As a subject it can generally be divided into two major components: physical geography, concerning Earth system processes, and human geography, concerning human activities across the Earth. There is a large degree of overlap between these two, and geography is regarded as the subject that bridges the arts and the sciences.
Physical geography helped establish the absolute location of towns, countries, landmasses and oceans. A typical way of identifying a given place's location is to express it as co-ordinates in latitude and longitude. Due to the curvature of the earth, the co-ordinates represent the projection of a location in three dimensions (i.e. on the surface of the earth) to two dimensions (i.e. a point on a map). As the earth is not perfectly spherical, the reliance upon a single projection for the entire world is unreliable and would result in distortions and inaccuracies (relative to the place's location on the earth). For this reason, there are many types of map projections, such as Lamberts Conformal Conic and Mercator projection. Similar to other measurements (such as length), a given geographic co-ordinate can be expressed in different ways, such as decimal degrees (e.g. 40.718119,-74.003906 for New York) or degrees, minutes and seconds (e.g. 40° 43' 5.2284", -74° 0' 14.0616").
An example of human geography is studying the placement of flowers by friends and relatives of those who have died in car accidents, at the site of the accident itself.