History of digital cartography. Electronic cartography and electronic cartographic systems. "Digital cartography" in books

8.1. The essence and objectives of the course “Digital Cartography”

The course “Digital Cartography” is an integral part of cartography. He studies and develops
teaches the theory and methods of creating digital and electronic maps, as well as map automation
tographic works.

Cartography has now moved to a new qualitative level. Due
With the development of computerization, many map creation processes have completely changed. Singing
New methods, technologies and directions of mapping developed. You can select times
personal areas that cartography deals with today: digital mapping
tion, three-dimensional modeling, computer publishing systems, etc. In this regard
new cartographic works have appeared: digital, (electronic and virtual)
maps, animations, 3D cartographic models, digital terrain models. Cro
In addition to creating computer maps, the task is to create and maintain digital cartography databases
physical information.

Digital maps are inseparable from traditional maps. Theoretical foundations of cartography
The knowledge accumulated over centuries remains the same, only the technical means have changed
creating maps. The use of computer technology has led to significant changes
technologies for creating cartographic works. The technology has become much simpler
completion of graphic work: labor-intensive drawing, engraving and other manual tasks have disappeared
new works. As a result, all traditional drawing materials fell out of use
and accessories. A cartographer who knows the software can quickly and efficiently
Perform complex cartographic work efficiently. There are also many opportunities
carry out design work at a very high level: design of thematic maps,
atlas covers, title pages, etc.

With the introduction of computer technology, the processes of compiling and preparing
preparation of maps for publication. Eliminates the need to make high-quality manual copies
compiler's original (publisher's original). Design original, executed
on a computer, makes it very easy to edit and correct proofs
tagging without deteriorating its quality.

The advantages of computer technology are not only ideal quality
graphic work, but also high accuracy, a significant increase in productivity
labor, improving the printing quality of cartographic products.

8.2. Definitions of digital and electronic
cartographic works

The first work on creating digital maps began in our country at the end of
70s Currently, digital maps and plans are mainly created using traditional methods.
ny originals of maps and plans, compiler’s originals, circulation prints and other
cartographic materials.

Digital cards - digital models of objects, presented in encoded form
numeric plan coordinates x and y and applicate I.

Digital maps are logical-mathematical descriptions (representations)
mapped objects and relationships between them (relationships of terrain objects in the visual
de their combinations, intersections, proximity, different heights in relief, orientation along the sides
light to us, etc.), formed in coordinates, projections accepted for conventional maps,
systems of conventional signs, taking into account the rules of generalization and requirements for accuracy. Like
For ordinary maps, they differ in scale, subject matter, spatial coverage, etc.

The main purpose of digital maps is to serve as the basis for the formation of databases and
tomatic compilation, analysis, transformation of maps.

In terms of content, projection, coordinate and height systems, accuracy and layout, digital
maps and plans must fully meet the requirements for traditional
maps and plans. All digital maps must comply with topological
communication between objects. There are several definitions of digital
and electronic cards. Some of them are given in this topic.

Digital card - presentation of map objects in a form that allows
computer to store, manipulate, and display the value of their attributes.

Digital card - it is a database or file that becomes a map when
GIS creates a hard copy or image on the screen (V. Huxhold).

Electronic cards - these are digital maps visualized in a computer environment
where using software and hardware, in accepted projections, systems
conventional signs, subject to established accuracy and design rules.

Electronic atlases- computer analogues of conventional atlases.

Capital atlases are created using traditional methods for a very long time, decades.
Therefore, very often, even in the process of creation, their content becomes outdated. Electronic atlas
sys can significantly reduce the time of their production. Maintaining electronic cards
and atlases at the modern level, their updating is currently being done very quickly
ro and quality.

There are several types of electronic atlases:

Atlases are for visual viewing only (“flipping through”) - viewer atlases.

- Interactive atlases, in which you can change the design, ways of depicting
analysis and classification of mapped phenomena, receive paper copies of maps.

- Analytical atlases (GIS atlases) , allowing you to combine and match
maps, carry out their quantitative analysis and evaluation, overlay maps on each other
friend.

In many countries, including Russia, National atlases have been created and are being created.
The National Atlas of Russia is an official state publication created
on behalf of the Government of the Russian Federation. The National Atlas of Russia gives com
a comprehensive view of nature, population, economy, ecology, history and culture
countries (Figure 8.1). The atlas consists of four volumes: volume 1 - “General characteristics of the territory
riy"; volume 2 - “Nature. Ecology"; volume 3 - “Population. Economy"; volume 4 - “History.
Culture".

Rice. 8.1. National Atlas of Russia

The atlas is produced in printed and electronic forms (the first three volumes, electronic
the throne version of the fourth volume will be released in 2010).

Cartographic animations- dynamic sequences of electronic
cards that convey on the computer screen the dynamics and movement of the depicted
objects and phenomena in time and space (for example, the movement of precipitation,
moving vehicles, etc.).

We often see animations in everyday life, for example,
television weather forecast maps, on which the movements of fronts are clearly visible,
areas of high and low pressure, precipitation.

To create animations, all kinds of sources are used: remote control data
sounding, economic and statistical data, direct field data
observations (for example, various descriptions, geological profiles, meteorological observations
tions, census materials, etc.). Dynamic (moving) cartographic images
Russian objects can be different:

Moving the entire map across the screen and individual content elements across the map;

Changing the appearance of symbols (size, color, shape, brightness, internal
early structure). For example, populated areas can be shown as pulsating
special punches, etc.;

Cartoon sequences of frame cards or 3D images.
This way you can show the dynamics of glacier melting, the dynamics of the development of erosion processes;

Panning, rotating computer images;

Scaling an image, using a dissolve or fade effect
object;

Creating the effect of movement over the map (flying around, driving around the territory).

Animations can be flat and three-dimensional, stereoscopic and, in addition, can
can be combined with a photographic image.

Three-dimensional animations combined with a photographic image are called virtual
new cards(the illusion of a real area is created).

Technologies for creating virtual images can be different. Usually,
First, a digital map is created based on a topographic map, aerial or satellite image.
del, then - a three-dimensional image of the area. It is painted in the colors of the hypsometric
scales and then used as a real model.

8.3. Concept of geographic information systems (GIS)

The first geographic information systems were created in Canada, the USA and Shv tions for
studying natural resources. The first GIS appeared in the early 60s. In Canada. Home
The goal of the Canadian GIS was to analyze land inventory data from Ka
nady. In our country, such research began twenty years later. Currently
Nowadays, in many countries there are various geographic information systems that
solve a variety of problems in various industries: economics, politics, ecology,
Dastre, science, etc.

There are dozens of definitions of GIS in the domestic scientific literature.

Geographic Information Systems (GIS)- hardware-software com
complexes that provide collection, processing, display and distribution of spaces
vein-coordinated data (A.M. Berlyant). One of the functions of GIS is the creation and use
use of computer (electronic) maps, atlases and other cartographic products
information.

Geographic information system- is an information system designed for
collection, storage, processing, display and distribution of data, as well as receiving
based on them, new information and knowledge about spatially coordinated objects
and phenomena.

The essence of any GIS is that it is used to collect, analyze,
thematization, storage of various information, creation of a database. The most convenient form
presentation of information to users - cartographic images, in addition,
information can also be presented in the form of tables, diagrams, graphs, and texts.

A distinctive feature of GIS is that all information in them is presented
in the form of electronic maps that contain information about objects, as well as spaces
natural connection of objects and phenomena. Electronic maps differ from paper maps
the fact that each conventional sign (object) depicted on the electronic map has a corresponding
there is information entered into the database. This allows you to analyze them in mutual
connections with other objects. By pointing the mouse cursor, for example, at a certain area, you can
obtain all the information entered about him into the database (Fig. 8.2).

Rice. 8.2. Getting information about an object from the database

In addition, geographic information systems work with map projections,
which allows for projection transformations of digital and electronic maps
(Fig. 8.3).

Rice. 8.3. Selecting a map projection in GIS Mar!p&Pgo&88yupa1

Currently, specialized land geographic information systems have been created
topics, cadastral, environmental and many other GIS.

Using the example of the administrative map of the Tomsk region, we will consider the capabilities of GIS.
We have a database that contains information about the area sizes of Tom districts
region and the number of residents in each district (Fig. 8.4). Based on this data we
we can obtain information about the population density of the Tomsk region, in addition, about
gram constructs a map of population density (Fig. 8.5).

Rice. 8.4. Creating a thematic map based on data entered into the database

Rice. 8.5. Population density map of the Tomsk region, built automatically

Thus, the distinctive features of GIS are:

Geographical (spatial) referencing of data;

Storing, manipulating and managing information in a database;

Opportunities for working with projections of geographic information;

Obtaining new information based on existing data;

Reflection of spatio-temporal connections between objects;

Ability to quickly update databases;

Digital relief modeling;

Visualization and output of data.

Digital maps can be directly perceived by humans when visualizing electronic maps (on video screens) and computer maps (on a solid basis), and can be used as a source of information in machine calculations without visualization in the form of an image.

Digital maps serve as the basis for the production of conventional paper and computer maps on a solid substrate.

Creation

Digital maps are created in the following ways or a combination thereof (actually ways of collecting spatial information):

· digitization (digitization) of traditional analog cartographic works (for example, paper maps);

· photogrammetric processing of remote sensing data;

· field survey (for example, geodetic tacheometric survey or survey using instruments of global satellite positioning systems);

· desk processing of field survey data and other methods.

Methods of storage and transmission

Since models that describe space (digital maps) are very non-trivial (unlike, for example, raster images), specialized databases (DBs, see spatial database) are often used to store them, rather than single files of a given format.

To exchange digital maps between various information systems, special exchange formats are used. These can be either popular formats of any software manufacturers (for example, DXF, MIF, SHP, etc.), which have become a de facto standard, or international standards (for example, the Open Geospatial Consortium (OGC) standard , like GML).

Cartography

Cartography (from the Greek χάρτης - papyrus paper, and γράφειν - to draw) is the science of research, modeling and displaying the spatial arrangement, combination and interrelation of objects, natural phenomena and society. In a broader interpretation, cartography includes technology and production activities.

The objects of cartography are the Earth, celestial bodies, starry sky and the Universe. The most popular fruits of cartography are figurative and symbolic models of space in the form of: flat maps, relief and volumetric maps, globes. They can be presented on solid, flat or voluminous materials (paper, plastic) or as an image on a video monitor.

Sections of cartography

Mathematical cartography

Mathematical cartography studies ways to display the Earth's surface on a plane. Since the surface of the Earth (approximately spherical, to describe which the concept of the earth’s spheroid is often used) has a certain curvature that is not equal to infinity, it cannot be displayed on a plane while preserving all spatial relationships at the same time: angles between directions, distances and areas. Only some of these relationships can be preserved. An important concept in mathematical cartography is a map projection, a function that specifies the transformation of the spheroidal coordinates of a point (that is, coordinates on the earth’s spheroid, expressed in angular measure) into flat rectangular coordinates in one or another map projection (in other words, into a map sheet that can be spread out in front of you on the table surface). Another significant section of mathematical cartography is cartometry, which allows using map data to measure distances, angles and areas on the real surface of the Earth.

Mapping and design

Mapping and design is a field of cartography, a field of technical design that studies the most adequate ways to display cartographic information. This area of ​​cartography is closely interconnected with the psychology of perception, semiotics and similar humanitarian aspects.

Since maps display information related to a wide variety of sciences, such sections of cartography as historical cartography, geological cartography, economic cartography, soil cartography and others are also distinguished. These sections relate to cartography only as a method; in content they relate to the corresponding sciences.

Digital cartography

Digital (computer) cartography is not so much an independent section of cartography as its tool, due to the current level of technology development. For example, without canceling the methods of recalculating coordinates when displaying the Earth’s surface on a plane (studied in such a fundamental section as mathematical cartography), digital cartography has changed the methods of visualizing cartographic works (studied in the section “Drawing up and design of maps”).

So, if earlier the author’s original map was drawn in ink, today it is drawn on a computer monitor screen. To do this, they use Automated Mapping Systems (ACS), created on the basis of a special class of software. For example, GeoMedia, Intergraph MGE, ESRI ArcGIS, EasyTrace, Panorama, Mapinfo, etc.

At the same time, one should not confuse ACN and Geographic Information Systems (GIS), since their tasks are different. However, in practice, the same set of software is an integrated package used to build both ACC and GIS (prominent examples are ArcGIS, GeoMedia and MGE).

Creation of electronic maps (contours) of fields.

For effective management of an agricultural enterprise, it will not be superfluous to know exactly what acreage you have. It is not uncommon for farm managers and agronomists to only approximately know the size of their fields, which negatively affects the accuracy of calculating the required fertilizers and calculating the yield. Using a GPS receiver, a field computer and special software, you can obtain electronic maps (contours) of fields with centimeter accuracy!

Resource-saving technologies, including precision agriculture, involve working with electronic field maps. This is the geographic information base on the basis of which almost all agrotechnical operations in precision agriculture are carried out. For example, one of the most complex agrotechnical operations of precision farming - differentiated application of mineral fertilizers is based on maps of the distribution of nutrients (N, P, K, Humus, ph) across the field. For this purpose, an agrochemical examination of farmland is also carried out.

But even if you do not use electronic field maps for the further use of precision farming technologies, the benefits of creating such maps are obvious. Knowing the exact areas of your fields and the distances between them, you can more efficiently and effectively:

1. Calculate the amount of necessary fertilizers and agrochemicals, as well as seed material

2. Take into account the resulting yield

3. Calculate the planned consumption of fuel and lubricants

4. Maintain annual records of sown areas with high accuracy for each crop

5. Maintain the history of fields (crop rotations)

6. If necessary, prepare visual reports of high accuracy (printing maps)

The creation of field contours is carried out using a GPS receiver, a field computer and software combined into a single hardware and software complex. In the "polygon" mode, you need to go around or bypass the field along its border and save the resulting contour. When saving, you can specify the field name and other necessary attributes and notes. After saving the contour, we will know the exact area of ​​the field.

The software also allows you to apply other geoinformation information: lines and points. Lines can be used when marking working areas in the fields. For example, if you already have electronic maps of your fields for last year and you only need to record the placement of crops in the fields this year, then there is no need to delineate the fields again. It is only necessary to draw demarcation lines between crops, and only if two or more crops are cultivated in one field.
Points are used to map field features such as pillars, large rocks, and others.

All received geoinformation from the hardware and software complex must be transferred to a desktop computer for further analysis and use in calculations and in making management decisions. Geographic information software (GIS) must also be installed on the desktop computer, which will allow you to work correctly with the information received in the fields. For these purposes, we recommend using the MapInfo © program.

In principle, you can use any GIS system that works with the .SHP (Shape) format. Almost all GIS systems can work correctly with this format. However, MapInfo © is, in our opinion, the optimal choice for recording acreage and maintaining field history. In MapInfo. You can create thematic maps, overlay the contours of your fields on satellite and aerial photographs, as well as on digitized topographic maps. MapInfo also has a handy tool for measuring distances (for example, measuring the distance from a garage to a field).

You can count from one thousand nine hundred and fifty-seven. This year, the Massachusetts Institute of Technology (USA) produced the first digital model of the map's relief and terrain, which was subsequently used to design highways. This indicates that in cartography, from the mid-twentieth century, new technological map-making and map-publishing processes and methods began to develop, which have been improved to the present day. The main directions and trends for improvement in them can be identified:

• technological (electronic) methods for creating maps;
• digital ways of organizing banks and databases;
• geoinformation mapping technologies;
• formation of maps in computer networks;
• development of virtual mapping.

For more effective use of scientific and technological processes in the development of cartography, the fastest delivery of the products created by it to the end user is required. Then they will be promptly used by consumers to solve specific problems they set. In modern realities, all scientific and production sectors, including digital cartography, are focused on meeting such requests and needs of society. Thus, with the help of digital technologies, cartography is transformed from educational and simple means of orientation into mathematical tools and methods of design, organization, management and planning. It is already obvious that technological progress has influenced the ways of using cards, of which we highlight the following:

• communication methods;
• spatial information;
• systemic decision making.

The essence of digital cartography

Digital cartography can be presented in three or even four meaningful forms:

• section of cartographic science;
• manufacturing industry;
• new technology.
• tool for visualizing images of cartographic products.

First of all, as a branch of cartographic science, digital cartography is engaged in the study and display of the spatial location of various objects of social activity, all kinds of natural phenomena, their digital modeling and relationships.

With the application and use of automated manufacturing processes, new computer technologies and a diverse visual range of images, digital cartography is particularly popular among both consumers and specialists. The production of cartographic products, as an industrial production, is a multifunctional technological process using modern technologies and is in demand as an electronic product.

It is worth remembering how maps were previously constructed. Entire full-time cartographic groups and thematic parties were created, the services of which arose in production. All received shooting information was recorded in ink on tracing paper or a denser base. The high labor intensity, significant time costs and scrupulousness in the entire mapping process made the process slow. Now all this is being replaced by computer technology, with the possibility of faster and more accurate execution of projects, ease of updating and editing maps.

Benefits of digital mapping

Comparing all the previous and current capabilities of various methods of constructing maps, including the economic component of market efficiency, we can highlight the following advantages of digital cartography:

• transmission of accurate information about the object, virtually eliminating the possibility of errors, due to the use of computer automation in calculations;
• speed of processing and obtaining the final result with higher labor productivity;
• a more economical way to create maps with less labor;
• the possibility and convenience of both editing and periodically updating maps on the same mathematical and geodetic basis.

It should also be noted that digital cartography is increasingly occupying space in the global information flow, penetrating into various areas of interesting modern life on the planet and winning over significant layers of users of its products, thereby creating increased demand. This situation occurs as it develops:

• new (computer) technologies of cartographic and geographic information systems;
• new (space) methods of geodetic spatial positioning and determining the location of all objects;
• improving the compilation of maps, increasing the accuracy and speed of mastering new popular cartographic products.

Types of digital cartographic production

Digital mapping production in its modern form is engaged in the following production processes to obtain certain results:

• development of digital standard maps and other cartographic materials necessary for this in the form of information arrays of the entire set of objects;
• creation of thematic maps using existing digital mathematical and cartographic foundations;
• maintaining digital databases of various information, including state borders;
• digital mapping based on satellite and aerial photographs;
• digital application of topographic map construction.

Digital mapping production processes

Digital cartography is a complex technological product that represents cartographic production, consisting of the following production processes:

• editorial preparatory period for compiling a digital map;
• incoming control of source materials;
• classification of objects of prepared documentation;
• object encodings;
• descriptions of digital map objects;
• editing maps;
• quality control;
• updates;
• conversion to exchange format;
• conversion to a given format;
• digitization of map materials;
• vectorization of maps;
• automation of cartographic generalization;
• digital map summary;
• control of card summary;
• transfer to the Topographic Maps Fund.

8.1. The essence and objectives of the course “Digital Cartography”

The course “Digital Cartography” is an integral part of cartography. He studies and develops the theory and methods of creating digital and electronic maps, as well as the automation of cartographic work.

Cartography has now moved to a new qualitative level. Due to the development of computerization, many map creation processes have completely changed. New methods, technologies and areas of mapping have emerged. It is possible to identify various areas that cartography deals with today: digital mapping, three-dimensional modeling, computer publishing systems, etc. In this regard, new cartographic works have appeared: digital, (electronic and virtual) maps, animations, three-dimensional cartographic models, digital models terrain. In addition to creating computer maps, there is the task of creating and maintaining databases of digital cartographic information.

Digital maps are inseparable from traditional maps. The theoretical foundations of cartography, accumulated over centuries, have remained the same, only the technical means of creating maps have changed. The use of computer technology has led to significant changes in the technology for creating cartographic works. The technology for performing graphic work has become much simpler: labor-intensive drawing, engraving and other manual work have disappeared. As a result, all traditional drawing materials and supplies fell out of use. A cartographer who knows the software can quickly and efficiently complete complex cartographic work. There are also many opportunities to carry out design work at a very high level: design of thematic maps, atlas covers, title pages, etc.

With the introduction of computer technology, the processes of compiling and preparing maps for publication were combined. There is no longer a need to make a high-quality manual copy of the compiler's original (publishing original). The design original, made on a computer, makes it very easy to edit and correct proofreading comments without compromising its quality.

The advantages of computer technology are not only the ideal quality of graphic work, but also high accuracy, a significant increase in labor productivity, and an increase in the printing quality of cartographic products.

8.2. Definitions of digital and electronic cartographic works

The first work on creating digital maps began in our country in the late 70s. Currently, digital maps and plans are mainly created from traditional original maps and plans, compiler’s originals, circulation prints and other cartographic materials.

Digital maps are digital models of objects, presented in the form of plan coordinates x and y encoded in numerical form and applicate z.

Digital maps are logical-mathematical descriptions (representations) of mapped objects and the relationships between them (relationships of terrain objects in the form of their combinations, intersections, proximity, differences in elevation in relief, orientation to the cardinal points, etc.), formed in the coordinates accepted for conventional maps , projections, systems of conventional signs, taking into account the rules of generalization and accuracy requirements. Like regular maps, they vary in scale, theme, spatial coverage, etc.

The main purpose of digital maps is to serve as the basis for the formation of databases and automatic compilation, analysis, and transformation of maps.

In terms of content, projection, coordinate and elevation systems, accuracy and layout, digital maps and plans must fully meet the requirements for traditional maps and plans. All digital maps must respect topological relationships between objects. There are several definitions of digital and electronic maps in the literature. Some of them are given in this topic.

A digital map is a representation of map features in a form that allows a computer to store, manipulate, and display the value of their attributes.

A digital map is a database or file that becomes a map when a GIS creates a hard copy or image on the screen (W. Huxhold).

Electronic cards– these are digital maps visualized in a computer environment using software and hardware, in accepted projections, systems of symbols, subject to established accuracy and design rules.

Electronic atlases– computer analogues of conventional atlases.

Capital atlases are created using traditional methods for a very long time, decades. Therefore, very often, even in the process of creation, their content becomes outdated. Electronic atlases can significantly reduce production time. Maintaining electronic maps and atlases at the modern level, updating them is currently being done very quickly and efficiently.

There are several types of electronic atlases:

Atlases for visual viewing only ("flipping") - viewer atlases.

Interactive atlases, in which you can change the design, methods of depiction and classification of mapped phenomena, and receive paper copies of maps.

Analytical atlases(GIS atlases), which allow you to combine and compare maps, carry out their quantitative analysis and evaluation, and overlay maps on each other.

In many countries, including Russia, National atlases have been created and are being created. The National Atlas of Russia is an official state publication created on behalf of the Government of the Russian Federation. The National Atlas of Russia gives a comprehensive picture of the nature, population, economy, ecology, history and culture of the country (Fig. 8.1). The atlas consists of four volumes: volume 1 – “General characteristics of the territory”; volume 2 – “Nature. Ecology"; volume 3 – “Population. Economy"; volume 4 – “History. Culture".

Rice. 8.1. National Atlas of Russia

The atlas is published in printed and electronic forms (the first three volumes, the electronic version of the fourth volume will be released in 2010).

Cartographic animations– dynamic sequences of electronic maps that convey on the computer screen the dynamics and movement of depicted objects and phenomena in time and space (for example, the movement of precipitation,

moving vehicles, etc.).

We often see animations in everyday life, for example, television weather forecast maps, on which the movements of fronts, areas of high and low pressure, and precipitation are clearly visible.

To create animations, all kinds of sources are used: remote sensing data, economic and statistical data, data from direct field observations (for example, various descriptions, geological profiles, observations of weather stations, census materials, etc.). Dynamic (moving) images of cartographic objects can be different:

− moving the entire map across the screen and individual content elements across the map;

− changing the appearance of conventional signs (size, color, shape, brightness, internal structure). For example, populated areas can be shown as pulsating punches, etc.;

− cartoon sequences frame maps or 3D images. This way you can show the dynamics of glacier melting, the dynamics of the development of erosion processes;

− panning, rotating computer images;

− scaling the image, using the dissolve effect or removing the object;

− creating the effect of movement over the map (flying around, driving around the territory).

Animations can be flat or three-dimensional, stereoscopic and, in addition, can be combined with a photographic image.

Three-dimensional animations combined with a photographic image are called virtual

real maps (the illusion of real terrain is created).

Technologies for creating virtual images can be different. As a rule, first a digital model is created using a topographic map, aerial or satellite image, then a three-dimensional image of the area. It is painted in the colors of the hypsometric scale and then used as a real model.

8.3. Concept of geographic information systems (GIS)

The first geographic information systems were created in Canada, the USA and Sweden to study natural resources. The first GIS appeared in the early 60s. In Canada. The main goal of the Canadian GIS was to analyze Canadian land inventory data. In our country, such research began twenty years later. Currently, in many countries there are various geographic information systems that solve a variety of problems in various industries: in economics, politics, ecology, cadastre, science, etc.

There are dozens of definitions of GIS in the domestic scientific literature.

Geographic Information Systems (GIS) – hardware and software com-

complexes that provide collection, processing, display and distribution of spatial

vein-coordinated data (A.M. Berlyant). One of the functions of GIS is the creation and use of computer (electronic) maps, atlases and other cartographic works.

Geographic information system is an information system designed for collecting, storing, processing, displaying and distributing data, as well as receiving

based on them, new information and knowledge about spatially coordinated objects and phenomena.

The essence of any GIS is that it is used to collect, analyze, systematize, store various information, and create a database. The most convenient form of presenting information to users is cartographic images; in addition, information can be presented in the form of tables, diagrams, graphs, and texts.

A distinctive feature of GIS is that all information in them is presented in the form of electronic maps, which contain information about objects, as well as the spatial reference of objects and phenomena. Electronic maps differ from paper maps in that each symbol (object) depicted on the electronic map corresponds to information entered into the database. This allows you to analyze them in relation to other objects. By pointing the mouse cursor, for example, at a particular area, you can obtain all the information entered about it into the database (Fig. 8.2).

Rice. 8.2. Getting information about an object from the database

In addition, geographic information systems work with map projections, which allows projection transformations of digital and electronic maps

Rice. 8.3. Selecting a map projection in GIS MapInfo Professional

Currently, specialized land geographic information systems, cadastral, environmental and many other GIS have been created.

Using the example of the administrative map of the Tomsk region, we will consider the capabilities of GIS. We have a database that contains information about the size of the areas of the districts of the Tomsk region and the number of residents in each district (Fig. 8.4). Based on these data, we can obtain information about the population density of the Tomsk region; in addition, the program builds a map of population density (Fig. 8.5).

Rice. 8.4. Creating a thematic map based on data entered into the database

Rice. 8.5. Population density map of the Tomsk region, built automatically

Thus, the distinctive features of GIS are:

− geographic (spatial) reference of data;

− storing, manipulating and managing information in a database;

− capabilities for working with projections of geographic information;

− obtaining new information based on existing data;

− reflection of spatio-temporal connections between objects;

− ability to quickly update databases;

− digital relief modeling;

− visualization and data output.

8.3.1. GIS subsystems

GIS consists of a number of blocks, the most important of which are input, processing block

and information output (Fig. 8.6).

Rice. 8.6. GIS structure

Information input block includes the collection of data (texts, maps, photographs, etc.) and devices for converting information into digital form and entering it into computer memory or into a database. Previously, special devices, digitizers, were widely used for this purpose - devices with manual tracing of objects and automatic registration of their coordinates. Currently, they have been completely replaced by automatic devices - scanners. The scanned image is digitized using special software. All characteristics of digitized objects, including statistical data, are entered from the computer keyboard. All digital information goes into a database.

A database is a collection of information organized in such a way that it can be stored on a computer.

Formation of databases, access and work with them is ensured by database management system (DBMS), which allows you to quickly find the required information and carry out its further processing.

Collections of databases and their management tools form data banks.

Information processing unit includes the use of various software that allows you to bind a raster image to a specific coordinate system, select the desired projection, automatically generalize content elements, convert a raster image into a vector image, select image methods, build thematic and topographic maps, combine them with each other, and also design cartographic works.

Information output block– includes devices that allow you to display mapping results, as well as texts, tables, graphs, diagrams, three-dimensional images, etc. These are screens (displays), printing devices (printers), plotters, etc.

GIS for production purposes also includes a map publishing subsystem, which allows you to produce printed forms and print copies of maps.

8.3.2. Organizing data in GIS

The data used in GIS can be very different: the results of geodetic and astronomical observations, field observation data (geological profiles, soil sections, census materials, etc.), various maps, images, statistical data, etc.

Data in GIS have a layer-by-layer organization, i.e. information about objects of the same thematic content is stored in one layer (hydrography, relief, roads, etc.).

Thus, a GIS map consists of a set of information layers (Fig. 8.7). Each layer contains different types of information: areas, points, lines, texts, and together they make up a map.

Distributing objects into layers allows you to quickly edit objects, work with queries, and make various changes. Layers on the map can be managed: swapped, turned off visibility, blocked, frozen, deleted, etc.

When creating a digital map, layers must be arranged in a certain sequence, so when creating a new layer, it is placed in a certain place. The background element layers need to be placed below the line element layers so that they do not obscure the image. The sequence of layer placement conveys the correct overlay of line and background elements of the map.

The number of layers for each map can be different and depends on the purpose of the map and the tasks that will be solved using this map. A very important task is the correct composition of layers and distribution of objects among layers. It should be remembered that a large number of layers can make working with the map difficult.