PLEASE NOTE: This now-approved 'FGDC Digital Cartographic Standard for Geologic Map Symbolization (PostScript Implementation)' officially supercedes its earlier (2000) Public Review Draft version (see 'Earlier Versions of the Standard' below).
In August 2006, the Digital Cartographic Standard for Geologic Map Symbolization was officially endorsed by the Federal Geographic Data Committee (FGDC) as the national standard for the digital cartographic representation of geologic map features (FGDC Document Number FGDC-STD-013-2006). Presented herein is the PostScript Implementation of the standard, which will enable users to directly apply the symbols in the standard to geologic maps and illustrations prepared in desktop illustration and (or) publishing software.
The FGDC Digital Cartographic Standard for Geologic Map Symbolization contains descriptions, examples, cartographic specifications, and notes on usage for a wide variety of symbols that may be used on typical, general-purpose geologic maps and related products such as cross sections. The standard also can be used for different kinds of special-purpose or derivative map products and databases that may be focused on a specific geoscience topic (for example, slope stability) or class of features (for example, a fault map). The standard is scale-independent, meaning that the symbols are appropriate for use with geologic mapping compiled or published at any scale. It will be useful to anyone who either produces or uses geologic map information, whether in analog or digital form.
Please be aware that this standard is not intended to be used inflexibly or in a manner that will limit one's ability to communicate the observations and interpretations gained from geologic mapping. In certain situations, a symbol or its usage might need to be modified in order to better represent a particular feature on a geologic map or cross section. This standard allows the use of any symbol that doesn't conflict with others in the standard, provided that it is clearly explained on the map and in the database. In addition, modifying the size, color, and (or) lineweight of an existing symbol to suit the needs of a particular map or output device also is permitted, provided that the modified symbol's appearance is not too similar to another symbol on the map. Be aware, however, that reducing lineweights below .125 mm (.005 inch) may cause symbols to plot incorrectly if output at higher resolutions (1800 dpi or higher).
For guidelines on symbol usage, as well as on color design and map labeling, please refer to the standard's introductory text. Also found there are informational sections covering concepts of geologic mapping and some definitions of geologic map features, as well as sections on the newly defined concepts and terminology for the scientific confidence and locational accuracy of geologic map features.
More information on both the past development and the future maintenance of the FGDC Digital Cartographic Standard for Geologic Map Symbolization can be found at the FGDC Geologic Data Subcommittee website (http://ngmdb.usgs.gov/fgdc_gds/).
Earlier Versions of the Standard
Additional publication details
USGS Numbered Series
FGDC Digital Cartographic Standard for Geologic Map Symbolization (PostScript Implementation)