Contents
Does projection preserve length?
Distance — Most projections distort distances (e.g., Equirectangular projection) But on an Equirectangular projection, both of those trips looks like they’re the same length, because this is a projection that does not preserve distance.
What map projections distort distance?
There are four main types of distortion that come from map projections: distance, direction, shape and area. The Mercator projection, for example, distorts Greenland because of its high latitude, in the sense that its shape and size are not the same as those on a globe. Another example is in cylindrical projections.
Can a area preserving projection be a conformal projection?
Vice versa, an area-preserving projection can not be conformal, resulting in shapes and bearings distorted in most places of the map. Each projection preserves, compromises, or approximates basic metric properties in different ways. The purpose of the map determines which projection should form the base for the map.
How are equidistant projections used in cartography?
Equidistant projections are often useful as they maintain distance relationships. However, they do not maintain distance at all points across the map. Instead, an equidistant projection displays the true distance from one or two points on the map (dependent on the projection) to any other point on the map or along specific lines.
Why is it important to use equivalent projection?
The projection you choose will depend on the characteristics most important to be preserved, given the purpose of your map. Equivalent projections preserve areal relationships. This means that comparisons between sizes of land-masses (e.g., North America vs. Australia) can be properly made on equal area maps.
What should I consider when choosing a projection?
When you choose a projection, the first thing to consider is the purpose of your map. For general reference and atlas maps, you usually want to balance shape and area distortion. If your map has a specific purpose, you may need to preserve a certain spatial property—most commonly shape or area—to achieve that purpose.