Equal area projection
Also called: Homolographic projection · Topic: Map Projections · NCERT: Class 11, Ch 4 "Map Projections"
Meaning
An equal area projection, also called a homolographic projection, keeps area correct. Every part of the map covers the same area as the matching part of the globe, at the map's scale. To keep area true, the map has to stretch land one way and squash it the other way. So shapes get distorted, especially far from the centre or near the poles. These maps are used when we need to compare sizes, as on maps of population, crops and forests.
Example
On an equal area world map, India's area can be compared fairly with Greenland's or Africa's. On a Mercator map that comparison would be wrong. Atlases use Goode's homolosine, which is an equal area projection, for world distribution maps.
Don't confuse with
- Orthomorphic projection: this keeps the shape of small areas, not their area. One map cannot be both equal area and orthomorphic.
- Orthographic projection: this is named after where the light source sits (at infinity). It looks like the globe seen from space. It is not equal area. The similar spelling is a common trap.