Raster

Raster Data Types:

The basic units of spatial information are represented as rasters (grids). Raster data structures do not provide specific provisions to represent the following:

• Point = 1 cell
• Line = Multiple cells joined at edges or corners, usually with only 1 or 2 neighbors
• Polygon = Group of contiguous cells joined at edges or corners

Advantages of Raster Structure:

• Overlaying maps is easy and "perfect" (i.e. no possibility of sliver polygons developing since all raster cell borders are coincident).
• Integration of remotely sensed imagery (satellite images or scanned airphotos) is staight-foreward.
• A huge variety of complex spatial analysis are supported.
• Software is generally cheaper and easier to learn compared to vector GISs.

Overlay Stored in Raster Format: