Equidistant projection
Also called: True-scale projection · Topic: Map Projections · NCERT: Class 11, Ch 4 "Map Projections"
Meaning
An equidistant projection, also called a true-scale projection, keeps distance correct. But it does this only along certain chosen parallels or meridians. No flat map can keep the scale true everywhere, because a sphere cannot be flattened without stretching. So "equidistant" always means "true along some lines only", never across the whole map.
Example
The simple (equidistant) cylindrical projection keeps true scale along all meridians and along the equator. So on such a map, the north-south distance from Kanniyakumari to Leh can be measured correctly along a meridian. East-west distances away from the equator are stretched.
Don't confuse with
- Azimuthal equidistant projection: this is one kind of equidistant projection. It shows true distance along every line from one centre point, for example from Delhi to any capital.