ABSTRACT

This chapter describes the main types of geographic information (GI) and how they are used, which is an essential element in the understanding of GI. GI is often treated in a much narrower sense, as information that has explicit location data associated with it, most often geometry that relates to a particular geographic coordinate system. In raster form, GI is represented as an array of cells, with each pixel representing a value and the position of each pixel corresponding to an area on Earth’s surface. GI can also be modeled topologically and mereologically. Topology expresses the spatial relationships that exist between different objects, and mereology describes the whole–part relationships. Textual descriptions are quite simply that: descriptions of the landscape, place, or other geographical feature. A digital feature model is a representation of the geography of an area, specifically discrete landscape features and their relationships to each other, typically constructed using vector and network data.