What is Geographic Information Systems (GIS) -What is The Scope of GIS In Pakistan

What is Geographic information systems

Geographic information systems (GIS) are automated systems, the functions of which are collection, storage, integration, analysis and graphical interpretation of spatio-temporal data, as well as related attributive information about objects represented in GIS.

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

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

Stages of GIS creation:

pre-design studies, including the study of user requirements and the functionality of the software used,
feasibility study (FS)
profitability assessment,
system design of GIS, including the stage of the pilot project, development of GIS;
testing GIS on a small territorial fragment or test site or creating a prototype,
introduction of GIS;
operation and maintenance of GIS.

Sources of data for creating GIS:

the base layer - cartographic materials (topographic and general geographic maps, maps of administrative-territorial division, 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 the created base maps, on the basis of which construction of digital models in GIS and practically all their tasks are realized.
remote sensing data (ERS): including materials received from spacecraft and satellites, Images are received and transmitted to Earth from carriers of imaging equipment located in different orbits. The obtained images differ in a different level of visibility and detail of displaying objects of the natural environment in several ranges of the spectrum (visible and near infrared, thermal infrared and radio ranges), which allows solving 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 relief. The materials of such surveys provide both quantitative and qualitative information about various objects of the natural environment;
Eesults of geodetic measurements on the ground, performed by levels, theodolites, electronic tacheometers, GPS receivers, etc.
data from state statistical services for various sectors of the national economy, as well as data from stationary measuring stations of observations (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 geographic objects). In GIS, only one type of data is rarely used, most often it is a combination of various data on any territory.

The effective use of GIS for solving various 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 of obtaining various information from a map, mathematical and other methods of using this information to solve spatially -localized GIS tasks.

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

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

Geodata - data about objects, forms of territory and infrastructures on the surface of the Earth, and as an essential element, they must have spatial relationships.

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

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

aerial photography, which includes aerial photography, photography from mini-media;
global positioning system (GPS);
satellite imagery, which is one of the most important data sources for GIS in conducting natural resource research, environmental monitoring, assessment of agricultural and forest lands, etc .;
maps or cartographic information, which is the basis for building digital GIS models;
data received via the worldwide Internet;
the 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 survey is based on the use of digital photogrammetric cameras, which allow displaying information in digital form directly to a computer;
video filming, as a data source for GIS, is used mainly for monitoring purposes;
Documents, including archival tables and catalogs of coordinates, serve as the main source of data for entering into GIS so-called subject or thematic information, which includes economic, statistical, sociological and other types of data;
Geodetic methods (automated and non-automated) are used to refine coordinate data,
the data source for GIS is also the results of processing in other GIS;
photographs, pictures, drawings, diagrams, video images and sounds;
statistical tables and text descriptions, technical data;
postal addresses, phone books and directories;
geodetic, ecological 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 operational measures in emergency situations, etc.

GIS are classified according to the following criteria:

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