GIS Spatial Data Model

GIS Spatial Data Model

Traditionally spatial data has been stored and presented in the form of a map. Three basic types of spatial data models have evolved for storing geographic data digitally. These are referred to as:

ü     Vector Data Model

ü     Raster Data Model               

•  Vector Data

ü      Map features

o       Points, lines, polygons

o       Feature attributes

ü      Every feature has attributes

o       (e.g. name, area, population)

• Raster Data

• Stored electronic image or picture taken as an aerial photograph or satellite image.
• Composed of a rectangular array of square cells, called pixels, with a number in each cell representing the solid color fill of that cell.
• A new hybrid method of storing data is that of identifying point clouds, which combine three-dimensional points with RGB information at each point, returning a "3D color image".
• GIS thematic maps then are becoming more and more realistically visually descriptive of what they set out to show or determine.