Modern
information technologies / 3. Software
Ivanova B.V. Ph.D.
Kostanay State University of A. Baitursynov, Kostanay
Methods and technologies of modeling in GIS
Modern geo information
systems (GIS) represent new type of the integrated information systems which,
on the one hand, include methods of data processing of the automated systems
(AS) much earlier, with another – possess specifics in the organization and
data processing. Practically it decided GIS as multi-purpose, multidimensional
systems.
On the basis
of the analysis of the purposes and problems of various GIS, the modeling now,
more exact should consider GIS definition as geo information systems, instead
of as geographical information systems. It is caused also by that the percent
of purely geographical data in such systems is insignificant, technologies of
processing, and have a little the general with traditional processing of
geographical data and, at last, geographical data form only base of the
solution of a large number of the applied tasks which purposes are far from
geography.
In GIS it is
possible to allocate four main groups of modeling:
1. Semantic
– at the level of collection of information;
2. Invariant
– a basis of submission of maps, due to use of special libraries, for example libraries
of conventional signs and libraries of graphic elements;
3. Heuristic
– communication of the user with the computer on the basis of the scenario
considering technological features of the software and feature of processing of
this category of objects (takes a leading place at interactive processing and
in control and correction processes);
4.
Information - creation and transformation of different forms of information to
the look which is set by the user (is the basic in subsystems of documentary
providing).
When
modeling in GIS it is possible to allocate the following program and
technological blocks:
Operations
of transformation of formats and data presentation. Are important for GIS as a
means of exchanging data with other systems. Transformation of formats is
carried out by means of special programs converters (AutoVEC, WinGIS,
ArcPress).
Projective
transformations. Carry out transition from one cartographical projection to
another or from spatial system to a cartographical projection. As a rule, foreign
software don't support directly projections widespread in our country, and
information on type of a projection and its parameters to receive quite
difficult. It defines advantage of domestic development of GIS containing sets
of the necessary projective transformations.
Geometrical
analysis. For the GIS vector models it is operations of determination of
distances, lengths of broken lines, search of points of intersection of lines;
for the raster – operations of identification of zones, calculation of the
areas and perimeter of zones.
Overlay
operations: imposing of modeling layers with generation of derivative objects
and inheritance of their attributes.
Functional
modeling operations:
-
calculation and creation of buffer zones (are applied in transport systems,
forestry, at creation of security zones round lakes, when determining zones of
pollution along roads);
- the
analysis of networks (allow to solve optimizing problems on networks – search
of ways, division into districts);
-
generalization (are intended for selection and display of cartographical
objects according to the scale, the contents and a thematic orientation);
- digital
modeling of a relief (consists in creation of model of the database which is
best displaying a relief of the studied district).
The complex
system of information security has to be under construction taking into account
four levels of any information system (IS), including and geo information
system:
- Level of
the applied software (S) which is responsible for interaction with user.
Example of the IS elements working at this level, it is possible to call a text
editor of WinWord, the editor of spreadsheets of Excel, the post Outlook
program, Internet Explorer browser, etc.
- Level of
the database management system (DMS) which is responsible for storage and data
processing of information system. Example of the IS elements working at this
level, it is possible to call DBMS Oracle, MS SQL Server, Sybase and even MS
Access.
- Level of
the operating system (OS) which is responsible for service of DBMS and the
applied software. Example of the IS
elements working at this level, it is possible to call OS Microsoft Windows NT,
Sun Solaris, Novell Netware.
- Level of a
network which is responsible for interaction of knots of information system.
Example of the IS elements working at this level, it is possible to call the
TCP/IP, IPS/SPX and SMB/NetBIOS protocols.
Set of
application of various means of protection at all GIS levels will allow to
construct effective and reliable system of ensuring information security of geo
information system. Such system will guard interests and users, and the staff
of the company provider of GIS-services. She will allow to lower, and in many
cases and completely to prevent, possible damage from attacks to components and
resources of system of processing of cartographical information.
References:
[1]. Koltsov AS Geographic Information Systems: Proc.
Benefit / AS Koltsov, ED Fedorkov. Voronezh: VPO
"Voronezh State Technical University", 2006.