Despite its navigational origin, map is a subcategory of visualization.
Map stands out as a distinctive approach to visualization, as geospatial data is mostly 2-dimensional and sometimes 3-dimensional. To add attributes to maps, point size, line width, shades and color are used instead of length or height. Different attributes can be overlayed for spatial correlation and pattern seeking.
Components of geospatial data:
Visual elements of a map:
Table: Map Categories by Purpose
|points||scatterplot (business location)||bubble plot (adolescent fertility rate)|
|lines||(roads, mains, sewer, cables)||lines w varying width/color (traffic speed)|
|area||categorical map (land-use zoning)||choropleth (population density)|
Thematic maps are maps designed to show a particular aspect (theme) of a geographic area.
Major thematic mapping techniques:
Advanced extensions of maps may present quantities more accurately, and incorporate the time scale: