a map showing planimetric, topographic, geologic, political, or cadastral information that may appear in many different types of maps —note 1. the base map information is drawn with other types of changing thematic information —see cadastre —note 2. base map information may be as simple as major political boundaries, major hydrographic data, and major roads —note 3. the changing thematic information may be bus routes, population distribution, caribou migration routes, etc.This definition last updated 07/16/2008