colors are automatically blended between adjacent points. Image to arts can scale, change borders, or move in the same way as other types of maps, however, they cannot rotate or tilt and cannot be blended with a surface map ( Fig 3.3).

Shaded Relief- Generates a shaded bump map from a mesh file or DEM file. Shaded Bump Maps - raster maps based on a mesh file or DEM file. These maps use different colors to indicate the slope of the terrain and the slant direction relative to the user-defined direction of the light source. Surfer defines the orientation of each grid cell on the surface, and assigns a unique color to each grid cell. Since colors are assigned to grid cells, it makes no sense to use this command on grids with large steps.

The colors in shaded bump maps are related to percentage values ​​of incident light. You can think of a light source as the sun shining on a topographical surface. The maximum color (at 100%) is assigned where the rays are perpendicular to the surface.

Surface (Surface)- Creates a surface plot from a grid file or DEM file. A surface plot is a 3D representation of a file

grid that can be displayed with any combination of X, Y, or Z rows.

When constructing a surface, you can set its display parameters (X, Y or Z lines, fill colors, etc.).

Show (Insert)- Controls the display of options on the selected map or overlay. Team show toggles the display of options on the selected map on or off. The highlighted parameters in the command list are displayed on the map.

Edit- Controls the axis options for the selected axis. Team Axis Edit allows you to adjust all parameters for the selected axis. Sets the maximum and minimum value of the axis, as well as the interval between values.

scale- Controls the scaling of the selected axis. Team Axis Scale defines the limits of the axis, the distance between labels along the axis, the position of the selected axis relative to other parameters on the map or surface plot.

Grid Lines- Controls the display of grid lines on the map.

Scale Bar (Linear scale)- Creates a linear scale. The ruler is divided into four equal parts and can be scaled to any user-defined parameters. By default, the scale is scaled about the x-axis.

background- Controls the background of the map, aligns and replenishes the attributes. The map background limits match the axis limits on the contour, and the base on the surface plot.

Digitize- Reads the coordinates from the map and writes them to the data file. When using this command, moving the cursor across the selected map, the X and Y coordinates for the current mouse position are shown in the status bar. When pressing the left key, the coordinates of the current point are written to the data file.

3D View- Controls the rotation and skew of the selected map or overlay ( Rice. 3.5). Team 3D view sets

orientation of the map in the drawing window. Maps can be rotated about the Z-axis, its tilt and perspective view can be controlled. The 3D rotation command can be applied to all selected maps at the same time.

This option allows you to view the image in two projections: perspective, which creates a visual result, as a result of which the size of the surface changes with distance from the browser, and orthographic projection of the surface onto a plane, when parallel lines remain parallel. This projection is the default for surface plots or other cartographic representations.

scale- Controls the scale for the selected map or overlay. Team Scale defines how to scale the map blocks relative to the page blocks in the window Plot. By default, scaling is done so that the longest side of the map, either the X or Y axis, is 6 inches. When plotting surface plots, the same X and Y rules apply, and the Z axis is scaled to be 1.5 inches long, regardless of the number of blocks in the Z axis.

Limits- Determines the extent of the selected map or overlay. You need to use the command Limits to define the limits of the X and Y values. This command is useful for partially displaying the rendered map, but cannot be applied to surface maps.

Stack Maps– Superimposes and aligns the selected cards on the page. Using this command is useful when you want to stack two or more surfaces, or a structure map over a surface. To use this command, the selected cards must have the same X and Y limits, use the same 3D representation, and be displayed approximately vertically on the page where they are to perform.

Overlay Maps- Merges the selected maps into one layer. Team Overlay Maps mixes two or more maps into a single map, enabled by a single set of X, Y, and Z parameters. Overlays can contain any number of basemap, contour maps, post or classed post maps, but can contain only one surface plot.

Edit Overlays- Provides you with control over overlay components. Team Edit Overlays allows you to easily select any of the objects in the window. Any card can be removed from the overlay, except for the surface drawing.

These are the main functionalities of the program Surfer, which we used in the implementation of the experimental part of the graduation project.

Mikhail Vladimirovich Morozov:
personal site

Mathematical models (lesson, map-2): Principles of working with Golden Software Surfer

Well " Mathematical modeling methods in geology"

Golden Software Surfer is the world's leading software for building spatial models of numerical variables such as geophysical or geochemical field values, etc. This chapter will help you get started with the program, avoiding common mistakes newbie.

PRACTICE

Introduction to Surfer by Golden Software

The purpose of the software in a nutshell: to build a map of a numerical parameter on the required scale (in any external execution - with points, isolines, color gradations, as a 3D surface, as a vector field) and arrange it for presentation.

What the program DOES NOT do: Surfer is a program for building digital surface models in given parameter. It is not suitable for "coloring" the territory, i.e. to create a map showing the relative position of point, line and area objects, as a drawing (i.e. geographical, political and other similar maps). To create such maps, other software is required (ArcInfo, MapInfo, and many others).

WHAT SURFER IS LIKE. The program toolkit consists of two parts: (1) mathematical part- for creating and analyzing a surface map - a unique powerful program that has analogues (for example, Oasis); (2) decoration part similar to any program for creating vector graphics, which allows you to create lines and other objects, and then individually modify them (leaders in this area are Corel Draw, Adobe Illustrator ), in terms of drawing Surfer, of course, is inferior to special graphics packages, because. it is created as carto graphics software, not just graphics software

Let's launch the Surfer program and get acquainted with the logic of working in it.

The Surfer project file (*.SRF extension) consists of a set of objects placed on a printed sheet(by default A4 format, its outlines are indicated in the Surfer window). Objects can be selected with the mouse and perform operations with them similar to the usual actions in a vector graphics program (scaling, moving, changing properties). Individual objects can be part of groups. Any map must be included in a group of type Map, which is assigned a coordinate network common to all objects of this group.

Please note: if you just draw graphic object(line, rectangle, etc.) it will be placed on the printed sheet, but will not have binding to coordinates maps, even if it is drawn on top of it, because will not be tied to geographic coordinates. If you want to have a line or polygon anchored to coordinates, you need to create a path object ("stroke") using the command base map, and then add it to the Map group of the corresponding map.

AT upper left corner window surfer located Object Manager , which allows you to observe the order of displaying objects on the screen and when printing (in the manager, from top to bottom, objects follow as layers, respectively, blocking each other when displayed on the screen or printed sheet).

In order to CORRECTLY WORK WITH THE PROJECT, you must remember to do the following:

a) each object (which by default receives an abstract name like "Line" or "Map") IMMEDIATELY AFTER CREATION, give a clear name by clicking on the name with the mouse, for example, "Contour of works 2013" - for outlining the territory, "lgCu" - for the map by logarithms of grades, etc. Otherwise, I assure you, the number of objects imperceptibly for you will become so huge, and the names of objects of the same type will be the same, that you will completely get confused in the project.

b) Arrange Layers in the correct order - those objects that should be displayed or printed on top of others must be drag with mouse up in the object manager list.

in) Each new card, even if it is built on a common database, is added to the project as independent object, even if it falls into the same place on the sheet when created. Mouse these cards can be moved and placed side by side. Sometimes this is necessary - for example, to print maps side by side in isolines, say, for copper and zinc. But if you want to combine maps - for example, put points of fact maps on top of the map in isolines, these maps need to be reduced into one, by dragging any of them into a group Map where the second card is located. At the same time, the group Map the first card (if it did not include anything else) will disappear, and the new group Map will contain two maps as two adjacent layers. You can drag an object with the mouse when next to it is displayed horizontal arrow pointer. At this moment, you can release the mouse and the object will "land" in the place where the arrow was pointing. If you drag the object where it is not allowed, then the pointer will take the form of a prohibition road sign.

d) If unnecessary objects interfere with viewing (or you do not want to print them), uncheck the box to the left of the object's name, and it will disappear. So it is convenient to change to view the map in contour lines according to different parameters, because only one can be displayed at a time.

AT bottom left corner window surfer located Object property manager if some object is in this moment active, i.e. selected with the mouse. The property manager combines on tabs and groups all object parameters that can be changed, ranging from georeferencing to coordinates and ending with color, line texture, etc. In addition to the Manager, some of the properties can be edited using control panels Position/Size(location on the sheet relative to the upper left corner of the printed sheet, the height and width of the object).

Mapping tools for creating, modifying and analyzing surfaces are collected in the menu Grid. Its commands contain the whole range of tools from the spreadsheet editor to mathematical modules for creating and processing grid files ("grids" - *.GRD files). These features and their most important features are discussed in the chapter "Building a grid file" and "Choice of a mathematical model, kriging and semivariogram".

The main component of Surfer is set of cartographic tools, i.e. commands for displaying prepared surfaces ("grids"). The main ones are collected in the menu. Map - New and partially duplicated in the toolbar Map.

If necessary, Surfer allows you to run the built-in spreadsheet editor (menu Grid - Data). With this command you can open excel file or another spreadsheet and resave the data in Surfer's native *.DAT format, which is actually a text file with column separators. Of course, the built-in editor is nothing compared to the capabilities of "proprietary" software for managing spreadsheets, such as Microsoft Excel , Open Office Calc etc., so I do not recommend using it. It makes sense to work with DAT files only as a last resort, or if the source data tables are already prepared in advance in the DAT format. In a normal situation, the user works with data created in an *.XLS spreadsheet format, which is directly processed by all Surfer modules for building surfaces and maps.

Let us mention important toolbar.

Toolbar view(View) contains zoom buttons, with which it is convenient to change the size of the viewport in one click, as well as scale and move objects.

Toolbar Map(Map) contains all the main buttons for creating maps, which speed up the work, because. eliminates the need to select from the menu Map - New.

For drawing, there are graphic tools collected on the panel Drawing(Draw): Buttons for entering text, polygon, polyline, symbol, standard shapes (rectangle, rectangle with rounded corners, ellipse), a smooth curve (i.e. a Bezier curve based on anchor points), and an anchor point editing tool (similar to the same tool in Corel Draw and similar vector graphics software). General form all panels are given in the figure at the end of the page.

Don't forget to also set unit of measure: select centimeters instead of inches by default (menu Tools - Options, further section Environment - Drawing, field Page Units).

And finally, the most important thing: the shape of the final map. It's no secret that not everyone has the Surfer program in their hands, therefore, the final form of the map must correspond to the generally accepted format. In our case the best option will export the map to a bitmap file JPEG format. Before exporting, you need to check the external view of the project, make sure that the layers are correctly arranged, disable unnecessary layers in the object manager, and do not forget to write all the necessary titles and comments. After that, we select all the objects, group them (this is not necessary, but it is by no means harmful for protection against accidental shifts of objects relative to each other). Export is done through the menu File-Export, on click ctrl+e or using the dedicated button on the toolbar. By default, Surfer offers export to *.BLN format, change it to *.JPG. In the next window, we can edit the resolution of the final image (300 dpi by default, 200 dpi is often good, which saves file size). The Export Options window has a tab jpeg options, where you can select the desired compression level (do not get carried away and do not squeeze the picture, be sure to check the quality of the result using the example of the smallest inscriptions and icons). That's all!