equirectangularprojektiolla

Equirectangular projection is a simple, cylindrical map projection. It is also known as the equidistant cylindrical projection, the equidecimal projection, the plate carrée projection, or the geographic projection. In this projection, lines of longitude are projected as parallel vertical lines, and lines of latitude are projected as parallel horizontal lines. The distance between these lines is constant in both directions.

The equirectangular projection is formed by mapping the longitude and latitude of the globe directly to Cartesian coordinates. Specifically, x = R * longitude and y = R * latitude, where R is a constant representing the radius of the sphere. This results in a rectangular grid where the grid lines of latitude and longitude are equally spaced in both the horizontal and vertical directions. This makes it very easy to calculate distances and areas on the map, assuming the Earth is a perfect sphere.

However, this equal spacing leads to significant distortion, particularly near the poles. Areas at higher latitudes appear greatly stretched horizontally, making them appear much larger and wider than they actually are relative to equatorial regions. Greenland, for instance, is depicted as being much larger than Africa, despite Africa being about 14 times its size in reality. Conversely, areas near the equator are depicted with minimal distortion.

Despite its distortions, the equirectangular projection is widely used for its simplicity and ease of use, especially in digital contexts. It is the standard projection for panoramic images, such as those used in virtual reality and Google Street View. It is also frequently used for displaying global climate data and for creating raster world maps because it is easy to convert to and from other projections.