Income maps are a very common type of thematic map. They show variations of income across a geographic area. The standard mapped variable for an income map is median household income. Income tends to be highly geographic because rural portions of a state or country often have lower median household income than urban areas. Within urban areas, income can also be highly variable because neighborhoods tend to be populated by people with similar income levels.
Concentrate all your thoughts upon the work in hand. The sun's rays do not burn until brought to a focus.
When we strive to become better than we are, everything around us becomes better too.