Geospatial Data: What is Geospatial Data?

GIS stands for Geographic Information System.  A GIS is a computer system for capturing, storing, querying, analyzing, and displaying geographic data. GIS has many, wide-ranging applications.  It can be used for cartography, resource management, urban planning, marketing, statistical analysis, environmental impact assessment, and for countless other areas.

Geospatial data (GIS data or geodata) has explicit geographic positioning information included within it, such as a road network from a GIS, or a geo-referenced satellite image. Geospatial data may include attribute data that describes the features found in the dataset.

There are two types of geospatial data - vector and raster.

Vector data uses the simple geometric objects of points, lines, and areas (polygons) to represent spatial features.

Raster data uses a grid to represent its geographic information.  Points are represented by single cells, lines by sequences of neighboring cells, and areas by collection of grouping cells.

Other types of raster data include:

• Satellite Imagery - remotely sensed satellite data

• Digital Elevation Models- an array of uniformly spaced elevation data

• Digital Orthophotos - digitized image prepared from an aerial photograph or other remotely sensed data, in which the displacement or distoration have been removed

• Graphic Files - scanned maps, photographs, and images in TIFF, GIF, or JPEG format