- Data modeling:

 

It  is a method to represent the real world objects in a computer. There are two common methods are used: Vector data model and Raster data model.

 

 

1- Vector data model:  is a representation of the world using points, lines, and polygons and it good for representing discrete boundaries, such as country borders and streets. 

 

2- Raster data model:  is a representation of the world as a regular grid of cells and it good for representing continuously changing attribute, as in an aerial photograph, a satellite image,  or an elevation surface.