**2.1 GIS**

A GIS is a system capable of entering, storing, modifying, recording, query, reorganizing, analysis, and display as well as presenting alphanumerically and graphically data located in space to solve a problem, support a decision, and help to plan. It comprises of functional modules allowing to create and modify, to interrogate and to represent cartographically data located in space. There are several components when working on a GIS Project. These consists of setting up a GIS unit, the design, development and information of a reliable database, the implementation of a knowhow for the launch of a dynamic GIS, the use of simple GIS software to fill in the heritage database, acquisition of a suitable hardware platform. Also, there are several basic questions that a GIS should be able to answer such as:


There are two fundamentally different types of GIS data used in GIS projects:

• **Vector data:** Which are structured data used to store spatial data like lines, points, and polygons. They are based on vectors as opposed to space occupancy raster structures.

• **Raster Data:** A map in a raster data divides the entire study area into a regular grid of cells in a specific sequence. The data completely fill the space of the map.

The power of a GIS comes from the ability to relate different information in a spatial context and to reach a conclusion about this relationship. Most of the information on the world contains a location reference, placing that information at some point on the globe. A GIS, therefore, can reveal important new information that leads to better decision making.
