What  is GIS

Geographic Information systems are computer aided systems that  facilitate the following tasks .

1.  capture, 
2.  modeling, 
3.  storage,
4.  retrieval,
5.  sharing,
6.  manipulation 
7.  presentation of Geographic information

GIS represents information & data about geographic objects like mountains, rivers, lakes, and not only natures creations , but human creations like buildings , houses, roads ...etc.and GIS enables  multiple information to be shown in the same format, as an example  in a Geo map you can find population layers, buildings, roads, vegetation on the same map but as different layers. 

Geo Objects 

 

Geo objects have 

• geometric data   - data about the structure of the object
• attribute date     - information that describe the object , ex : color of the surface 

different between GIS and IS is that GIS helps to solve geography related problems using Informations Systems , problems like 

ex: Directions from NY to Boston Massachusetts ,finding a elevation of a land, or else finding a certain population distribution in an area, ...etc

Some examples of GIS systems 

National Atlas of USA  - http://nationalatlas.gov/

Google earth -http://www.google.com/earth/index.html