Maps allow us to convey information and findings that are difficult to express verbally. Maps can also be used to convince and persuade, or even propagandize. When we are trying to communicate a spatial relationship , we want our description to evoke a similar image in another persons mind. The defined dimensional relationship between reality and the map is called scale .
Maps portray only the information that's been chosen to fit the use of the map.
Classification and simplification make data easier to understand. The selection and design of these symbols greatly effects the communicability of the map. Cannot determine quantity. Ex. locations of different types of recreational areas in AZ or rest stops along I-8. Map scale has tremendous consequences on map design scale, symbolization, and map projection are all inter-connected.