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Track: Cartography & Map Production
David McCulloch
U.S. Geological Survey
4710 Eisenhower Boulevard
Tampa, FL 33634
Telephone: 813-243-5800
Fax: 813-243-5806
E-mail: dmccullo@usgs.gov
Gregory Allord
Standardizing Cartographic Design and Symbology Through the Use of Abstract Cartographic Objects
Defining Issue: Many maps are included in U. S. Geological Survey publications documenting hydrologic studies in support of earth/science investigations. Although the USGS has publication conventions for cartographic features, the implementation of those standards is difficult. Often, the actual definition of the geometry of a particular symbol is either unknown, complicated, or time-consuming to implement. Additionally, some versions are inflexible and software dependent. GIS Solution: The USGS has implemented cartographic object abstraction. This combines the cartographic elements of point, line, area, and text symbolization and masks the details of how symbology is defined. This allows scientists and illustrators to use publication standard symbology by referring to the common name of a map feature. For example, instead of specifying the geometry for the dashed lines of a county boundary, a scientist or illustrator specifies a geographic data layer and the cartographic object called "county
boundary" to apply to that data layer. Methodology: Using object-oriented design, a set of abstract cartographic objects was developed. The objects include both the instructions or computer code to display objects, plus the data or geometry of the objects. The implementation of the objects as both computer code and data has several advantages over using traditional procedures to develop maps from geographic data layers: (1) allows casual users to more e.
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