By: GIS Geography · Last Updated: March 12, 2020
Equal Area Projection Maps Advantages and Examples
The equal area projection retains the relative size of area throughout a map.
So that means at any given region in a map, an equal area projection keeps the true size of features.
While equal area projections preserve area, it distorts shape, angles and cannot be conformal.
Let’s review some advantages and examples of using equal-area projection maps.
Examples of Equal-Area Projection Maps
As shown in the examples below, equal area projection maps preserves the size of features true to their real area.
For example, keep an eye on how Greenland retains its true size of area throughout each map.
But if you look at a Mercator projection map below, Greenland becomes abnormally large due to its distortion in area at the poles.
And Antarctica looks like it’s bigger than all the other continents.
USGS Uses the Albers Equal Area Conic Projection
The USGS commonly uses the Albers Equal Area Conic projection because of how it proportionally represents areas for the conterminous United States.
H. C. Albers first introduced this map projection in 1805 with two standard parallels (secant). Since then, cartographers have used it for displaying large countries that require equal-area representation
Like all map projections, the Albers Equal Area Conic Projection distorts other properties in a map. For example, distances and scale are true only on both standard parallels.
Although direction is reasonably accurate, it’s not conformal, perspective, or equidistant.
Tissot Circles and Distortion
In an equal area projection, Tissot circles are all the same relative size across the map.
Despite how the indicatrices change from a circle to an ellipse, an equal-area projection retains relative size.
So now you have an idea how equal area projections work, we have a section entirely dedicated to the types of distortions found in maps.
Also, we’ve explained about developable surfaces like cones, cylinders and planes and how they flatten a 3D globe into a two-dimensional map.
What are some of your favorite types of equal area projections? Please let us know with a comment below.