Geoinformation technologies - Information technology

Geoinformation technologies

Currently, in accordance with the requirements of new information technologies, many control systems are created and are functioning related to the need to display information on an electronic map:

• Geoinformation systems;

• federal and municipal government systems;

• Design systems;

• military systems, etc.

These control systems regulate the operation of technical and social systems operating in a certain operational space (geographic, economic, etc.) with a clearly expressed spatial nature.

When solving problems of social and technical regulation in management systems, a lot of spatial information is used: topography, hydrography, infrastructure, communications, location of objects.

Graphical representation of any situation on the computer screen implies displaying various graphic images. The graphic image generated on the computer screen consists of two parts that are different from the point of view of the storage environment - graphic "substrate" or graphic background and other graphic objects. In relation to these other graphical images, the "image-substrate" is an area & quot ;, or a spatial two-dimensional image. The main problem in the implementation of geoinformation applications is the difficulty of a formalized description of a particular domain and its display on an electronic map.

Thus, geoinformation technologies are designed to widely introduce into practice methods and tools for working with spatiotemporal data represented as an electronic chart system and subject-oriented media for processing heterogeneous information for different categories of users.

The main class of data of geoinformation systems (GIS) is the coordinate data containing geometric information and reflecting the spatial aspect. Basic types of coordinate data: point (nodes, vertices), line (not closed), contour (closed line), polygon (area, area). In practice, more data is used to construct real objects (for example, a hanging node, a pseudo node, a normal node, a cover, a layer, etc.). In Fig. 5.1 shows the main of the considered elements of the coordinate data [29].

The types of data considered have a greater number of different connections, which can be conditionally divided into three groups:

• relationships for constructing complex objects from simple elements;

• Relationships calculated by the coordinates of objects;

• Interrelationships defined using a special description and semantics when entering data.

The basis for visual representation of data using GIS-technologies is a graphical environment, based on vector and raster (cellular) models.

Basic elements of coordinate (a) and vector (b) data

Fig. 5.1. Basic coordinate elements ( a ) and vector (b) Data

Square Mosaic

Fig. 5.2. Mosaic square

Vector models are based on the representation of geometric information using vectors that occupy part of the space, which requires a smaller amount of memory. Vector models are used in transport, utility, marketing applications GIS.

In raster models, the object (territory) is mapped into spatial cells that form a regular network. Each cell of the raster model corresponds to the same surface area, which is the same in size but different in characteristics (color, density). The cell of the model is characterized by a single value, which is the average characteristic of the surface area. This procedure is called pixelization. Raster models are divided into regular, irregular and nested (recursive or hierarchical) mosaics. Flat regular mosaics are of three types: a square (Figure 5.2), a triangle (Figure 5.3), and a hexagon.

The square shape is convenient when processing large amounts of information, triangular - to create spherical surfaces. As an irregular mosaic, Triangulated Irregular Network (TIN) and Thyssen polygons (Figure 5.4) are used. They are convenient for creating digital models of landmarks for a given set of points.

Thus, the vector model contains information about the location of the object, and a bitmap about what is located in a particular point of the object. Vector models are binary or quasi-binary. Bitmaps allow you to display halftones.

Mosaic - Triangle

Fig. 5.3. Mosaic - Triangle

Thyssen Landfills

Fig. 5.4. Thyssen Landfills

The main area of ​​use of raster models is the processing of aerospace images.

A digital map can be organized in the form of multiple layers (coverings or maps of substrates). Layers in GIS represent a set of digital cartographic models built on the basis of the unification (typing) of spatial objects with common functional features. The combination of layers forms an integrated basis for the graphical part of the GIS. An example of an integrated GIS layer is shown in Fig. 5.5.

An important point in the design of GPS is the dimensionality of the model. Two-dimensional models of coordinates (2D) and three-dimensional (3D) are applied. Two-dimensional models are used when constructing -

Fig. 5.5. Example of layers of integrated GIS

maps, and three-dimensional - in the modeling of geological processes, the design of engineering structures (dams, reservoirs, quarries, etc.), modeling flows of gases and liquids. There are two types of three-dimensional models: pseudo-three-dimensional, when the third coordinate and true three-dimensional are fixed.

The majority of modern GIS carries out complex information processing:

• Primary data collection;

• accumulation and storage of information;

• Various types of modeling (semantic, imitative, geometric, heuristic);

• computer-aided design;

• Documentation.

Main areas of GIS use:

• electronic maps;

• Urban economy;

• State land cadastre;

• Ecology;

• remote sensing;

• Economy;

• Special military systems.

In Table. 5.1 gives a brief description of modern domestic and foreign GIS [50].

Table 5.1

No. п/п

Name of GIS, company-developer

Assignment

Advantages

1

ER Mapper (ER Mapping)

Processing large volumes of photogrammetric information, thematic mapping (geophysics, natural resources, forestry)

Accuracy, map printing, 3D visualization, algorithm library

2

GeoDraf, Geograf (Russia)

Construction of a cartographic structure with multilayered mapping of data, creation of electronic atlases (urban economy)

A large number of applications, the ability to use Borland C ++, Visual Basic, Delphi

3

AiOIS, Moscow State Geodesy and Cartography (Russia)

Building digital terrain models using aerospace imagery

Using a small amount of computing resources, a library of conditional signs

4

ArcCAD, ESRI - Environmental Systems Research Institute

Linking maps and databases, spatial analysis (engineering and business applications, transportation, civil engineering)

Using the language of high intelligence AutoLISP, the availability of all standard GIS technologies, the ability to process data in AutoCAD and ArcInfo

5

Arc View, ESRI

Creation, analysis, output of cartographic data (business, science, education, management, sociology, demography, ecology, transport, urban economy)

Support for relational DBMS, advanced business graphics (view form, tabular form, chart form, layout creation), creation of professionally designed cartographic information, development of own applications, interaction with other applications

6

AtlasGIS, Strategic Mapping INC (USA)

A fully functional information mapping system for analysis and presentation

Easy and flexible software, desktop option

7

SICAD/open, Siemens Nixdorf (Germany)

Processing of geoinformation data on distributed technology

System product for workstations, working with standard INFORMIX and ORACLE DBMS

8

Star, Star Informatic

Integrated modular environment, design, analysis and assessment of networks (sewage, water, energy, heat, communications, roads)

The presence of thematic oriented modules, applications for managing data models and building digital models

9

Small World GIS, Small Worid Systems Ltd, (UK)

Geographic Operating System for Modeling Space-Linked Objects

Full multiplatformity (HP, IBM, SUN, DEC)

10

CADdy,

ZIEGLER

Informatics

GmbH

Creation of cadastral and geoinformation systems (topographic survey, creation of electronic topographic maps, maintenance of a bank of topographical and geographic data, representation and visualization of various three-dimensional objects, urban economy, industry)

Using object-oriented technology, developed modular structure, development of user applications using C

11

MGE,

Integraf MGE

Application of CAD technologies for GIS tasks, support of GIS workflow and cartography in any industry

Choose the operating environment (MS Windows, Windows NT, DOS, UNIX), a modular structure, a large set of analysis and query tools (simultaneous opening of eight kinds of one object model), interactive user interface

12

MapInfo

Search of geographical objects, work with databases, processing of geodetic measurements, computer design and preparation for publication of cartographic documents

Selecting the operating environment (MS Windows, Windows NT, DOS, UNIX), universality, desktop version

13

ArcInfo

Creation of geoinformation systems, creation and management of land, forest, geological and other cadastres, design of transport networks, estimation of natural resources

Network and independent use cases (for IBM PC with limitations), easy operation, a set of drivers for selecting monitors, digitizers, plotters

14

Panorama

(Russia)

Construction and processing of digital and electronic maps, maintenance of cartographic and attributive databases

Availability of a special interface for searching for electronic map objects based on database characteristics, using simple tools for implementation

15

ERDAS

Imagine,

ERDAS

Aerospace Imaging

Modular system, graphical interface, hypertext system, ease of learning, availability for various platforms

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