You know that geospatial maps are comprised of thematic layers, that these data must be in an earth-based reference system, and that overlaying them can illuminate complex patterns and relationships. Another crucial and powerful aspect of geospatial data are attributes, or non-spatial information associated with a spatial feature.

A feature in a GIS is linked to its record in the attribute table through a unique numerical identifier (ID). Every feature in a map layer has an identifier and any other attribute information provided by the data’s author(s). Because features on the map are linked to their records in the table, you can view and analyze that information in GIS.

Visit the Vassar Community Map Gallery and click the COVID-19 Community Resources Web Map, created by Vassar-based Hudson Valley Mappers. This map shows locations of community resources and businesses in Dutchess County, including health services (Coronavirus testing facilities, hospitals, medical clinics, pharmacies), food services (food pantries, meal programs, school meal distribution sites, grocery stores, restaurants, farm markets), and free wifi locations. Clicking on a feature calls up its attribute information from a database table that sits behind the data, and displays it in the pop-up window.

Community Resources in Dutchess County (COVID-19)
The information displayed in the pop-up window of a feature in the Community Resources in Dutchess County (COVID-19) map (above)is pulled from the feature’s record in a database table (below).

>> 7) Vector and Raster Data