EESC 3750 - Geographic Information Systems: Types of Geospatial Data

When working with geospatial data in a GIS, you need to understand the types of data you are using. The types of data will determine how to visualize and the types of analyzes that you can do. First, there are spatial and non-spatial data. Spatial, as the name implies, has a location associated with it.

There are two types of spatial data: discrete  and continuous. In general, discrete data are commonly represented in a vector data model, while continuous data are represented in a raster data model.

Non-spatial data, often called attribute data, are the characteristics associated with the spatial data. These attributes can take one of the forms:

• Nominal data: a unique identifier, like a SSN.
• Ordinal data: a kind of data that refers to a ranked order. Ordinal data represents the rankings themselves, not the numbers associated with the rank
• Interval data: a type of numerical data in which the difference between the numbers is significant but there is no non-arbitrary zero point associated with the data
• ratio data: a type of numerical data in which the differences between the numbers is significant, but there is a fixed non-arbitrary zero point associated with the data.