These maps, where each spatial unit

These maps, where each spatial unit is filled with a uniform color or pattern, are appropriate for data that have been scaled or normalized in some way. For example, density information, expressed as "per unit area," is appropriately represented using a choropleth map. Tax rates, expressed as "per cent," are also a form of ratio data, which is most easily and correctly visualized using choropleth maps. Choropleth maps are also appropriate for indicating differences in kind of an area data, like ownership or use of land or type of forest cover.