Equirectangular projection, also known as the equidistant cylindrical projection or geographic projection, is a map projection that represents the entire globe as a rectangle. This projection is created by projecting the globe onto a cylinder, which is then unwrapped into a flat plane.
The projection is called "equirectangular" because the horizontal and vertical scales are identical, resulting in a rectangular grid of latitude and longitude lines that are equally spaced. This means that each degree of latitude and longitude is represented by the same amount of space on the map.
Equirectangular projection is often used in cartography because it is easy to construct and to understand. It also preserves the shape of objects near the equator, which makes it a good choice for displaying data related to equatorial regions. However, it distorts the size and shape of objects towards the poles, making it less accurate for displaying data in high-latitude regions.
Equirectangular projection is commonly used as a standard for many online mapping services such as Google Maps and OpenStreetMap. It is also often used as a starting point for creating other types of maps, such as thematic maps or choropleth maps, where data is displayed by coloring or shading different areas of the map based on specific criteria.