-Introduction in GIS:

 

•A GIS is a computer system capable of assembling, storing, manipulating, analyzing and displaying geographically referenced information, i.e. data identified according to their locations.

 

•A GIS also includes operating personnel and the data that go into the system.

 

 

 

 

 

 

 

 

 

 

 

 - The components of GIS: 

GIS integrates five key components:

 

• Hardware like computers, network (GoogleEarth), quantizers (video, digitizer,GPS,scanner) , output devices(printers).

• Software is a tools for input and manipulation of geographic information. 

• Data is an important component of GIS. 

 

 

 

 

 

• People: GIS technology is of limited value without the people who manage the system and develop plans for applying it to real world problems.

 

 

 

 

 

 

 

 

 

 

 

 - Geographic data:

 

• Spatial data: referenced to geographic space like coordinate system (grid), projection, source (land survey, GPS, aerial imagery). Also, the spatial data represented at geographic scale.

 

- The most common questions in GIS:

• Is a GIS a map?

- No, but maps can be made using a GIS. A map is a static spatial representation, but a GIS provides dynamic spatial representations. Maps are a good starting point: Reference maps Location; Thematic maps Geographic distributions Maps are essentially outdated the moment they are printed. Changes across the globe are occurring constantly. GIS allows for easy and continuous updating.

 

• What are the functions of GIS?

- data acquisition and pre-processing.

- data based management and retrieval.

- spatial measurement and analysis.

- graphic output and visualization.