Geography is a branch of science that deals with the study of the Earth, its land and other physical features, environment and its relationship to human life. It has two main sub-fields : physical geography and human geography. Physical geography deals with Earth's climate, physical structure, atmosphere, soil, rock, water and related natural processes. Human geography focuses on the study of human interaction with the environment, its cultural, social and economic aspects. Maps, geographic information systems, remote sensing satellites and statistical methods are key tools used in the field of geography.