John Gerth, of the computer science department at Stanford, sent a link to a powerful illustration, by Latoya Egwuekwe, of the spreading effects of unemployment across the country during this ...

Geographic Information Systems (GIS) is specialist software that links geographical data with a map. Geographic Information Systems (GIS) enables users to add layers to show different information and ...

The associations that may be discovered by map comparison are influenced by the nature of the map features being compared and by the criteria used for making the comparisons. The criteria of identity ...

The map areas use the default pattern, which is a solid fill that rotates through the colors list. Because the colors list is specified in the GOPTIONS statement, all colors are used in the rotation.

Thematic map effectiveness can be defined only in terms of specific user requirements. Consideration of common requirements results in four criteria by which may effectiveness is evaluated: ...