Equal-area projections are a type of map projection used in cartography where the surface area of all mapped features is preserved, making it useful for visualizing the true size of countries and continents. There are several alternative names that can be used to describe equal-area projections, including equal-area map, equivalent map projection, or area-preserving map projection. Other terms used to describe the concept of equal-area projections include equiareal projection, homolographic projection, and globular projection. Regardless of the name used, the underlying principle of an equal-area projection is the preservation of the relative sizes of features on the map.