Cartographers classify maps depending on type of information and symbols. There are seven different kind of maps :-
- Thematic map / Choropleth map
- Dot map
- Dasymetric map
- Proportional symbol map
- Charts maps
- Flow map
- Isarithmic map
Thematic map / Choropleth map
These maps display spatial information to show the location and distribution of specific phenomenon.
One of the popular type of thematic map is the choropleth map where we use color schemes to represent statistics. For example below is a map which shows age distribution of population between different areas. The dark color indicates old population as compared with lighter color indicating comparatively younger population.
A dot map uses a dot to represent the number of a phenomenon found within the boundaries of a geographic area. For instance below is a dot map which shows number of walmarts across US. There are two kinds of dot map one to one and one to many.
One to one uses unit value of one for a single dot.
In one to many dot maps one dot can represent one value of many value. For example below is simple map which shows number of walmarts in US. The smallest circle represent 1 walmart store but the biggest one presents 100.
Dasymetric map is a variation of choropleth map. The areas and boundaries of Dasymetric map depend on values rather than fixed administrative boundaries. For instance you can see how the below areas and boundaries are changing as per socioeconomic and residential areas.
These boundaries are created from the statistics rather than administrative boundaries. In Arcgis “graduated color map” is used to create Dasymetric maps.
Proportional symbol map
In this we have a specific symbol size for numeric value. For example below we have circle symbols which represent number of counties in a state. The biggest circle is 100% followed by 60.50% and so on. So here the circle symbol size represents the numeric value.
They use pie charts or bar charts to represent data. For example below is a simple chart map which shows pie chart distribution as per area.
This map displays different quantities of data such wind, weather , traffic etc using line and its thickness. For example below is a flowmap which shows immigration flow between continent in the year 2007. The more the arrow lines are thick the more the immigration flow is heavy.
It uses isolines to represent a surface. Each isoline connects points of equal value. This map is useful to display things like terrain.