What is GIS technology? Geographic information systems What is GIS in geography

GIS is a modern geographic information system mobile systems, which have the ability to display their location on the map. This important property is based on the use of two technologies: geoinformation and If a mobile device has a built-in GPS receiver, then with the help of such a device it is possible to determine its location and, therefore, the exact coordinates of the GIS itself. Unfortunately, geo information Technology and systems in the Russian-language scientific literature are represented by a small number of publications, as a result of which there is almost no information about the algorithms underlying their functionality.

GIS classification

The division of geographic information systems occurs on a territorial basis:

Global GIS has been used to prevent man-made and natural disasters since 1997. Thanks to this data, it is possible in a relatively short time to predict the scale of the disaster, draw up a plan for eliminating the consequences, assess the damage caused and human losses, and organize humanitarian actions.
Regional geographic information system developed at the municipal level. It allows local authorities to predict the development of a certain region. This system reflects almost all important areas, such as investment, property, navigation and information, legal, etc. It is also worth noting that thanks to the use of these technologies, it has become possible to act as a guarantor of the life safety of the entire population. The regional geographic information system is currently being used quite effectively, helping to attract investment and the rapid growth of the region's economy.

Each of the above groups has certain subtypes:

Global GIS includes national and subcontinental systems, usually with state status.
In the regional - local, subregional, local.

Information about these information systems can be found in special sections of the network called geoportals. They are posted in the public domain for review without any restrictions.

Principle of operation

Geographic information systems work on the principle of compiling and developing an algorithm. It is this that allows you to display the movement of an object on a GIS map, including the movement of a mobile device within the local system. To depict a given point on a terrain drawing, you need to know at least two coordinates - X and Y. When displaying the movement of an object on a map, you will need to determine the sequence of coordinates (Xk and Yk). Their indicators must correspond to different points in time of the local GIS system. This is the basis for determining the location of the object.

This sequence of coordinates can be extracted from a standard NMEA file of a GPS receiver that has performed real movement on the ground. Thus, the algorithm considered here is based on the use of NMEA file data with the coordinates of an object’s trajectory over a certain territory. The necessary data can also be obtained by modeling the movement process based on computer experiments.

GIS Algorithms

Geographic information systems are built on initial data that is taken to develop an algorithm. As a rule, this is a set of coordinates (Xk and Yk) corresponding to a certain trajectory of the object in the form of an NMEA file and a GIS digital map of a selected area. The task is to develop an algorithm that displays the movement of a point object. In the course of this work, three algorithms underlying the solution of the problem were analyzed.

The first GIS algorithm is the analysis of NMEA file data in order to extract from it a sequence of coordinates (Xk and Yk),
The second algorithm is used to calculate the path angle of the object, while the parameter is counted from the direction to the east.
The third algorithm is for determining the course of an object relative to the cardinal points.

Generalized algorithm: general concept

The generalized algorithm for displaying the movement of a point object on a GIS map includes the three previously mentioned algorithms:

NMEA data analysis;
calculating the path angle of an object;
determining the course of an object relative to countries around the globe.

Geographic information systems with a generalized algorithm are equipped with a main control element - a timer. Its standard purpose is that it allows the program to generate events at certain intervals. Using such an object, you can set the required period for executing a set of procedures or functions. For example, to repeatedly count a time interval of one second, you need to set the following timer properties:

Timer.Interval = 1000;
Timer.Enabled = True.

As a result, every second the procedure for reading the X, Y coordinates of the object from the NMEA file will be launched, as a result of which this point with the obtained coordinates is displayed on the GIS map.

How the timer works

The use of geographic information systems occurs as follows:

Three points are marked on the digital map ( symbol- 1, 2, 3), which correspond to the trajectory of the object at various times tk2, tk1, tk. They must be connected by a solid line.
Turning on and off the timer that controls the display of the movement of an object on the map is carried out using buttons pressed by the user. Their meaning and a certain combination can be studied according to the diagram.

NMEA file

Let us briefly describe the composition of the NMEA GIS file. This is a document written in ASCII format. Essentially, it is a protocol for exchanging information between a GPS receiver and other devices, such as a PC or PDA. Each NMEA message begins with a $ sign, followed by a two-character device designator (for a GPS receiver, GP), and ends with the sequence \r\n, a carriage return and line feed character. The accuracy of the information in the notification depends on the type of message. All information is contained on one line, with fields separated by commas.

In order to understand how geographic information systems work, it is enough to study the widely used $GPRMC message, which contains a minimal but basic set of data: the location of an object, its speed and time.
Let's look at a specific example to see what information is encoded in it:

date of determination of object coordinates - January 7, 2015;
universal time UTC coordinates determination - 10h 54m 52s;
object coordinates - 55°22.4271" N and 36°44.1610" E.

We emphasize that the coordinates of the object are presented in degrees and minutes, and the latter indicator is given with an accuracy of four decimal places (or a dot as a separator of the integer and fractional parts of a real number in the USA format). In the future, you will need the fact that in the NMEA file the latitude of the object’s location is in the position after the third comma, and the longitude is after the fifth. At the end of the message, it is transmitted after the symbol "*" in the form of two hexadecimal digits - 6C.

Geographic information systems: examples of compiling an algorithm

Let's consider an algorithm for analyzing an NMEA file in order to extract a set of coordinates (X and Yk) corresponding to the object. It is composed of several successive steps.

Determining the Y coordinate of an object

NMEA Data Analysis Algorithm

Step 2. Find the position of the third comma in the line (q).

Step 3. Find the position of the fourth comma in the line (r).

Step 4. Find, starting at position q, the decimal point symbol (t).

Step 5. Extract one character from the string located at position (r+1).

Step 6. If this symbol is equal to W, then the NorthernHemisphere variable gets the value 1, otherwise -1.

Step 7. Extract (r-+2) characters of the string starting at position (t-2).

Step 8. Extract (t-q-3) characters of the string starting at position (q+1).

Step 9. Convert strings to real numbers and calculate the Y coordinate of the object in radian measure.

Determining the X coordinate of an object

Step 10. Find the position of the fifth comma in the line (n).

Step 11. Find the position of the sixth comma in line (m).

Step 12. Find, starting at position n, the decimal point symbol (p).

Step 13. Extract one character from the string located at position (m+1).

Step 14. If this character is "E", then the EasternHemisphere variable gets the value 1, otherwise -1.

Step 15. Extract (m-p+2) characters of the string starting at position (p-2).

Step 16. Extract (p-n+2) characters of the string, starting at position (n+1).

Step 17. Convert the strings to real numbers and calculate the X coordinate of the object in radian measure.

Step 18. If the NMEA file is not fully read, then go to step 1, otherwise go to step 19.

Step 19. Finish the algorithm.

Steps 6 and 16 of this algorithm use the variables NorthernHemisphere and EasternHemisphere to numerically encode the location of an object on Earth. In the northern (southern) hemisphere, the NorthernHemisphere variable takes the value 1 (-1), respectively, similarly in the eastern EasternHemisphere - 1 (-1).

Application of GIS

The use of geographic information systems is widespread in many areas:

geology and cartography;
trade and services;
cadastre;
economics and management;
defense;
engineering;
education, etc.

Cadastral engineers, designers, geologists and other specialists are often faced with the need to use cartographic data in their work. Modern developments make it possible to receive satellite images of the area in the smallest detail, and specially created software– use this information for analytical purposes and display it in the required format.

Let's talk about structures that allow us to generalize and study geographical material in order to implement the most reasonable and optimal measures in each specific case.

Definition of GIS (GIS): what the abbreviation stands for and what it is

Geographic information systems (GIS) are advanced computer technologies that are used to create maps and evaluate actually existing objects, as well as incidents occurring in the world. In this case, visualization and spatial overviews are combined with standard database processes: entering information and obtaining statistical results.

It is the indicated characteristics that allow these programs to be widely used to solve many problems:

Analysis of physical phenomena and events on the planet.

Understanding and identifying their main causes.

Study of the issue of overpopulation.

Planning long-term solutions in urban planning.

Assessing the results of current business activities.

Environmental problems - pollution of areas, reduction in the size of forests.

In addition to global goals, with the help of such support it is possible to regulate specific situations, for example:

Finding the optimal path between points.

Choosing a convenient location for the company.

Finding the desired building by address.

Municipal tasks.

Geographical analysis is not a newly emerging area. But the technologies we are considering best meet the requirements of our time. This is the most efficient, effective and convenient process that automates the procedure for collecting relevant material and processing it.

Today, geographic information systems are a profitable field of activity that employs millions of people in different countries. In Russia alone, more than 200 different companies are developing and implementing such technologies in all areas of business.

It has several components.

Equipment. These are various types of computer platforms, from personal machines to global centralized servers.

Software. All the necessary tools for obtaining, processing and visualizing material are present here. Separate components can be used to designate components for:

Introduction and manipulation of information;

Database management (DBMS);

Mapping spatial queries;

Access (interface).

What manipulations are possible in programs?

The utilities perform several processes:

Enter. In this case, the material is converted into the required digital format. During digitization, paper maps are taken as a basis and processed using scanners. This is relevant for large objects; for small tasks you can enter information through a digitizer.

Manipulation. Technologies have different ways of modifying materials and designating certain parts necessary to perform the immediate task. For example, they allow you to reduce the scale of different elements to a single value for further general processing.

Control. With a significant amount of information and a large number of users, it is rational to use database management systems to collect and structure the material. Most often, the relational model is used when information is stored in tables.

Query and analysis. The program allows you to get answers to many primitive and more detailed questions, ranging from the identity of the owner of the site to the predominant types of soil under the mixed object. It is also possible to create templates for finding a specific type of request. Tools such as proximity assessment and overlap studies are used for analysis.

Visualization. This is the desired result of most spatial actions. The cards are equipped with accompanying documentation, three-dimensional images, tabular values and graphs, multimedia and photographic reports.

Types of GIS

The classification of geographic information systems is based on the principle of territory coverage:

Global(national and subcontinental) - provide an opportunity to assess the situation on a planetary scale. Thanks to this, it is possible to predict and prevent natural and man-made disasters, assess the size of the disaster, plan the elimination of consequences and organize humanitarian assistance. Used all over the world since 1997.

Regional(local, subregional, local) - operate at the municipal level. Such technologies reflect many key areas: investment, property, navigation, public safety and others. They help make decisions when developing a particular area, which helps attract capital to it and grow its economy.

GIS stores factual information about objects in the form of a collection of thematic layers, united by geographic location. This approach provides solutions to diverse problems in reorganizing the area and carrying out events.

To find the location of an object, the coordinates of the point, its address, index, land plot number, etc. are used. This information is applied to maps after the geocoding procedure.

Technologies can work with raster and vector models.

IN vector form the material is encoded and stored as a set of coordinates. It is more suitable for stable elements with constant properties: rivers, pipelines, landfills.

Raster scheme includes blocks of information about individual components. It is adapted to work with variable characteristics, such as soil types and site accessibility.

Related Innovations

GIS interacts closely with other applications. Let's consider the connection and main differences with similar information technologies.

DBMS. They serve to accumulate, store and coordinate various materials, therefore they are often included in software support for geographic systems. Unlike the latter, they do not have tools for assessing and spatially depicting data.

Desktop mapping tools. Maps are used as information, but they have limited capabilities for managing and analyzing them.

Remote sensing and GPS. Here, information is collected using special sensors: on-board cameras of aircraft, global positioning sensors and others. In this case, the material is collected in the form of pictures with the implementation of their processing and study. However, due to the lack of some tools, they cannot be considered geographic information systems.

CAD These are programs for drawing up various drawings, floor plans and architectural designs. They use a set of elements with fixed parameters. Many of them have the ability to import values from GIS.

Among such utilities, it is worth noting the products of ZWSOFT:

A powerful and affordable GIS for importing, exporting, and managing geospatial data. When selected for use with ZWCAD/AutoCAD, the application runs within the CAD platform and allows users to exchange geospatial data between platform drawing and GIS files, GIS servers or GIS data stores, load vector and raster maps and underlays, and manage attribute data and tables data.

– analogue of GeoniCS. Allows you to automate design and survey work. In this case, drawings are created that comply with current design regulations and standards. Contains six modules, the use of which solves various engineering, including geological, problems.

– analogue of GeoniCS Surveys. Analyzes and interprets the results of laboratory and field research, performs statistical processing according to specified parameters, calculates various standard and design indicators, and generates reporting according to the standards of the CIS countries.

– utility for cadastral engineers with a full set of tools that automate the preparation of documents. Constant updating allows you to always provide up-to-date information on paperwork in accordance with the requirements of the inspection authorities.

– computer-aided design system for architects, engineers, designers. It has a new core based on hybrid technologies, combining a clear interface, Unicode support, and the ability to create three-dimensional models based on their sections. It has a built-in ability to insert raster maps using georeference files (geographic registration).

GIS examples for beginners

There are a lot of programs created for the purposes of such geographic analysis. Let's look at some of them as an example.

Mapinfo

The main functionality is:

use of a clear and convenient exchange scheme for transferring data to other structures;

the active window can be saved in different formats: bmp, tif, jpg and wmf;

support for a significant number of geographic projections and coordinate systems;

You can enter material through a digitizer.

Using the utility, you can make thematic maps and build 3D landscapes.

DataGraph

A tool for spatial visualization, modeling situations, constructing synthetic indicators. Optimal for learning the basics of computer cartography in educational institutions.

The program allows you to:

create vector maps;

link an unlimited number of thematic databases to each element;

copy data to another file via the clipboard;

manually change the characteristics of objects and their locations.

A simple tool for mastering the basic level. Solve primarily illustrative problems. Allows you to create digitized maps based on a regular image and in any graphic format.

Application of GIS

The possibilities for using geographic technologies are vast. Among the areas where these systems are most applicable are:

Land management. Utilities needed for compiling cadastres, calculating the areas of elements, marking the boundaries of land plots.

Managing the placement of objects. Here their use is relevant for constructing an architectural plan, coordinating a network of industrial, retail and other special-purpose points.

Regional development. Engineering surveys of specific locations, solutions to problems of optimizing infrastructure and attracting investors are currently impossible without a detailed study using such structures.

Protection of Nature. The programs allow for environmental monitoring and resource use planning.

Emergency forecasting. Tracking changes in different geological conditions makes it possible to predict the possibility of disasters, develop measures to prevent them and minimize losses from them.

Brief summary

We gave a decoding of the concept of GIS, examined in detail what geographic information systems are and where they are used. In conclusion, we will say that this is a very promising direction that is actively developing. Without the use of such technologies, it is no longer possible to imagine the work of specialists in many fields.

Geographic information systems (GIS) are automated systems whose functions are the collection, storage, integration, analysis and graphical interpretation of spatiotemporal data, as well as associated attribute information about objects presented in GIS.

GIS appeared in the 1960s with the advent of information processing technologies in DBMS and visualization of graphic data in CAD, automated map production, and network management.

The purpose of a GIS is determined by the tasks it solves (scientific and applied), such as resource inventory, management and planning, and decision support.

Stages of creating a GIS:

Pre-design research, including studying user requirements and functionality of the software used,

Feasibility Study (TES)

Profitability assessment,

GIS system design, including the pilot project stage, GIS development;

Testing GIS on a small territorial fragment or test area or creating a prototype,

Introduction of GIS;

Operation and maintenance of GIS.

Data sources for creating GIS:

Base layer - cartographic materials (topographic and general geographic maps, maps of administrative-territorial divisions, cadastral plans, etc.), used in the form of a geodetic coordinate system and flat rectangular coordinates of cartographic projections of source materials, geodetic coordinates and projections of created base maps, on the basis of which the construction of digital models in GIS and all their tasks are practically implemented.

Remote sensing data (RSD): including materials received from spacecraft and satellites. Images are received and transmitted to Earth from imaging equipment located in different orbits. The resulting images are distinguished by different levels of visibility and detail in displaying objects of the natural environment in several spectral ranges (visible and near-infrared, thermal infrared and radio range), which makes it possible to solve a wide range of environmental problems. Remote sensing methods also include aerial and ground surveys, and other non-contact methods, such as hydroacoustic surveys of the seabed topography. Materials from such surveys provide both quantitative and qualitative information about various objects of the natural environment;

The results of geodetic measurements on the ground, performed by levels, theodolites, electronic tacheometers, GPS receivers and etc;

Data from state statistical services for a variety of sectors of the national economy, as well as data from stationary measuring observation posts (hydrological and meteorological data, information on environmental pollution, etc.).

Literary data (reference publications, books, monographs and articles containing a variety of information on certain types of geographical objects). In GIS, only one type of data is rarely used; most often it is a combination of various data for any territory.

Effective use of GIS to solve a variety of spatially localized problems requires the user to have a sufficient amount of knowledge about geodetic coordinate systems, cartographic projections and other elements of the mathematical basis of GIS maps, knowledge about methods for obtaining from a map various information, mathematical and other methods of using this information to solve spatially localized GIS problems.

The scientific, technical, technological and applied aspects of the design, creation and use of GIS are studied by geoinformatics.

Data collected in geoinformatics is classified into a special class of data called geodata.

Geodata is data about objects, forms of territory and infrastructures on the surface of the Earth, and spatial relationships must be present as an essential element in them.

Geodata describes objects through their position in space directly (for example, coordinates) or indirectly (for example, connections).

In general, the following technologies for data collection in geoinformatics should be highlighted:

Aerial photography, which includes aerial photography, shooting from minicarriers;

Global Positioning System (GPS);

Satellite imagery, which is one of the most important sources of data for GIS when conducting natural resource research, environmental monitoring, assessment of agricultural and forest land, etc.;

Maps or cartographic information, which is the basis for building digital GIS models;

Data received via the Internet;

Ground photogrammetric survey serves as a source of information for GIS in the analysis of urban situations, environmental monitoring of deformation and precipitation;

Digital photogrammetric surveying is based on the use of digital photogrammetric cameras, which allow information to be digitally output directly to a computer;

Videography, as a source of data for GIS, is used mainly for monitoring purposes;

Documents, including archival tables and coordinate catalogs, serve as the main source of data for entering so-called subject or thematic information into GIS, which includes economic, statistical, sociological and other types of data;

Geodetic methods (automated and non-automated) are used to clarify coordinate data,

The source of data for GIS is also the results of processing in other GIS;

Photographs, drawings, drawings, diagrams, video images and sounds;

Statistical tables and text descriptions, technical data;

Postal addresses, phone books and reference books;

Geodetic, environmental and any other information.

GIS is used to solve scientific and applied problems of infrastructure design, urban and regional planning, rational use of natural resources, monitoring environmental situations, taking prompt measures in emergency situations, etc.

GIS are classified according to the following criteria:

1. By functionality:

Fully functional general purpose GIS;

Specialized GIS, focused on solving a specific problem in any subject area;

Information and reference systems for home and information and reference use. The functionality of GIS is also determined by the architectural principle of its construction:

Closed systems do not have expansion capabilities; they are capable of performing only the set of functions that are clearly defined at the time of purchase; - open systems are distinguished by ease of adaptation and expansion capabilities, since they can be completed by the user himself using a special device (built-in programming languages).

2. According to spatial (territorial) coverage, GIS are divided into global (planetary), national, regional, local (including municipal).

3. According to problem-thematic orientation - general geographic, environmental and environmental management, sectoral (water resources, forestry, geological, tourism, etc.).

4.By the method of organizing geographic data - vector, raster, vector-raster GIS.

The GIS structure includes a complex technical means(CTS) and software (SW), information support (IS).

CTS is a complex of hardware, including a workstation ( Personal Computer), information input/output devices, data processing and storage devices, telecommunications.

The workstation is used to manage the operation of the GIS and perform data processing processes based on computational and logical operations.

Data entry is carried out using various technical means and methods: directly from the keyboard, using a digitizer or scanner, through external computer systems. Spatial data can be obtained from electronic surveying instruments, using a digitizer or scanner, or using photogrammetric instruments.

Devices for processing and storing data are integrated into the computer system unit, which includes a central processor, RAM, storage devices (hard drives, portable magnetic and optical storage media, memory cards, flash drives, etc.). Data output devices - monitor, plotter, plotter, printer, which provide a visual representation of the results of processing spatio-temporal data.

Software - provides the implementation of GIS functionality. It is divided into basic and application software.

Basic software includes OS(OS), software environments, network software, database management systems, and modules for managing data input and output facilities, a data visualization system and modules for performing spatial analysis.

Application software -software, designed to solve specialized problems in a specific subject area. They are implemented in the form of separate modules (applications) and utilities (auxiliary tools).

IO is a collection of information arrays, systems of coding and classification of information.

A feature of storing spatial data in GIS is its division into layers.

The multilayer organization of an electronic map, with a flexible layer management mechanism, allows you to combine and display a much larger amount of information than on a regular map.

Information presented in the form of separate layers and their joint analysis in different combinations makes it possible to obtain additional information in the form of derived layers with their cartographic display (in the form of isolinear maps, combined maps of various indicators, etc.).

GIS technology combines disparate data into a single view, which simplifies the adoption of management decisions on information support at various levels of planning and obtaining, analyzing and making decisions in science and business management.

The GIS market, which differs in functionality, requirements for CTS, software and information technology, is quite developed.

Software is one of the few industries where the Russian Federation competes on equal terms with the West.

GIS among information technologies

The first question of a person unfamiliar with geographic information systems (GIS) will, of course, be: “Why do I need this?” Indeed, we rarely use atlases and maps in our lives. And in general, geography, as is known from the works of the classics, is also not necessary to study - there are cab drivers for that. In addition, we already receive more information, and not always pleasant information, from various sources than we would sometimes like. And does it still need to be systematized? There's a lot to think about here. But, if you look at it, GIS is more than a map transferred to a computer. So what is it and what is it eaten with?

But, unfortunately, with a brief, understandable to everyone and, as Professor Preobrazhensky from “Heart of a Dog” said, “factual” definition, everything is not so simple. The point, apparently, is that this technology, firstly, is largely universal, and secondly, it is developing so quickly and capturing new areas of life and activity that, as in an anecdote from the times of developed socialism, products (i.e. definitions) they don’t have time to deliver. The authors of each new fundamental book on GIS (and such books are constantly being published), and even more so of numerous monographs relating to one of the countless areas of their application, try to make their feasible contribution to the creation of such a definition. We refer you to these books if you want to find the most acceptable definition for you. Everyone who plunges into this world is free to give their own. We, without in any way claiming originality, will take what is already available.

Here, for example, are two definitions: one “lyrical”, the other “practical”. First: “This is an opportunity for a new look at the world around us.” Second: “GIS is a modern computer technology for mapping and analyzing objects in the real world, as well as events occurring on our planet, in our lives and activities.”

Without any definitions and just a description, this technology combines traditional database operations, such as querying and statistical analysis, with the benefits of rich visualization and geographic (spatial) analysis that a map provides. These capabilities distinguish GIS from other information systems and provide unique prospects for its use in a wide range of tasks related to the analysis and forecast of phenomena and events in the surrounding world, with the understanding and identification of the main factors and causes, as well as their possible consequences, with the planning of strategic decisions and the ongoing consequences of the actions taken.

One of the best ways learn what GIS is - see how other people use this technology. Well, then, without delay, start working with GIS and demonstrate your achievements to others. Any person with a creative attitude to business, when they see the possibilities of GIS, their hands immediately begin to itch... After all, GIS is also a toolkit with the help of which you can solve problems for which sometimes there are no ready-made complete solutions.

But let's go back to the beginning. At first glance, the only obvious thing is the use of GIS in the preparation and printing of maps and, perhaps, in the processing of aerial and satellite images. The real range of applications of GIS is much wider, and to appreciate it, we should look at the use of computers in general: then the place of GIS will be much clearer.

Computers not only provide great convenience for performing well-known operations with documents - they are the carriers of a new direction of human activity. This direction is information technology, and it is on them that modern society is largely based. What is it - information technology?

The term “information” is often understood too narrowly (like the “information” that journalists report). In reality, everything that can be represented in the form of letters, numbers and images should be called information. So, all the methods, techniques, techniques, means, systems, theories, directions, etc. etc., which are aimed at collecting, processing and using information, are collectively called information technologies. And GIS is one of them.

GIS is now a multi-million dollar industry involving millions of people around the world. Thus, according to Dataquest, in 1997, total sales of GIS software exceeded $1 billion, and taking into account related software and hardware, the GIS market is approaching $10 billion. GIS is studied in schools, colleges and universities. This technology is used in almost all spheres of human activity - be it in the analysis of such global problems as overpopulation, land pollution, hunger and overproduction of agricultural products, reduction of forest land, natural disasters, or solving specific problems such as finding the best route between points, selection of the optimal location for a new office, searching for a house at its address, laying a pipeline or power line in the area, various municipal tasks such as registering land property. How is it possible to solve such different problems using one technology? To understand this, let's look at the structure, operation and examples of GIS application in sequence.

Components of GIS

A working GIS has five key components: hardware, software, data, people, and methods.

Hardware. This is the computer running the GIS. Currently, GIS works on various types computer platforms - from centralized servers to individual or networked desktop computers.

Software A GIS contains the functions and tools needed to store, analyze, and visualize geographic (spatial) information. The key components of software products are: tools for entering and manipulating geographic information; database management system (DBMS or DBMS); tools to support spatial queries, analysis and visualization (display); graphical user interface (GUI or GUI) for easy access to tools and functions.

Data. This is probably the most important component of GIS. Spatial location data (geographic data) and associated tabular data may be collected and produced by the user or purchased from vendors, commercially or otherwise. In managing spatial data, a GIS integrates spatial data with other data types and sources, and can also use the DBMSs used by many organizations to organize and maintain the data they have.

Performers. Widespread use of GIS technology is impossible without people who work with software products and develop plans for using them to solve real problems. GIS users can be both technical specialists who develop and maintain the system, and ordinary employees (end users) to whom GIS helps solve everyday matters and problems.

Methods. The success and efficiency (including economic) of using GIS largely depends on a properly drawn up plan and work rules, which are established in accordance with the specifics of the tasks and work of each organization.

How does GIS work?

A GIS stores information about the real world as a set of thematic layers that are aggregated based on geographic location. This simple but very flexible approach has proven its value in solving a variety of real-world problems: tracking the movement of vehicles and materials, detailed mapping of real-life conditions and planned activities, and modeling global atmospheric circulation.

All geographic information contains information about spatial location, whether it is a reference to geographic or other coordinates, or references to an address, postal code, electoral district or census district, land or forest identifier, road name or milepost on a highway, etc. When such links are used to automatically determine the location or locations of the feature(s), a procedure called geocoding is used. With its help, you can quickly determine and see on the map where the object or phenomenon you are interested in is located (the house where your friend lives or the organization you need is located; the place where an earthquake or flood occurred; a route along which it is easier and faster to get to the desired you point or home).

Vector and raster models. GIS can work with two significantly different types of data - vector and raster. In a vector model, information about points, lines, and polygons is encoded and stored as a set of X,Y coordinates (in modern GIS, a third spatial coordinate and a fourth, for example, a temporal coordinate are often added). The location of a point (point object), for example a borehole, is described by a pair of coordinates (X,Y). Linear features such as roads, rivers, or pipelines are stored as sets of X,Y coordinates. Polygon features such as river catchments, land parcels, or service areas are stored as a closed set of coordinates. The vector model is especially useful for describing discrete objects and is less suitable for describing continuously changing properties, such as population density or accessibility of objects. The raster model is optimal for working with continuous properties. A raster image is a set of values for individual elementary components (cells); it is like a scanned map or picture. Both models have their advantages and disadvantages. Modern GIS can work with both vector and raster data models.

Problems that GIS solves

General purpose GIS typically perform five procedures (tasks) with data, among others: input, manipulation, management, query and analysis, and visualization.

Enter. To be used in a GIS, data must be converted into a suitable digital format. The process of converting data from paper maps into computer files is called digitization. In modern GIS, this process can be automated using scanner technology, which is especially important when carrying out large projects. For a relatively small amount of work, data can be entered using a digitizer. Some GIS have built-in vectorizers that automate the process of digitizing raster images. Many data have already been translated into formats that are directly understandable by GIS packages.

Manipulation. Often, to complete a specific project, existing data must be further modified to meet the requirements of your system. For example, geographic information may be presented at different scales (street centerlines are at a scale of 1:100,000, census tract boundaries are at a scale of 1:50,000, and residential features are at a scale of 1:10,000). For joint processing and visualization, it is more convenient to present all data on a single scale and the same map projection. GIS technology provides different ways to manipulate spatial data and extract the data needed for a specific task.

Control. In small projects, geographic information may be stored as regular files. But with an increase in the volume of information and an increase in the number of users, it is more effective to use database management systems (DBMS), special computer tools for working with integrated data sets (databases) for storing, structuring and managing data. In GIS, it is most convenient to use a relational structure, in which data is stored in tabular form. In this case, common fields are used to link tables. This simple approach is quite flexible and is widely used in many GIS and non-GIS applications.

Query and analysis. If you have GIS and geographic information, you will be able to get answers to both simple questions (who is the owner of this land plot? At what distance from each other are these objects located? Where is this industrial zone located?), and to more complex ones that require additional analysis (where is place to build a new house? what is the main type of soil under the spruce forests? how will the construction of a new road affect traffic?). Questions can be asked with a simple mouse click on a specific object, as well as through advanced analytical tools. Using GIS, you can identify and set search patterns and play out scenarios like “what will happen if...”. Modern GIS have many powerful tools for analysis. Among them, the two most significant are proximity analysis and overlap analysis. To analyze the proximity of objects relative to each other, GIS uses a process called buffering. It helps answer the following types of questions: How many houses are within 100 m of this body of water? How many customers live within 1 km of this store? what is the share of oil produced from wells located within 10 km from the control building of this oil and gas production department? The overlay process involves the integration of data located in different thematic layers. In the simplest case, this is a mapping operation, but in a number of analytical operations, data from different layers is physically combined. Overlay, or spatial aggregation, allows, for example, the integration of data on soils, slope, vegetation and land tenure with land tax rates.

Visualization. For many types of spatial operations, the end result is a representation of the data in the form of a map or graph. A map is a very effective and informative way of storing, presenting and transmitting geographic (spatially referenced) information. Previously, maps were created to last for centuries. GIS provides amazing new tools that expand and advance the art and science of cartography. With its help, the visualization of the maps themselves can be easily supplemented with reporting documents, 3D images, graphs, tables, charts, photographs and other means, such as multimedia.

Related technologies

GIS is closely related to a number of other types of information systems. Its main difference lies in the ability to manipulate and analyze spatial data. Although there is no single, generally accepted classification of information systems, the following description should help distance GIS from desktop mapping, CAD, remote sensing, database management systems (DBMS), and global technology. positioning (GPS).

Desktop mapping systems use cartographic representation to organize user interaction with data. In such systems, everything is based on maps; the map is a database. Most desktop mapping systems have limited data management, spatial analysis, and customization capabilities. The corresponding packages work on desktop computers - PC, Macintosh and low-end UNIX workstations.

CAD systems capable of creating project drawings, building and infrastructure plans. To combine into a single structure, they use a set of components with fixed parameters. They are based on a small number of rules for combining components and have very limited analytical functions. Some CAD systems have been extended to support cartographic representation of data, but, as a rule, the utilities available in them do not allow efficient management and analysis of large spatial databases.

Remote sensing and GPS. Remote sensing techniques are both an art and a scientific discipline for taking measurements of the earth's surface using sensors such as various cameras on board aircraft, global positioning system receivers and other devices. These sensors collect data in the form of sets of coordinates or images (nowadays predominantly digital) and provide specialized processing, analysis and visualization capabilities for the resulting data. Due to the lack of sufficiently powerful data management and analysis tools, the corresponding systems in their pure form, that is, without additional functions, can hardly be classified as real GIS.

Database Management Systems designed for storing and managing all types of data, including geographic (spatial) data. DBMSs are optimized for such tasks, so many GIS have built-in DBMS support. These systems for the most part do not have tools for analysis and visualization similar to GIS.

What can GIS do for you?

Perhaps the main “trump card” of GIS is the most natural (for humans) presentation of both spatial information itself and any other information related to objects located in space (the so-called attribute information). The ways of presenting attribute information are different: it can be a numerical value from a sensor, a table from a database (both local and remote) about the characteristics of an object, its photograph or a real video image. Thus, GIS can help wherever spatial information and/or information about objects located in specific locations in space is used. From the point of view of their areas of application and economic effect, GIS can do the following:

Make spatial queries and perform analysis. GIS's ability to search databases and perform spatial queries has enabled many companies to earn millions of dollars. GIS helps reduce the time it takes to respond to customer requests; identify areas suitable for required activities; identify relationships between various parameters (for example, soils, climate and crop yields); identify locations of power supply breaks. Realtors use GIS to find, for example, all the houses in a certain area that have slate roofs, three rooms and 10-meter kitchens, and then to list more detailed description these buildings. The request can be clarified by introducing additional parameters, for example cost. You can get a list of all houses located at a given distance from a certain highway, forested area or place of work.
Improve integration within the organization. Many organizations using GIS have discovered that one of their main benefits lies in the new opportunities to improve the management of their organization and its resources based on the geographic integration of existing data, the ability to share and modify it in a coordinated manner across different departments. The possibility of collective use and a database that is constantly expanded and corrected by different structural divisions make it possible to increase the efficiency of both each division and the organization as a whole. Thus, a company engaged in engineering communications can clearly plan repair or preventative work, from obtaining complete information and displaying on a computer screen (or on paper copies) relevant areas, such as water mains, to automatically identifying residents who will be affected by the work and notifying them when heating or water outages are expected.
Help make more informed decisions. GIS, like other information technologies, supports the well-known adage that better information leads to better decisions. But GIS is not a tool for making decisions, but a tool that helps speed up and increase the efficiency of the procedure for making decisions. It provides answers to queries and functions for analyzing spatial data, presenting analysis results in a visual and easy-to-read form. GIS help, for example, in solving such problems as providing a variety of information at the request of planning authorities, resolving territorial conflicts, choosing optimal (from different points of view and according to different criteria) locations for placing objects, etc. The information required for decision-making can be presented in a concise cartographic form with additional text explanations, graphs and diagrams. The availability of information that is accessible to perception and generalization allows decision-makers to focus their efforts on finding a solution without spending significant time collecting and understanding the available heterogeneous data. You can quickly consider several solution options and choose the most effective and cost-effective one.
Create maps. Maps have a special place in GIS. The process of creating maps in GIS is simpler and more flexible than traditional manual or automatic mapping methods. It starts with creating a database. The digitization of ordinary paper maps can also be used as a source for obtaining initial data. GIS-based cartographic databases can be continuous (without division into separate sheets and regions) and are not related to a specific scale or map projection. Based on such databases, it is possible to create maps (in electronic form or as hard copies) of any territory, of any scale, with the required load, with its selection and display with the required symbols. At any time, the database can be updated with new data (for example, from other databases), and the data available in it can be corrected and immediately displayed on the screen as needed. In large organizations, the created topographic database can be used as a basis by other departments and divisions; At the same time, it is possible to quickly copy data and send it over local and global networks.

"CAD and graphics" 5"2000

Geographic information system is a system for collecting, storing, analyzing and graphically visualizing spatial (geographic) data and related information about the necessary objects. It is also used in a narrower sense - as a tool (software product) that allows users to search, analyze and edit both a digital map of the area and additional information about objects.

"Geographic Information System" is a set of hardware and software tools and algorithmic procedures designed for collecting, entering, storing, mathematical and cartographic modeling and figurative representation of geospatial information.

Geospatial data" means information that identifies the geographical location and properties of natural or artificially created objects, as well as their boundaries on earth. This information can be obtained through (among other means) remote sensing, mapping and various types of surveying.

Geographic data contains four integrated components: location,

Properties and characteristics, spatial relationships, time.

GIS: geography, cartography, remote sensing, topography and photogrammetry, computer science, mathematics and statistics.

2. Areas of use of GIS.

GIS includes the capabilities of database management systems (DBMS), raster and vector graphics editors and analytical tools and is used in cartography, geology, meteorology, land management, ecology, municipal government, transport, economics, defense and many other areas.

3.GIS classification.

By functionality: - full-featured general-purpose GIS;

Specialized GIS, focused on solving a specific problem in any subject area;

Information and reference systems for home and information and reference use. The functionality of GIS is also determined by the architectural principle of its construction:

According to spatial (territorial) coverage, GIS are divided into global (planetary), national, regional, local (including municipal).

By problem-thematic orientation - general geographic, environmental and environmental management, sectoral (water resources, forestry, geological, tourism, etc.).

According to the method of organizing geographic data - vector, raster, vector-raster GIS.

4. GIS structure.

Non-positional (attributive): descriptive.

Data (spatial data):

Positional (geographic): the location of an object on the earth's surface.

Hardware (PCs, networks, drives, scanners, plotters, etc.).

Software (software).

Technologies (methods, procedures, etc.).