GIS can be defined as tools for consulting, analyzing and editing
data, maps and spacial information in general. They are computer
systems (hardware and software) used for analysis, consulting,
developing, manipulating, storing, or in short, for handling geo-
graphic information. Therefore, GIS are systems that work with
geographic information databases.
On a digital map, we have a database associated with it, in
which we can obtain the geographic coordinates of each point.
This means that it is possible to search in both directions,
obtaining information on the map or performing the search
directly from the database.
There are two types of GIS representation, by raster data or by
vector data. Raster models are represented by a mesh or grid of
rectangles, all with the same size. Each element is called a pixel or
cell and has its information and geographic location assigned to it.
In a vector model, the geographic features in GIS are expressed
as vectors, maintaining the geometric features of the figures.
They are used to define boundaries and therefore spatial geome-
tries. The vector elements have associated information in the
database. The vector geometric elements used are: dots, lines
and polygons.
It is also clear that GIS present some difficulties to become
the general tool for solving all types of spatial problems.