Physical geography (also known as geosystems or physiography) is one of the two major subfiels of geography. Physical geography focuses on understanding the processes and patterns in the natural environment, as opposed to the built environment which is the domain of Human geography. Within the body of physical geography the Earth is often split either into several spheres or into different environments, with the main spheres being the; Atmosphere, Biosphere, Cryosphere, Geosphere, Hydrosphere, Lithosphere and Pedosphere. Within physical geography there are various fields of study, mainly but not exclusively focusing on the spheres of the earth. Research in physical geography is often interdisciplinary and uses the systems approach.