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Digital Mapping Techniques '00 -- Workshop Proceedings
U.S. Geological Survey Open-File Report 00-325

Development and Public Review of the Draft "Digital Cartographic Standard for Geologic Map Symbolization"

By David R. Soller1 and Taryn Lindquist2

1U.S. Geological Survey
908 National Center
Reston, VA 20192
Telephone: (703) 648-6907
Fax: (703) 648-6937
  2U.S. Geological Survey
345 Middlefield Rd, MS 951
Menlo Park, CA 94025
Telephone: (650) 329-5061
Fax: (650) 329-5051

From May 19 through September 15, 2000, the Federal Geographic Data Committee's Geologic Data Subcommittee is conducting a public review of a proposed digital cartographic standard for geologic map symbolization. [The Geologic Data Subcommittee of the Federal Geographic Data Committee (FGDC) is responsible for coordination of geologic data-related activities among Federal agencies. The Subcommittee promotes the collection, use, sharing, and dissemination of geologic map information.] Comments and guidance are welcomed from all interested parties including members of the general public, private companies and consultants, state geological surveys, and other government agencies. After the public review, all comments will be considered and the draft will be revised accordingly. If all comments have been addressed to the FGDC's satisfaction, the revised draft then will be approved as a Federal standard.


This draft standard is intended to provide to the Nation's producers and users of geologic-map information a single, modern standard for the digital cartographic representation of geologic features. The objective in developing this national standard for geologic map symbols, colors, and patterns is to aid in the production of geologic maps and related products, as well as to help provide maps and products that have a consistent appearance.

If approved by the FGDC following the public review period, this draft standard will apply to geologic-map information published by the Federal government in both offset-print and plot-on-demand formats. It also is suitable for use in electronic publications (for example, in a Portable Document Format (PDF) file) and for display by computer monitors. Non-Federal agencies and private companies that produce geologic-map information are urged to adopt this standard as well.


This new draft standard has been developed by members of the USGS Geologic Division's Western Publications Group and National Geologic Map Database (NGMDB) project (Table 1). It draws heavily upon previous work by USGS geologic and cartographic personnel (U.S. Geological Survey, ca. 1975 and 1995), and the standards-development group gratefully acknowledges their contributions. In particular, we acknowledge Mitchell Reynolds (USGS, retired) for leading the preparation of the previous draft (U.S. Geological Survey, 1995).

Table 1. Preparers of This Draft Standard. Unless otherwise noted, each individual contributed to both
the Working Draft and the Public Review Draft.
David R. Soller (USGS; Chief, National Geologic Map Database)--Coordinator, FGDC draft standard development.

Taryn A. Lindquist (USGS; Digital Map Specialist, Western Publications Group)--Editor and compiler, FGDC draft standard document; coordinator, PostScript and ArcInfo implementations; designer, line symbols for PostScript and ArcInfo implementations.

Sara Boore (USGS; Publication Graphics Specialist, Western Publications Group)--Designer, FGDC draft standard document, point and line symbols, color charts and patterns for PostScript implementation. F. Craig Brunstein (USGS; Geologic Map Editor, Central Publications Group)--Technical reviewer, FGDC Working Draft.

Alessandro J. Donatich (USGS; Geologic Map Editor, Central Publications Group)--Technical reviewer, FGDC Working Draft.

Kevin Ghequiere (USGS; Cartographer, Western Publications Group)--Designer, patterns for PostScript implementation.

Richard D. Koch (USGS; Digital Map Specialist, Western Publications Group)--Designer, point symbols for ArcInfo implementation, geologic age symbol font.

Diane E. Lane (USGS; Geologic Map Editor, Central Publications Group)--Technical reviewer, FGDC Working Draft.

Susan E. Mayfield (USGS; Publication Graphics Specialist, Western Publications Group)--Designer, FGDC draft standard document, color charts and patterns for PostScript implementation.

Kathryn Nimz (USGS; Digital Map Specialist, Western Publications Group)--Designer, patterns for PostScript and ArcInfo implementations.

Glenn Schumacher (USGS; Publication Graphics Specialist, Western Publications Group)--Designer, bar scales, mean declination arrows, and quadrangle location maps.

Stephen L. Scott (USGS; Publication Graphics Specialist, Western Publications Group)--Designer, FGDC draft standard document, point symbols and line symbols for PostScript implementation.

Will Stettner (USGS; Cartographer, Eastern Publications Group)--Technical reviewer, FGDC Working Draft.

José F. Vigil (USGS; Motion Graphics Specialist, Western Publications Group) -- Designer, geologic age symbol font.

Jan L. Zigler (USGS; Geologic Map Editor, Western Publications Group)--Technical reviewer, FGDC Working Draft.

In 1995, a proposed standard was informally released by the USGS (U.S. Geological Survey, 1995). In 1996, this proposed standard was formally reviewed by geologists and cartographers in the USGS, the Association of American State Geologists (AASG), which represents the state geological surveys, and the FGDC's Geologic Data Subcommittee (GDS), which is composed mostly of representatives from Federal agencies that produce or use geologic map information. That review (Soller, 1996) indicated the need for some revision to the proposed standard prior to its consideration by the FGDC for adoption as a Federal standard.

In 1996, plans were outlined to create a revised and updated Federal standard, and the standards-development group was formed. A proposal to develop the revised standard was submitted by the FGDC's GDS (see, and the FGDC accepted that proposal in 1997. Later that year, the standards-development group produced a preliminary, beta version of the draft standard, which was circulated among selected USGS and state geological survey personnel for review. Comments were incorporated and, in 1999, the revised draft standard (Working Draft) was submitted to the FGDC's GDS for consideration. Upon review and subsequent approval by the GDS, the Working Draft was submitted to the FGDC Standards Working Group, which approved the document for public review, pending adoption of minor changes. The changes were made, and this new draft standard document (Public Review Draft) became available to the public for review and comment on May 19, 2000. The public review period will extend through September 15, 2000.


Upon completion of the 120-day public review period, comments to the Public Review Draft will be considered, and any necessary revisions will be made. The revised draft standard document then will be submitted to the FGDC for formal approval as the Federal standard for geologic map symbolization. After the standard is formally approved by the FGDC, the intention is that it will become a "living" standard -- that is, it will be maintained and revised as needed to reflect new mapping disciplines or evolving usage conventions. The initial release of the FGDC-approved standard document will be available in printed form and supplemented by an electronic (PDF) version. Thereafter, updates to the standard document will be reflected in an online version, which will become the authoritative reference.

To help users maintain an up-to-date hard-copy version of the standard document, the initial release will be printed in "loose-leaf" format. Subsequent updates to the standard document will be made available in PDF format only, which could then be printed on a local output device and inserted where appropriate into a loose-leaf binder.


Example of the standard
Figure 1. Example of the standard, from "Section 6 - Bedding."

In this new draft standard, descriptions, examples, cartographic specifications, and notes on usage are provided for a wide variety of symbols (see for example, figure 1) that may be used on typical digital geologic maps or related products such as cross sections. In the preparation of this standard, every effort was made to retain the original symbols and their specifications from the 1995 USGS proposed standard (U.S. Geological Survey, 1995); however, many updates have been incorporated into this new version. The number of symbols has increased significantly, from about 800 to almost 1200. Symbols are more logically grouped; some sections have been combined with others, and a few new sections have been added. A newly revised chart that shows a wide range of CMYK colors has been included. An offset-print version of this chart has been in use at the USGS for many years, and the variety of colors has proved to be sufficient for portraying complex geology shown on most maps, regardless of the output medium. In addition, a chart that shows commonly used geologic patterns has been added. The patterns themselves are similar to what was in the 1995 USGS proposed standard, but most have undergone lineweight changes to facilitate digital output at high resolutions. Table 2 lists the contents of the standard.

Table 2. Contents of the Standard.
1. Contacts, Key Beds, and Dikes
1.1 Contacts
1.2 Key Beds
1.3 Dikes
2. Faults
2.1 Faults (Vertical, Subvertical, Reverse, or Unspecified Offset or Orientation); Shear Zones; Minor Faults
2.2 Normal Faults
2.3 Strike-Slip Faults
2.4 Thrust Faults
2.5 Overturned Thrust Faults
2.6 Detachment Faults
3. Boundaries Located by Geophysical Surveys
3.1 Boundaries and Faults Located by Geophysical Methods
3.2 Geophysical Survey Lines and Stations
4. Lineaments and Joints
5. Folds
5.1 Anticlines; Antiforms
5.2 Asymmetric, Overturned, and Inverted Anticlines
5.3 Synclines; Synforms
5.4 Asymmetric, Overturned, and Inverted Synclines
5.5 Monoclines
5.6 Minor Folds; Boudinage
5.7 Free-Form Fold Symbology
6. Bedding
7. Cleavage
8. Foliation
8.1 Foliation and Layering in Igneous Rock
8.2 Foliation and Layering in Metamorphic Rock
9. Lineation
10. Paleontological Features
10.1 Fossil Localities; Biostratigraphic Zone Boundary
10.2 Fossil Symbols
11. Isopleths
11.1 Lines of Equal Physical or Chemical Properties
11.2 Geophysical and Structure Contours
12. Fluvial and Alluvial Features
13. Glacial and Glaciofluvial Features
14. Periglacial Features
15. Lacustrine and Marine Features
16. Eolian Features
17. Landslide and Mass-Wasting Features
18. Volcanic Features
19. Natural Resources
19.1 Veins and Mineralized Areas; Metamorphic Facies Boundary; Mineral Resource Areas
19.2 Areas of Extensively Disturbed Ground and Workings as Mapped Units
19.3 Mining and Mineral-Exploration Symbology
19.4 Mines and Underground Workings
19.5 Oil and Gas Fields; Wells Drilled for Hydrocarbon Exploration or Exploitation
20. Hazardous Waste Sites
21. Neotectonic and Earthquake-Hazard Features
22. Plate-Tectonic Features
23. Miscellaneous Uplift and Collapse Features
24. Terrestrial Impact-Crater Features
25. Planetary Geology Features
26. Hydrologic Features
26.1 Hydrography and Hydrologic Feature Identification Symbology
26.2 Water Wells
26.3 Water Gaging Stations
26.4 Quality-of-Water Sites
26.5 Springs
26.6 Miscellaneous Hydrologic Symbols
27. Weather Stations
28. Transportation Features
29. Boundaries
30. Topographic Features
31. Miscellaneous Map Elements
32. Pattern Chart (Plate B)
33. Suggested Stratigraphic-Age and Volcanic Map-Unit Colors
33.1 Stratigraphic-Age Map-Unit Colors
33.2 Volcanic Map-Unit Colors
34. CMYK Color Chart (Plate A)
35. Bar Scales
36. Mean Declination Arrows
36.1 Magnetic North, East of True North
36.2 Magnetic North, West of True North
37. Quadrangle Location Maps
37.1 Individual States; District of Columbia; Guam; Puerto Rico; U.S. Virgin Islands
37.2 Conterminous States
38. Geologic Age Symbol Font ("StratagemAge")


The draft standard is available at the GDS web site (, in PDF format. A paper copy also may be obtained upon request; ordering instructions are found at the web site.

Because this new standard is intended for use with digital applications, an electronic implementation of the Public Review Draft has been prepared in PostScript format, and it is informally released as a USGS Open-File Report (U.S. Geological Survey, 1999 ( This PostScript implementation will enable reviewers to directly apply the standard to geologic maps or illustrations prepared in desktop illustration and (or) publishing software. As the formally approved standard evolves, the PostScript implementation will be updated as well. Additionally, partial work on an ArcInfo (v. 7x) implementation has been completed, and this implementation may also be informally released as a USGS Open-File Report in the future. Information regarding updates to these and other implementation efforts will be posted on FGDC's GDS website,


Soller, D.R., 1996, Review of USGS Open-File Report 95-525 ("Cartographic and digital standard for geologic map information") and plans for development of Federal draft standards for geologic map information: U.S. Geological Survey Open-File Report 96-725, 12 p.,

U.S. Geological Survey, ca. 1975, Technical cartographic standards volume: unpublished U.S. Geological Survey internal standards document.

U.S. Geological Survey, 1995, Cartographic and digital standard for geologic map information: U.S. Geological Survey Open-File Report 95-525, 257 p.

U.S. Geological Survey, 1999, Public review draft -- digital cartographic standard for geologic map symbolization (PostScript implementation), prepared in cooperation with the Geologic Data Subcommittee of the Federal Geographic Data Committee: U.S. Geological Survey Open-File Report 99-430,

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Maintained by Dave Soller
Last updated 11.01.00