Digital Mapping Techniques '99 -- Workshop Proceedings
U.S. Geological Survey Open-File Report 99-386

The National Geologic Map Database -- A Progress Report

By David R. Soller1 and Thomas M. Berg2

1U.S. Geological Survey
908 National Center
Reston, VA 20192
Telephone: (703) 648-6907
Fax: (703) 648-6937

2Ohio Geological Survey
4383 Fountain Square Dr.
Columbus, OH 43224
Telephone: (614) 265-6988
Fax: (614) 268-3669

The Geologic Mapping Act of 1992 and its reauthorization in 1997 (PL105-36) requires that a National Geologic Map Database (NGMDB) be designed and built by the U.S. Geological Survey (USGS), with the assistance of the state geological surveys and other entities participating in the National Cooperative Geologic Mapping Program. The Act notes that the NGMDB is intended to serve as a "national archive" of geologic maps, to provide the information needed to address various societal issues. The Act required the NGMDB to also include the following related map themes: geophysics, geochemistry, paleontology, and geochronology. In this progress report, the term ìgeoscienceî is used to refer to these five map themes.

In mid-1995, the general stipulations in the Act were addressed in the proposed design and implementation plan developed within the USGS and the Association of American State Geologists (AASG). This plan was summarized in Soller and Berg (1995). Because many maps are not yet in digital form and because many organizations produce and distribute geologic maps, it was decided to develop the NGMDB in several phases. The first two phases are addressed here. The first and most fundamental phase is a comprehensive, searchable catalog of all geoscience maps in the United States, in either paper or digital format. The users, upon searching the NGMDB catalog and identifying the map(s) they need, are linked to the appropriate organization for further information about how to procure the map. (The organization could be a participating state or federal agency, association, or private company.) The map catalog is presently supported by two databases developed under the NGMDB project: 1) GEOLEX, a searchable geologic names lexicon; and 2) Geologic Mapping in Progress, which provides information on current mapping projects, prior to inclusion of their products in the map catalog. The second phase of the project focuses on public access to digital geoscience maps, and on the development of digital map standards and guidelines needed to improve the utility of those digital maps.

In late 1995, work began on phase one. The formation of several Standards Working Groups in mid-1996 initiated work on phase two. Progress was summarized in Soller and Berg (1997 and 1998). At the Digital Mapping Techniques ë98 and ë99 workshops, a series of presentations and discussion sessions provided updates on the NGMDB and, specifically, on the activities of the Standards Working Groups. This report summarizes progress since mid-1998. Further and more current information may be found at the NGMDB project-information Web site, at The searchable database is available at


The Map Catalog

he catalog now contains bibliographic information for nearly all formal series USGS maps, USGS maps contained in book publications, and maps from the USGS open-file series. The catalog is estimated to be about 50% complete, and contains georeferenced information for about 90% of all USGS maps (about 18,500 in the catalog) and 6% of state geological survey maps. This represents more than a six-fold increase in information since last year. Through development of a Web-based data-entry form, and reformatting and enhancements to information contained in existing State publications listings, we are working with nine state geological surveys (Illinois, Indiana, Louisiana, Ohio, Oklahoma, Oregon, Vermont, West Virginia, and Wyoming) and one University (Stanford) to bring their map information into the catalog. Entry of state geological survey publications is now a top priority.

Geologic Names Lexicon

In April, 1998, an on-line, geologic-names lexicon, GEOLEX, became available at the NGMDB Web site. This lexicon is under construction, and is estimated to be about 75% complete. At present, GEOLEX contains 90% of the geologic names found in the most recent listing of USGS-approved geologic names; this listing was published in 1996 as USGS Digital Data Series DDS-6, revision 3. Prior to loading into GEOLEX, the information on DDS-6 was consolidated, revised, and error-corrected. Much of the remaining work needed to complete GEOLEX will focus on resolving name conflicts, adding reference summary and other information for each entry, and incorporating geologic names not found on DDS-6 but recorded in the geologic names card catalog at USGS Headquarters. GEOLEX is intended to be the comprehensive, authoritative listing of geologic names approved for usage by the USGS, and is available as a resource for geologic mappers nationwide. Many state geological surveys have been registering new geologic names with the USGS for decades, and are encouraged to continue under GEOLEX, through a Web-based application form.

Geologic Mapping in Progress Database

To provide users with information about current mapping activities at 1:24,000- and 1:100,000-scale (1:63,360- and 1:250,000-scale in Alaska), a Geologic Mapping in Progress Database has been developed. In 1998, its scope and design were proposed to the AASG and a prototype database was built. The database has been expanded to contain information about 1998 mapping activities, and a Web interface to the database has been designed and built. It is available through the NGMDB home page,

Related Databases

Work has begun on a National Paleontologic Database and a set of Web pages to permit searches and to provide general-interest information in support of the Database. In the coming year, efforts will be made to provide links from the NGMDB to related databases under construction (for example, for geophysical and geochemical information).


Most efforts related to phase two have been directed toward the development of standards and guidelines needed to help National Cooperative Geologic Mapping Program participants more efficiently produce digital geologic maps, and to produce those maps in a more standardized and common format among the various map-producing agencies. Significant progress has been made toward developing some of these standards and guidelines, and increased efforts will be devoted in the coming year toward improving public access to digital maps.

Standards Development

The following summaries concern activities of the AASG/USGS Standards Working Groups formed in mid-1996. General information about the Working Groups, and details of their activities, are available at <>.

Geologic Map Symbols

A draft standard for geologic map line and point symbology and map patterns and colors, published in a USGS Open-File Report in 1995, was revised by the NGMDB project team and members of the USGS Western Region Publications Group and was circulated for internal review in late 1997. The revised draft is now being prepared as a proposed Federal standard, for consideration by the Federal Geographic Data Committee (FGDC). We anticipate that the draft will be submitted to the FGDC in 1999; informal USGS release of the map symbols and patterns in Postscript format also is anticipated in 1999. To make these symbols more widely available to the GIS community, we have negotiated with Environmental Systems Research Institute, Inc., a cooperative plan to develop an Arc/Info and ArcView version of the symbols and patterns; for more information, see

Digital Mapping

The Data Capture Working Group has coordinated three annual ìDigital Mapping Techniquesî workshops for state, federal, and Canadian geologists, cartographers, and managers. These meetings have been highly successful, and have resulted in adoption within agencies of new, more efficient techniques for digital map preparation, analysis, and production. The most recent workshop, held in Madison, Wisconsin, and hosted by the

Wisconsin Geological and Natural History Survey, was attended by representatives of 42 state, federal, and Canadian agencies and private companies. The workshop proceedings are published (Soller, 1997, 1998, and this volume) and served on-line (;; and Copies of the Proceedings may be obtained from Soller or Berg.

Map Publication Requirements

Through the USGS Geologic Division Information Council, one of us (Soller) led development of the USGS policy ìPublication Requirements for Digital Map Productsî (enacted May 24, 1999). A less USGS-specific version of this document has been developed by the Data Information Exchange Working Group and presented for technical review at a special session during the Digital Mapping Techniques ë99 workshop (this volume). The revised document (entitled ìProposed Guidelines for Inclusion of Digital Map Products in the National Geologic Map Databaseî) has been submitted to the AASG Digital Geologic Mapping Committee for consideration as a guideline for newly-produced maps available through the NGMDB.


The Metadata Working Group developed its final report in 1998. The report provides guidance on the creation and management of well-structured formal metadata for digital maps (see The report contains links to metadata-creation tools and general discussions of metadata concepts (see, for example, the metadata-creation tools, ìMetadata in Plain Languageî and other helpful information at

Geologic Map Data Model

Following numerous presentations, discussions, and progress reports (for example, Raines and others, 1997), in October, 1997, the Working Group posted to the NGMDB projectís Web site for public comment a report describing the proposed standard data model. To permit thorough evaluation of the data model, the concepts and specifications described in that report must be translated into software tools that 1) organize and manage the geologic map information in the data-model format, and 2) offer a user-friendly interface for data entry and analysis. The Working Group began building some prototype tools in mid-1997. Through presentations and discussions with potential users, the tools were refined.

The data model and tools were presented for discussion in a special session at the Digital Mapping Techniques í98 workshop in late May, 1998. A number of attendees from the state geological surveys expressed interest in helping to refine the model and develop it into a geoscience-community standard. It was agreed that an extended period of evaluation among the states and USGS would begin as soon as possible.

At a three-day workshop in June, 1998, the first formal review of the data model was conducted. The workshop was attended by 28 members of the USGS, state geological surveys, and the federal and provincial surveys of Canada. An overview of the conceptual model and software tools was followed by a hands-on session and facilitated discussion. The workshop conclusions were to: 1) proceed with development of the data model and software tools; 2) broaden the participation in its further development; 3) begin the extended period of on-site evaluation at state, provincial, and federal surveys; and 4) work toward adoption of the data model as a national standard.

To facilitate the review and discussion of the data model after the June workshop, a Web conference was developed (see Discussion topics include: 1) general conceptual issues related to the data model and geologic mapping; 2) specific problems with the data model; 3) development of standard geologic terms; and 4) software tools. This site, and the NGMDB projectís Web site, also offer access to the data model report and software tools.

The workshopís technical review of the data model signaled completion of the Data Model Working Groupís task. In late 1998, a mechanism to coordinate the continued development of the data model was proposed to the USGS, AASG, and the Geological Survey of Canada. This mechanism, a Data Model Steering Committee, was accepted in early 1999 and the first meeting was held soon thereafter at the USGS National Center. The Steering Committee is now forming numerous Technical Teams to address discrete tasks deemed necessary to further development and adoption of the data model. These Technical Teams will address issues such as: the inclusion of standard scientific terminology in the model; refinement of the conceptual data model; and development of software tools. Before the Technical Teams begin work, the Steering Committee will contact various users of digital geologic maps and conduct a requirements analysis, to provide information on how they use, or would like to use, digital maps; this information then will help guide the activities of the Technical Teams. Information about the Steering Committee and Technical Teams can be found at


Raines, G.L., Brodaric, Boyan, and Johnson, B.R., 1997, Progress reportóDigital geologic map data model, in David R. Soller, ed., Proceedings of a workshop on digital mapping techniques: Methods for geologic map data capture, management, and publication: U.S. Geological Survey Open-File Report 97-269, p. 43-46,

Soller, D.R., editor, 1997, Proceedings of a workshop on digital mapping techniques: Methods for geologic map data capture, management, and publication: U.S. Geological Survey Open-File Report 97-269, 120 p.

Soller, D.R., editor, 1998, Digital Mapping Techniques '98 -- Workshop Proceedings: U.S. Geological Survey Open-File Report 98-487, 134 p.

Soller, D.R., and Berg, T.M., 1995, Developing the National Geologic Map Database: Geotimes, v. 40, no. 6, p. 16-18.

Soller, D.R., and Berg. T.M., 1997, The National Geologic Map Database -- A progress report: Geotimes, v. 42, no. 12, p. 29-31.

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