Digital mapping. Digital cartography. Digital mapping manufacturing processes

Digital maps can be directly perceived by a person, 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 of them (in fact, ways of collecting spatial information):

· Digitization (digitalization) 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 devices of global satellite positioning systems);

· Office processing of field survey data and other methods.

Storage and transmission methods

Since the models describing space (digital maps) are very nontrivial (unlike, for example, raster images), specialized databases (DB, see spatial database) are often used to store them, and not single files of a given format.

For the exchange of digital cards between various information systems, special exchange formats are used. It can be either popular formats of any manufacturers. software(Software) (for example, DXF, MIF, SHP, etc.) that have become the de facto standard, or international standards (for example, the Open Geospatial Consortium (OGC) standard such as GML).

Cartography

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

The objects of cartography are the Earth, celestial bodies, the starry sky and the Universe. The most popular fruits of cartography are figurative-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 how the earth's surface is displayed on a plane. Since the surface of the Earth (approximately spherical, for which the concept of an earthly spheroid is often used) has a certain curvature that is not equal to infinity, it cannot be displayed on a plane while maintaining all spatial relationships simultaneously: angles between directions, distances and areas. Only some of these relationships can be retained. An important concept in mathematical cartography is a cartographic projection, a function that sets 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 cartographic projection (in other words, into a map sheet, which can 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.

Drawing up and design of maps

Compilation and design of maps is an area of ​​cartography, an area of ​​technical design that studies the most adequate ways of displaying cartographic information. This area of ​​cartography is closely interconnected with the psychology of perception, semiotics and similar humanitarian aspects.

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

Digital cartography

Digital (computer) cartography is not so much an independent section of cartography as its tool, due to the modern level of technology development. For example, without canceling the methods of converting coordinates when displaying the Earth's surface on a plane (studied by such a fundamental section as mathematical cartography), digital cartography has changed the way cartographic products are visualized (studied in the section "Drawing up and designing maps").

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

In this case, ACS and Geographic Information Systems (GIS) should not be confused, since their tasks are different. However, in practice, the same set of software is an integrated package used to build both AKC and GIS (prime 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 sown areas 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 necessary fertilizers and calculating the yield. With the help of a GPS-receiver, a field computer and special software (software), you can get electronic maps (contours) of fields with centimeter accuracy!

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

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

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

2. Take into account the resulting yield

3. Calculate the planned consumption of fuels and lubricants

4. Keep 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 (map printing)

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

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

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

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 best choice for accounting for acreage and field history. 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 provides 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-seventh year. This year, the Massachusetts Institute of Technology (USA) produced the first digital elevation and terrain model of the map, which was later used to design highways. This indicates that in cartography from the middle of the twentieth century, new technological mapping and cartographic processes and methods began to develop, which are being improved to the present day. The main directions and tendencies of improvement in them can be distinguished:

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

For a more effective application of scientific and technological processes for 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 their specific tasks. In modern realities, all scientific and industrial sectors, including digital cartography, are guided by the satisfaction of such requests and needs of society. So with the help digital technologies cartography is turning from a cognitive 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 maps, 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.
• visualization tool for images of cartographic products.

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

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

It is worth remembering how the cards were built earlier. Whole staff cartographic groups and thematic parties were created, in the services of which there was a production need. All received survey information was recorded in ink on tracing paper or on a thicker basis. High labor intensity, significant time expenditures 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, convenience in updating and editing maps.

Benefits of digital mapping

Comparing all previous and present possibilities different ways building maps, including the economic component of market efficiency, the following advantages of digital cartography can be distinguished:

• transmission of accurate information about the object, practically eliminating the possibility of receiving errors, due to the use of computer automation in the 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 periodic updating of maps on the same mathematical and geodetic basis.

It should also be noted that digital cartography is increasingly occupying a place in the global information flow, penetrating into various spheres of interesting modern life on the planet and conquering significant layers of users of its products, thereby creating increased demand. This situation occurs as the development progresses:

• new (computer) technologies of cartographic and geoinformation systems;
• new (space) methods of geodetic spatial positioning and determination of 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

In order to obtain certain results in its modern form, digital cartographic production is engaged in the following production processes:

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

Digital mapping manufacturing processes

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

• editorial preparatory period for digital mapping;
• incoming control of raw materials;
• classification of objects of prepared documentation;
• object encodings;
• descriptions of digital map objects;
• editing maps;
• quality control;
• updates;
• conversion to exchange format;
• converting to a given format;
• digitization of map materials;
• vectorization of maps;
• automation of cartographic generalization;
• summary of digital maps;
• control of the card summary;
• transfer of topographic maps to the Foundation.

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 automation of maps
graphic works.

Cartography has now reached a new qualitative level. Due
with the development of computerization, many of the processes of creating maps have completely changed. Poyas
new methods, technologies and directions of mapping have emerged. Can be singled out times
personal areas in which cartography is engaged today: digital cartographer
study, three-dimensional modeling, computer publishing systems, etc. In this regard
new cartographic works appeared: digital, (electronic and virtual)
maps, animations, three-dimensional cartographic models, digital terrain models. Cro
In addition to creating computer maps, the task is to form and maintain databases of a digital cartographer
physical information.

Digital cards are inseparable from traditional cards. The theoretical foundations of the cartographer
money accumulated over the centuries remained the same, only the technical means have changed
creating maps. The use of computer technology has led to significant changes
technologies for creating cartographic products. The technology has been simplified a lot.
completing graphic works: labor-intensive drafting, engraving and other handcrafts have disappeared.
work. As a result, all traditional drawing materials fell out of use.
and accessories. A cartographer with knowledge of software can quickly and efficiently
It is essential to carry out complex cartographic work. There are also many opportunities
carry out design work at a very high level: the design of thematic cards,
atlases covers, title pages, etc.

With the introduction of computer technology, the processes of compiling and preparing
preparation of maps for publication. No need to make high-quality hand-made copies
compilation original (publisher's original). Design original, completed
located on a computer, it makes it very easy to edit and correct proofreading
marking without deteriorating its quality.

The advantages of computer technology are not only perfect quality
graphic works, but also high precision, 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 the creation of digital maps was started in our country at the end of
70s Currently, digital maps and plans are mainly created according to the traditional
original maps and plans, compilation originals, production prints and other
cartographic materials.

Digital cards - digital models of objects presented as encoded
numerical plan coordinates x and y and applicate I.

Digital maps are logical and mathematical descriptions (representations)
mapped objects and relations between them (relations of terrain objects in the
de their combinations, intersections, proximity, different heights in relief, orientation on the side
us light, etc.), formed in the coordinates, projections,
systems of conventional signs, taking into account the rules of generalization and requirements for accuracy. Like
they differ in scale, thematic, spatial coverage, etc. on conventional maps.

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

By content, projection, coordinate system and heights, accuracy and layout, digital
maps and plans must fully meet the requirements for traditional
maps and plans. All digital maps must comply with topological relations.
ness between objects. In the literature, there are several definitions of digital
and electronic maps. Some of them are given in this topic.

Digital card - presentation of map objects in a form that allows com
puter 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 hardcopy or image on screen (V. Haxhold).

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

Electronic atlases- computer analogs of conventional atlases.

Capital atlases are created using traditional methods for a very long time, tens of years.
Therefore, very often, even in the process of creation, their content becomes outdated. Electronic Atlas
sy allow to significantly reduce the time of their production. Maintaining electronic maps
and atlases up to date, their updating is currently being done very quickly
ro and qualitatively.

There are several types of electronic atlases:

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

- Interactive atlases, in which you can change the appearance, image methods
zheniya and classification of mapped phenomena, receive paper copies of maps.

- Analytical atlases (GIS atlases) allowing you to combine and match
maps, quantify and evaluate them, overlay maps
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 by
on behalf of the Government 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 territories
riy "; volume 2 - “Nature. Ecology"; volume 3 - “Population. Economy"; volume 4 - “History.
Culture ".

Rice. 8.1. National Atlas of Russia

Atlas is produced in printing and electronic forms(first three volumes, elec
the throne 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 the displayed
objects and phenomena in time and space (for example, the movement of precipitation,
movement of vehicles, etc.).

We often see animations in everyday life, for example,
TV weather maps showing front movements,
areas of high and low pressure, atmospheric precipitation.

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

Move the entire map around the screen and individual elements content on the map;

The change appearance conventional signs (size, color, shape, brightness, internal
structure). For example, settlements can be shown as pulsating
punsons, etc .;

Cartoon sequences of card frames or 3D images.
This is how you can show the dynamics of glacier melting, the dynamics of the development of erosion processes;

Panning, rotation of computer images;

Scaling an image, using a "Wash" or "Remove" effect
object;

Creation of the effect of movement over the map (flyby, detour of the territory).

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

3D animations combined with a photographic image are called virtual
ny cards(the illusion of a real area is created).

The technologies for creating virtual images can be different. Usually,
first, a digital model is created from a topographic map, aerial or satellite
del, then a three-dimensional image of the area. It is painted in gypsometric colors.
scales and then used as a real model.

8.3. The concept of geographic information systems (GIS)

The first geographic information systems were created in Canada, the USA and Shv ecii for
study of natural resources. The first GIS appeared in the early 60s. In Canada. The main
the purpose of the Canadian GIS was to analyze the land inventory data of Ka
nady. In our country, such studies began twenty years later. At present
time in many countries there are various geographic information systems that
solve a variety of problems in various industries: in economics, politics, ecology,
dastre, science, etc.

There are dozens of GIS definitions in Russian scientific literature.

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

Geographic information system- it is an information system designed for
collection, storage, processing, display and dissemination 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 for collecting, analyzing, sys
thematization, storage of various information, creation of a database. The most convenient form
presenting information to users - cartographic images, in addition,
information can be presented in the form of tables, diagrams, graphs, texts.

A distinctive feature of GIS is that all information in them is presented
on in the form of electronic maps, which contain information about objects, as well as space
natural binding of objects and phenomena. E-cards differ from paper cards
the fact that each conventional sign (object) depicted on electronic map, 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, to a certain area, you can
get all the information entered into the database about him (Fig. 8.2).

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

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

Rice. 8.3. The choice of a cartographic projection in the GIS Mar! N & Pro & 88yupa1

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

Using the example of an administrative card Tomsk region consider the possibilities of GIS.
We have a database that contains information about the size of the area of ​​the districts.
region and the number of inhabitants in each district (Fig. 8.4). Based on this data, we
we can get information about the population density of the Tomsk region, in addition, about
gram builds a population density map (Fig. 8.5).

Rice. 8.4. Creation of a thematic map based on data entered in the database

Rice. 8.5. Population density map of the Tomsk region, built in automatic mode

Thus, distinctive features GIS are:

Geographic (spatial) data referencing;

Storing, manipulating and managing information in the database;

Possibilities for working with projections of geographic information;

Obtaining new information based on available data;

Reflection of spatio-temporal connections between objects;

Ability to quickly update databases;

Digital terrain modeling;

Visualization and data output.

Digital cartography and GIS

In the last decade, cartography has been going through a period of profound changes and technological innovations caused by the informatization of science, industry and society as a whole. It became necessary to revise and redefine many concepts of this scientific discipline. For example, back in 1987 within the International Cartographic Association, two working groups on cartographic definitions and concepts were created. Moreover, one of the main questions to be studied and resolved was the question of whether it is possible to define cartography without the concept of "map" and whether GIS or its elements should be included in this definition. In 1989. The working group proposed the following definition: "Cartography is the organization and communication of geo-referenced information in graphical or digital form; it can include all stages from collection to display and use of data." The concept of "map" is not included in this definition, but it is proposed to consider it separately as a "holistic (i.e., holistic, structural) display and mental abstraction of geographical reality, intended for one or more purposes and transforming the corresponding geographical data into works presented in visual, digital or tactile forms. "

The above definitions caused a wide discussion among cartographers, and as a result, Alternative option definition of cartography, in which it is considered as "the organization, display, communication and use of spatially coordinated information presented in graphic, digital and tactile forms; can include all stages from data collection to their use in the creation of maps or other information spatial documents."

According to most modern cartographers, the technological aspects of cartography are not the main ones in the era of informatics and all definitions of cartography through technology are erroneous. Cartography remains an applied, predominantly visual discipline in which communication aspects are of great importance. It is also wrong to evaluate computer maps in the sense of their similarity, indistinguishability from maps created manually. The real significance of GIS technology lies precisely in the possibility of creating works of a new type. With all this, the main task of cartography remains the knowledge of the real world, and here it is very difficult to separate the form (cartographic display) from the content (reflected reality). The progress of geoinformation technologies has only increased the range of data to be mapped, expanded the range of scientific disciplines that need cartography. On-screen (display) maps and electronic atlases, which are now becoming part of national cartographic programs in many countries, only strengthen the relationship of cartography with computer graphics and GIS, without, however, changing the essence of cartography.

It should be noted that digital cartography is genetically not a direct continuation of traditional (paper) cartography. It has evolved in the course of the general development of GIS software and therefore is often viewed as a secondary GIS component, which, unlike GIS software, does not require large investments. For example, an untrained user using existing GIS software after a few days of training can already create a simple digital map, but even in a month he is not able to create a workable GIS software. On the other hand, as noted by cartographers, due to the apparent lightness and simplicity, digital cartography is underestimated with all the ensuing consequences.

Digital cartography has taken on a life of its own, and its connection with traditional cartography is often viewed as completely redundant. As you know, to create a traditional paper map requires rather sophisticated equipment, as well as a team of experienced specialists (cartographers-designers), creating and editing maps, performing routine work on processing the primary material. This is a technically and technologically very complex and time-consuming process. On the other hand, all you need to do to create a digital map is Personal Computer, external devices, software and source (generally paper) card. In other words, any user gets the opportunity to create digital maps in the form finished products- digital cards for sale. As a result, many non-professionals are currently employed in digital mapping, and the separation from the theory and methodology of traditional cartography leads to a loss in the quality of transmission of geometric and topological forms of map objects, because the ability to draw well on paper is not enough for high-quality digitalization (digitization is a more complicated process, as how it is necessary to qualitatively approximate continuous curves by line segments). At the same time, the quality of the design suffers: often the maps printed out "resemble a drawing with a set of color spots, but not a map."

Only recently, with the development of the GIS market, the need for high-quality digital maps has begun to increase; users began to pay attention not only to the speed of digitizing cards and their low price but also on quality. The number of places where specialists are trained using GIS technology is growing; Western systems are being Russified and Ukrainianized, expanding the circle of potential GIS users. Thus, there is a tendency for the qualitative development of digital cartography in the wake of the general development of GIS technology.

Let's consider some of the features of digital mapping technology and the main parameters of digital maps. First of all, it should be noted that due to the variety of tasks solved with the help of digital maps, it is difficult to unambiguously determine the universal criteria for their quality, therefore, the most general criterion should be the ability to provide a solution to the task. At the moment, the situation on the market for digital maps is such that they are mainly created for a specific project, in contrast to traditional cartography, where already existing cartographic materials are used as a cartographic base. Therefore, most often the creation of a digital map is determined not by established and time-tested instructions, but by scattered and not always professionally drawn up technical specifications.

Digital map quality

The quality of a digital map consists of a number of components, but the main ones are informational content, accuracy, completeness and correctness of the internal structure.

Informativeness. A map as a model of reality has epistemological properties, for example, such as content-based correspondence (scientifically grounded reflection of the main features of reality), abstractness (generalization, transition from individual concepts to collective ones, selection of typical characteristics of objects and elimination of secondary ones), spatio-temporal similarity (geometric similarity of sizes and shapes, temporary similarity and similarity of relations, connections, subordination of objects), selectivity and synthetics (separate presentation of jointly manifested phenomena and factors, as well as a single holistic image of phenomena and processes that appear separately in real conditions). These properties, of course, also affect the quality of the final product - a digital map, however, they mainly relate to the competence of the creators of the original cartographic work: the creators of a traditional source map are responsible for its information content, and when creating a digital map, it is important to choose this source correctly and correctly transfer , taking into account the peculiarities of digital mapping, the information included in the original map.

Completeness Content transfers. The value of this parameter depends mainly on the technology for creating a digital map, that is, on how strictly control of passes by operators of digital objects is carried out. For control, a hard copy of a digital card, printed on plastic in the original scale, can be used. With the subsequent imposition on the digitizing source, the content of the digital map and the source material are verified. This method can also be used to assess the quality of the transfer of object shapes, but it is unacceptable for assessing the error in the position of the contours, since the output device always gives noticeable distortions. When vectorizing a raster, combining the layers of the created digital map and the raster background allows you to quickly identify the missing objects.

Accuracy. The concept of the accuracy of a digital map includes such parameters as the error in the position of the contours relative to the source, the accuracy of transferring the sizes and shapes of objects during digitalization, as well as the error in the position of the contours of the digital map relative to the terrain associated with the source of digital mapping (paper deformation, distortion of the raster image during scanning, etc. etc.). In addition, accuracy depends on software, hardware used, and digital source. At the moment, two technologies for digitizing maps exist in parallel and complement each other - digitizer input and raster digitization (scanning). Practice shows that now it is difficult to talk about the advantage of any one of them. When digitizing digitizing, the main volume of work on entering digital maps is performed by the operator in manual mode, that is, to enter an object, the operator hovers the cursor over each selected point and presses a button. The accuracy of the digital input is critically dependent on the qualifications of the operator. When vectorizing raster maps, subjective factors influence less, since the raster substrate allows you to correct the input all the time, however, the quality of the raster affects the transfer of the shape of objects, and when the edges of the raster line are jagged, bends of the drawn vector line begin to appear, which are caused not by the general shape of the line, but by local violations raster.

The correctness of the internal structure.

The finished digital card must have the correct internal structure, determined by the requirements for cards of this type... For example, the core of the cartographic subsystem in GIS using digital vector maps is a multilayer structure of maps (layers), over which operations of end-to-end search should be performed, overlay operations with the creation of derived digital maps and maintaining the connection of object identifiers of the source and derived maps. To support these operations, requirements are imposed on the topological structure of digital maps in GIS that are much more stringent than, for example, for maps that are used to solve problems of automated mapping or navigation. This is due to the fact that the contours of objects from different maps (layers) must be strictly coordinated, although in practice, despite the sufficiently accurate digitization of the source maps separately, this alignment is not achieved, and when overlapping digital maps, false polygons and arcs are formed. Discrepancies can be visually indistinguishable up to a certain magnification scale, which is quite acceptable for automated mapping tasks focused on the creation of traditional maps of a fixed scale using a computer. However, this is completely unacceptable for the functioning of GIS, when a rigorous mathematical apparatus is used to solve various problems of analysis. For example, a topological map must have a correct line-node (polygons must be assembled from arcs, arcs must be connected at nodes, etc.) and a multilayer structure (the corresponding boundaries from different layers coincide, the arcs of one layer are precisely adjacent to the objects of another, etc.) . e). The creation of the correct structure of a digital map depends on the capabilities of the software and on the digital technology.

Currently, a whole digital mapping industry has already formed in the world, and an extensive market for digital maps and atlases has emerged. The first successful commercial project here, apparently, should be considered the Digital Atlas of the World (manufactured by Delorme Mapping Systems), released in 1988. This was followed by the British Domesday Project / 100 /, which resulted in the creation of a digital atlas of Great Britain at optical discs(materials of military topographic survey were used as initial maps and topographic bases). Since 1992, the Cartographic Agency of the US Department of Defense has been producing and correcting the Digital Chart of the World (DCW) at a scale of 1: 1,000,000. National digital atlases and general geographic maps have already been created in many countries of the world. In Fig. 5.1 presents a black-and-white version of a printout of one of the fragments of the digital atlas of the world.

Digital cartography - 3.7 out of 5 based on 6 votes

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 automating cartographic work.

Cartography has now reached a new qualitative level. In connection with the development of computerization, many of the processes of creating maps have completely changed. New methods, technologies and directions of mapping have appeared. It is possible to single out various areas in which cartography is engaged 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, the task is to form and maintain databases of digital cartographic information.

Digital cards are inseparable from traditional cards. The theoretical foundations of cartography, accumulated over the 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 of creating cartographic works. The technology of performing graphic works has become much simpler: labor-intensive drawing, engraving and others have disappeared. handicraft... As a result, all traditional drawing materials and accessories have become obsolete. A cartographer with knowledge of the software can quickly and efficiently perform complex cartographic work. Also, there are many opportunities to perform design work at a very high level: the design of thematic maps, atlase covers, title pages, etc.

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

The advantages of computer technology are not only the ideal quality of graphic works, 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 the creation of digital maps was started in our country in the late 70s. At present, digital maps and plans are mainly created from traditional originals of maps and plans, compilation originals, production prints and other cartographic materials.

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

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

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

In terms of content, projection, coordinate system and heights, accuracy and layout, digital maps and plans must fully meet the requirements for traditional maps and plans. All digital maps must respect the 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 objects 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 a screen (W. Haxhold).

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

Electronic atlases- computer analogs of conventional atlases.

Capital atlases are created using traditional methods for a very long time, tens of years. Therefore, very often, even in the process of creation, their content becomes outdated. Electronic atlases can significantly reduce the time of their production. Maintaining electronic maps and atlases up to date, updating them is currently 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, image methods and classification of the mapped phenomena, receive paper copies of maps.

Analytical atlases(GIS atlases) that allow you to combine and correlate maps, quantify and evaluate them, and overlay maps.

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 provides a comprehensive view 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 the depicted objects and phenomena in time and space (for example, the movement of precipitation,

movement of 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, atmospheric precipitation are clearly visible.

To create animations, all kinds of sources are used: remote sensing data, economic and statistical data, data of direct field observations (for example, various descriptions, geological profiles, observations of meteorological 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, settlements can be shown as pulsating punches, etc .;

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

− panning, rotation of computer images;

− scaling the image, using the effect of "dissipation" or removal of the object;

− creating the effect of movement over the map (flyby, detour of the territory).

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

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

ny maps (creates the illusion of real terrain).

The 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. The concept of geographic information systems (GIS)

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

There are dozens of GIS definitions in Russian scientific literature.

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

plexes that provide collection, processing, display and distribution of space

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

Geographic information system Is an information system designed to collect, store, process, display and distribute data, as well as receive

on their basis, new information and knowledge about spatially coordinated objects and phenomena.

The essence of any GIS lies in the fact that it is used to collect, analyze, organize, 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 that contain information about objects, as well as the spatial reference of objects and phenomena. Electronic maps differ from paper maps in that each conventional symbol (object) depicted on the electronic map corresponds to the information entered in the database. This allows you to analyze them in relation to other objects. Pointing with the mouse cursor, for example, to any area, you can get all the information entered about it in the database (Fig. 8.2).

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

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

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

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

On the example of the administrative map of the Tomsk region, we will consider the possibilities of GIS. We have a database that contains information about the size of the area of ​​districts of the Tomsk region and the number of inhabitants 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 population density map (Fig. 8.5).

Rice. 8.4. Creation of a thematic map based on data entered in the database

Rice. 8.5. Population density map of the Tomsk region, built in automatic mode

Thus, the distinctive features of GIS are:

− geographic (spatial) data referencing;

− storing, manipulating and managing information in the database;

− the ability to work with projections of geographic information;

− obtaining new information based on existing data;

- reflection of spatio-temporal connections between objects;

− the ability to quickly update databases;

− digital terrain 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 unit

and information output (fig. 8.6).

Rice. 8.6. GIS structure

Information input block includes the collection of data (texts, maps, pictures, etc.) and devices for converting information into digital form and entering it into computer memory or a database. Previously, for this purpose, special digitizer devices were widely used - devices with manual tracing of objects and automatic registration of their coordinates. Nowadays they are completely replaced by automatic devices - scanners. The scanned image is digitized using special software. All characteristics of the objects being numbered, including statistical data, are entered from the computer keyboard. All digital information goes into the 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 provides database management system (DBMS), which allows you to quickly find the required information and carry out its further processing.

Collections of databases and tools for their management form data banks.

Information processing unit involves the use of various software that allows you to bind bitmap to a specific coordinate system, select the desired projection, carry out automatic generalization of content elements, convert a raster image into a vector one, select image methods, build thematic and topographic maps, combine them with each other, and also design cartographic products.

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

GIS for industrial purposes also includes a subsystem for publishing maps, which allows you to make printed forms and to carry out printing of circulation of cards.

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 profiles, census materials, etc.), various maps, images, statistical data, etc.

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

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

Distributing objects to layers allows you to quickly edit objects, work with queries, and make various changes. The layers on the map can be controlled: swap positions, turn off visibility, block, freeze, delete, etc.

When designing a digital map, the layers must be arranged in a certain sequence, therefore, when creating a new layer, it is placed in a certain place. The background layers must be placed below the hatch layers so that they do not obscure the image. The sequence of placing layers conveys the correct overlay of hatch 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 for this map. A very important task is the correct composition of layers and the distribution of objects in layers. It should be remembered that a large number of layers can make it difficult to work with the map.