Five Types of Maps

Clorpleth Map

A chloropleth map is one which a specific color or pattern is used to identify all areas with the same statistical data for a given variable.  A different color or pattern is used for an area with another set of statistical data.  Chloropleth maps are used to illustrate a variety of subject matter such as demographics or scientific data.  This one illustrates how the electoral vote was divided between Democrats and Republicans in the 2008 Presidential election.

Dot Density Map

A dot density map uses groups of dots to quantitatively represent a given phenomenon or feature.  The more dots there are in an area on the map, the more common the feature or phenomenon.  Dot density maps can be used to demonstrate the distribution of anything from people, frogs, or mosquitoes to manhole covers or yellow cabs in a designated area.  This one shows the distribution of American farms in 1997.

 

Proportional Symbol Map

A proportional symbol map illustrates the variation in distribution of a feature or phenomenon by using a given symbol and simply varying its size proportionally.  These maps may be used in similar ways to chlorpleth and dot density maps.  The map above identifies the number of internet users in each European country in 2004.  Note where the data came from:  the American CIA.  Big brother is watching!

 

Isopleth Map

Isopleth maps, sometimes called contour line maps, depict data that has been collected over an area.  The contour lines connect points where identical statistical data has been collected.  In the example above, data has been compiled over many years.  The lines connect weather data collection stations that demonstrate t the same average rainfall over that period.  Other types of isopleths include topographic maps which show elevation of above sea level for Earth’s terrestrial areas and bathymetric maps which show depth below sea level in aquatic environs.

 

Environmental Sensitivity Map

Environmental Sensitivity Index (ESI) maps identify wildlife, their habitat, and other resources that are vulnerable to the impact of human activity and natural disaster.  The purpose of these maps is to aid planners in setting priorities when preparing strategies to respond to events that threaten an environmentally sensitive area. ESI maps provide planners with information about land type and structure, biological habitation, and human-use resources.  This is cloropleth ESI map of Slovenia identifies areas of vulnerability by indexing each area according to its environmental sensitivity.

 

An Amazing Weather Event

Click Here for astounding video of a real Texas-sized hail storm.