GEOG281 Lecture Notes - Lecture 5: Spatial Database, Zero-Dimensional Space, Complex Representation

• School: University of Waterloo
• Department: Geography and Environmental Management
• Course: GEOG281
• Professor: Su Yin Tan

Document Summary

Spaial data models: models used for graphic representaion of geographic space. There are two types of gis data models: Space intervening between graphic eniies does not have to be stored. Points: zero dimensional objects (i. e. wells, sample locaions, trees) Lines/arcs: one dimensional objects, or linear features, made up of a series of interconnected points (i. e. roads, streams). A line starts and ends with a special point called a node. Points that make up the rest of a line are called verices. Polygons/area: two dimensional objects made up of a series of connected lines, where the staring point of a polygon is the same as the ending point (i. e. ields, lakes, forest) Vector data is ideally suited for computer mapping and spaial database management. Series of linked iles establishing explicit spaial topology (relaionships among map features) Lots of duplicaion, hence need for large storage space. Analogy: the data model is the map expressed as a list of cartesian (x,y) coordinates.