What is GIS ?

 

A Geographic Information System (GIS) is, as its name implies, an information system dedicated to the creation, management, analysis, visualisation and diffusion of spatial (or geo-referenced) or attribute data. A GIS makes it possible to represent and analyse all elements and phenomena present on earth. 

The visualisation of the data can be in the form of 2D maps, 3D models or in the form of relations or graphs, which may be either static or dynamic.

This different representation of data makes it simpler to read and interpret so as to facilitate spatial analyses and improve understanding of the elements and phenomena that surround us, since the spatial aspect adds to any analysis a considerable advantage because it can show links between elements or phenomena, which would be hard to see without displaying the data on a map.

Furthermore, the world of GISs is not limited to spatial analysis, since other integral parts include following vehicles in real time, geolocalisation, calculating itineraries and modelling networks (roads, railways, energy suppliers, etc).

Furthermore, GIS is no longer competing with IT.  It is now an integral part of it! 

The components of a GIS

Softwares

GIS software can store, analyse and visualise all kinds of spatial information. GIS software is composed of tools which stock geographical information digitally, a management system for databases and tools to manipulate, interrogate and visualise geographical information.

 

 

Data

The data of a GIS can be spatial or attribute.  Spatial (or georeferenced) data is all the data localised on the earth's surface using geographical coordinates. These data may be bases of addresses, vector data (points, lines, polygons) or matrix data (rasters, satellite images, aerial photography etc). Attribute data is qualitative. It enables description of the objects represented on a map. 

Devices

Now that the use of GISs has been extended to an increasing number of users, most GIS applications are available on servers, standard computers, tablets and smartphones.

 

Methods and procedures

Certain methods and procedures must be followed in order to implement an efficient GIS.

Users

More and more people are using GISs and they are now available to everyone. Some people use them professionally but many others use them in daily life by visualising maps on the internet, using their GPS etc.