Geography as a discipline can be split broadly into two main sub fields: human geography and physical geography. The former focuses largely on the built environment and how space is created, viewed and managed by humans as well as the influence humans have on the space they occupy. This may involve cultural geography, transportation, health, military operations, and cities. The latter examines the natural environment and how the climate, vegetation and life, soil, oceans, water and landforms are produced and interact. Physical geography examines phenomena related to the measurement of earth. As a result of the two subfields using different approaches a third field has emerged, which is environmental geography. Environmental geography combines physical and human geography and looks at the interactions between the environment and humans. Other branches of geography include social geography, regional geography, and geomatics.