Map Scale is an important concept in GIS. If not fully understood, you will bring out the inaccuracies in your GIS data. For more about this see our Data Accuracy and Precision Page.
Menno-Jan Kraak, Cartographer:
The map scale expresses the ratio between distances in the map and those in reality. When a map displays a large area it is said to be a small scale map, and when a small area a large scale map.
Map Scale Reference Page, USGS, Water Resources of Idaho
GIS Map Scale Chart, U.S. Fish and Wildlife Service
Map Scale, Maps 101 - Topographic Maps, The Basics, Centre for Topographic Information
Guide to Map Scale, The University of Arizona Library
Shows how to convert from one scale to another