Maps in S.

The ability to draw geographical maps is an indispensable tool when analyzing or displaying geographically oriented data such as network data or census information. We describe a new map-producing mechanism integrated with the S system for data analysis. The map software features both line and area drawing, adaptation to plotting device resolution, map projections and a flexible user interface. The facility currently has a repertoire of three geographical databases, describing the national, state and county boundaries of the USA.