Land cover
Land cover is the physical material at the surface of Earth. Land covers include grass, asphalt, trees, bare ground, water, etc. Earth cover is the expression used by ecologist Frederick Edward Clements that has its closest modern equivalent being vegetation. : 52  The expression continues to be used by the United States Bureau of Land Management.There are two primary methods for capturing information on land cover: field survey, and analysis of remotely sensed imagery. Land change models can be built from these types of data to assess changes in land cover over time.