Understanding categorical maps
Features, layers and visual encoding
A categorical map assigns distinct colours to discrete values such as brand, store type or status. Colour identifies membership; it does not imply that one category is larger or better than another.
Consistent spelling and capitalization matter because unexpected variants can create separate categories or a fallback group.
How to read the map
Read the legend before comparing locations and inspect values grouped into the fallback colour. This tool displays the first twelve categories distinctly.
Use a graduated symbol map instead when the chosen property is numeric and magnitude is the important comparison.