Most geological knowledge is applied in a spatial context. Thus, in order to consider the implications of geologic processes on humans or humans on their geologic environment, you must define that context. The tools which we use are aerial photographs, maps, and site-specific documents.
Aerial photographs are the base source of information for all modern maps.
Sophisticated plotters generate topography from the parallax, or apparent difference in spacing with differing elevation, of aerial photographs. Vegetation, streams, and human artifacts such as buildings and roads are interpreted from the photos. It is important to realize that even a detailed topographic map is an interpretation of reality, not reality itself. Topographic maps are the fundamental tool for location. The most common characteristics are the type of bedrock, the age of bedrock, and features implying deformation, such as tilts, folds, and faults.