What Are Projection Areas?

Map projection is a theory and method that uses certain mathematical rules to transform the longitude and latitude lines on the earth's surface to a plane.

Map projection

Map, Map Projection. The theory and method of transforming any point on the surface of the earth to a map plane by using certain mathematical rules.

Due to the deformation of the projection, the geometric characteristics (length, area, angle, shape) of the features represented on the map, such as continents, islands, and oceans, are also deformed. Each map is deformed to different degrees; on the same map, the deformation is different in different regions. The larger the range shown on the map, the farther away from the projection standard

Since the earth is an irregular pear-shaped sphere with a slightly wider equator and slightly flat poles, its surface is an unflattened surface. Therefore, any mathematical method for this conversion will produce errors and deformations. Errors have produced various projection methods. According to the nature of the deformation, map projections can be divided into four categories:

The earliest mapping using projection was the 3rd century BC

1. According to the deformation method

(1) Isometric projection, also known as

Common projection methods are

Orthogonal Cone Cone Equal Area Projection (

The location, shape, and extent of the area being plotted, the scale, content, and publishing method of the map affect the type of projection. For example, in the polar region, it should be a positive azimuth projection, and in the middle latitudes, a positive cone projection is used.

Topographic maps are usually made using Gauss-Kruger projections. Area maps are usually made using azimuth projections, conic projections, and pseudo-conic projections. World maps are usually made using polyconic, cylindrical, and pseudo-cylindrical projections. But in general, it depends on the actual situation.