Oblique projection
Topic: Map Projections · NCERT: Class 11, Ch 4 "Map Projections"
Meaning
An oblique projection is one in which the developable surface touches the globe at a point or line between the equator and a pole. This lets a mapmaker centre the map on a chosen place that is neither at the equator nor at a pole. The area around that touching point has the least distortion. It is useful when one city or region must be shown at the heart of the map.
Example
An azimuthal equidistant map with the flat plane touching the globe at Delhi (about 28°N) is an oblique projection. True distance and true direction from Delhi can be read straight off it, for example to any world capital. This makes it useful for planning air routes and radio links.
Don't confuse with
- Normal projection: the surface touches the globe at the equator.
- Polar projection: the surface touches the globe at a pole.
Related concepts
- Developable surface
- Non-developable surface
- Cylindrical projection
- Conical projection
- Zenithal projection
- Normal projection
- Polar projection