Selected Data About Geographic Locations

Geographic Information Systems, or GIS, use two main types of data: spatial and attribute data.
Spatial data defines the physical location of features like roads and buildings using coordinates such as latitude and longitude.
Attribute data adds descriptive information, such as population numbers or road names, to these locations.
For example, a road’s spatial data would include its start and end coordinates, and its attribute data could indicate its name, type, highway or residential, and condition.
There are two primary models to represent spatial data: raster and vector models.
The raster model divides an area into a grid of cells, each representing a specific feature, such as a road or building.
In contrast, the vector model defines geographic features using points, lines, and polygons. Points represent locations, lines define linear features like highways, and polygons depict areas such as farms or parks.
GIS integrates these data types to create thematic maps highlighting key features like roads, boundaries, and land use, which are critical for planning and management.