National Geologic Map Database

Development and management of science databases in support of societal decisionmaking and scientific research are critical and widely recognized needs. The National Geologic Mapping Act of 1992 and its subsequent reauthorizations stipulate that the USGS and the Association of American State Geologists (AASG) will create and maintain the National Geologic Map Database (NGMDB) as a national archive of spatially referenced geoscience data including geology, geochemistry, geophysics, paleontology, and geochronology. The Act further stipulates that all new information contributed to the NGMDB should adhere to technical and science standards developed as needed under the guidance of the NGMDB project.

This congressional mandate for State-Federal collaboration has proven invaluable, facilitating progress on many technical issues that would otherwise be much more difficult to achieve by separate efforts within the numerous agencies. The NGMDB’s long record of accomplishment owes a significant debt to its many collaborators, and to the institutions with which it interacts (see Appendix A in a previous Progress Report). At numerous meetings each year, technical plans and progress are reported, and discussion and comment is requested; these activities are recorded each year by a progress report in the Digital Mapping Techniques Proceedings.

From the guidance in the National Geologic Mapping Act, and through extensive discussions and forums with the geoscience community and the public, a general strategy for building the NGMDB was defined in 1995. Based on continued public input, the NGMDB has evolved from that concept to a set of resources that substantially help the Nation’s geological surveys to more efficiently provide standardized digital geoscience information to the public.

The NGMDB is a suite of related databases, products, and services including: (1) a catalog of all paper and digital geoscience maps and related reports of the Nation, and images of many of these maps and associated plates; (2) the U.S. Geologic Names Lexicon; (3) a database of geologic mapping in progress; (4) a prototype database of USGS biostratigraphic reports and related information; (5) image libraries of geologic and topographic maps; (6) a set of Web interfaces to permit access to these products; and (7) a set of standards and guidelines to promote more efficient management and use of spatial geoscience information. The NGMDB is a hybrid — some aspects are centralized and some are distributed, with the map information held by various cooperators (for example, the State geological surveys). Through a primary entry point on the Web, users can browse and query the NGMDB and obtain access to the information wherever it resides.

Status of the Nation's geologic map coverage

The status map shown below indicates the areas covered by geologic maps of intermediate and detailed scale; that is, maps of scale 1:100,000 to 1:24,000. As a result of this choice, many useful maps (for example, at scale 1:125,000, 1:250,000, etc.) are not shown; in the future, those maps will be shown at an interactive site, at which you'll be able to browse the status of geologic mapping at all scales and vintages. In the meantime, we invite you to browse this map, and learn about the status of geologic mapping during the past 130+ years; we also include brief notes on certain issues that influenced mapping during the decades. This status map evolved from results of a required annual computation of map coverage. Some background on the method is available.

Geologic maps serve a fundamental role in helping us to find natural resources, evaluate natural hazards, solve land-use problems, and understand Earth's history. To address these issues, systematic geologic mapping of the United States has been conducted under many programs in Federal and State agencies, Universities, and other organizations since the 19th century. For example, in the period centered on ca. 1895-1920, the USGS began to compile the "Geologic Atlas of the United States." It's notable that the scientific and cartographic standards developed to guide that mapping have, with modest revision, endured to this day and formed a basis for the continued, systematic mapping of the Nation.

Because geologic mapping has been conducted by many organizations, to address a wide variety of economic and societal issues that have changed in focus over the centuries, these maps vary significantly in the type of information they provide. These differences present a real challenge to the preparation of "status" maps that purport to show geologic map coverage – if all geologic maps are not alike in content, scale, detail, vintage, or currency, which then should be included in a status map? By what criteria should we differentiate or classify geologic maps for this purpose?

Interactive image showing status of geologic mapping over time

Reports of progress

The goals and progress for the National Geologic Map Database are provided below and in the annual reports that were published in the years 1995 through 2011. Most of those reports were published in the Digital Mapping Techniques (DMT) Proceedings volumes; exceptions (1995-1998) are noted. These Proceedings were not published after 2011. Since that time, NGMDB progress has continued to be reported at the DMT workshops, and at various annual scientific meetings.

Annual reports: 2011 — 2010 || 2009 || 2008 || 2007 || 2006 || 2005 || 2004 || 2003 || 2002 || 2001 || 2000 || 1999 || 1998 (GIS Proceedings) || 1998 || 1997 (Geotimes) || 1995 (Geotimes) || 1995 (unpublished).

Status of tasks and database components
Map Catalog

Goal —To serve as a comprehensive resource for information about paper and digital geoscience maps and reports on the Nation's geology, by all publishers. The Map Catalog is not limited to geologic maps — because natural resource and hazard information also is critical in order to address various societal issues, many types of geoscience publications are included. Close collaboration between the state geological surveys and USGS ensures that the Map Catalog is a distributed archive, providing the guidance needed for users to find the authoritative source for each publication.

Status —The Map Catalog contains information on about 104,000 maps and reports published from the early 1800s to the present day, by more than 640 agencies, universities, associations, and private companies. This information includes a bibliographic citation, descriptive keywords, bounding coordinates, links to online publications and to sales offices, and online viewable (and in many cases, downloadable) images of geoscience maps. For two-thirds of the publications, a link to a digital version is provided. More than sixty percent of the publications in this Map Catalog focus on geoscience topics other than geologic mapping. Search and browsing of the geologic map portion of the Catalog is supported by a map-based interface, "mapView," the purpose of which is to portray the Nation's vast collection of geologic maps published by the USGS, the state geological surveys, and others. The status of mapView is noted below.


Goal —Develop and maintain the U.S. Geologic Names Lexicon (Geolex). This lexicon serves as a foundation for the Nation’s geologic mapping science, providing standardized, essential information for each stratigraphic unit (for example, various usages of a geologic unit's name, type locality, description, etc.).

Status —Bibliographic citations from the Map Catalog and Geolex were merged into a single database in order to provide integrated search and reporting of publications, geologic names, and study area footprints. Geolex is regularly updated to reflect changes in stratigraphic nomenclature, especially those geologic names endorsed by State Geological Surveys. Work continues on evaluation of the many and disparate sources for Geolex (e.g., electronic listings of geologic names, published lexicons, correlation charts, new publications), in order to improve the content. Geolex is supported by Web pages that provide access to published State and regional lexicons and correlation charts, and by the unpublished Geologic Names Committee’s (GNC) card file of notes and additional relevant citations for geologic names (~220,000 cards).


Goal —In an interactive, map-based Web interface, show a significant part of the NGMDB’s national archive of geoscience information – that is, the systematic, regional mapping of the bedrock and surficial deposits. MapView is intended as an introduction to the geologic maps of the Nation, and is integrated with the NGMDB Map Catalog, where other geologic maps, and maps and reports for related geoscience themes, are available.

Status —More than 17,000 geologic maps of the 50 States and U.S. Territories and Possessions have been georeferenced, and are available for viewing in mapView; further information for each map is available via a hyperlink to that record in the Map Catalog. Significant effort is now directed toward an overhaul of the codebase and interface in order to support use on mobile devices. Concurrently, mapView's content is being evaluated with the goal of adding all new, and many older, geologic maps to this interface.


Goal —In an interactive, map-based Web interface, facilitate quick, easy access to one of USGS's most important and useful products, the topographic map. In 1879, the USGS began to map the Nation's topography. This mapping was done at different levels of detail, in order to support various land use and other purposes. As the years passed, the USGS produced new map versions of each area. TopoView shows the many and varied older maps of each area, and so is useful for historical purposes—for example, the names of some natural and cultural features have changed over time, and the 'old' names can be found on these historical topographic maps. TopoView also shows the most recently published topographic maps, released in the "US Topo" series.

This interface was created by the National Geologic Map Database project (NGMDB), to increase accessibility to the topographic maps produced by the USGS National Geospatial Program (NGP). Geologic mapping and topographic mapping at the USGS have a long tradition together (see 1888 report).

Status —The maps shown through topoView are from both the USGS’s Historical Topographic Map Collection (HTMC) and the US Topo program. The HTMC project began scanning topographic maps in 2011, to provide a digital repository of USGS 1:250,000 scale and larger (more detailed) maps printed between 1884 (the inception of the topographic mapping program), and 2006. Currently, there are more than 178,000 maps in the HTMC. Under the US Topo program, 1:24,000-scale topographic maps are produced by entirely digital methods, on a three-year replacement cycle. The NGP is accurately cataloging and creating metadata to accompany high-resolution, georeferenced digital files of each of these printed maps. NGP offers these maps as GeoPDFs, through The National Map and the USGS Store. TopoView offers additional formats (GeoTIFF, JPEG, and KMZ) to address various user needs.

Mapping In Progress

Goal —Show areas that are now being geologically mapped, and whom to contact for more information. This database shows information about mapping by the U.S. Geological Survey (USGS), State geological surveys, and academia under the National Cooperative Geologic Mapping Program. Ideally, it eventually will include geologic mapping in progress that is funded by other programs in USGS and elsewhere.

Status —In late 2019, the Mapping In Progress database was redesigned and populated, and the Web site was reopened.

Archive of unpublished information

Extensive collections of unpublished paleontologic reports, field maps and notes, and other materials are being curated and, when warranted, scanned in order to increase their accessibility. This work has been undertaken in order to address the NGMDB's mandate as a National Archive of geologic map information.

Nationwide geologic maps

For many societal and scientific applications, detailed geologic map information of local areas is essential, and the National Geologic Map Database provides access to that information. Regional- and national-scale maps also are essential for many purposes — such maps provide a regional geologic context for the detailed map information, help to inform regional planning decisions, and serve as an educational resource.

To support this need, the National Geologic Map Database project has developed national and regional geologic maps and databases, as described below. Compilation of additional maps is planned, with focus on subsurface geologic units and representation of the Earth's upper crust in three dimensions.

Geologic Map of North America shows the geology of a significantly large area of the Earth, centered on North and Central America and including the submarine geology of parts of the Atlantic and Pacific Oceans. The NGMDB project assisted in production of this map, and created the database. Files and other resources are available here.

Map Database for Surficial Materials in the Conterminous United States shows the mostly unconsolidated blanket of sediments that overlie bedrock. In places, they exceed 1000 ft in thickness. These materials are significant because they directly underlie most human activities. The NGMDB project co-compiled the map, and created the database.

Database for Map Showing the Thickness and Character of Quaternary Sediments in the Glaciated United States East of the Rocky Mountains The NGMDB project converted the digital files for this map to a modern format, thereby making it useful again in GIS software.

Standards and guidelines

Within an agency, program, or a project, there generally are standard practices for the preparation and distribution of geologic information. Widely-accepted standards and guidelines for the format, content, and symbolization of such information are critical to the broader acceptance, comprehension, and use of geoscience information by the non-professional and professional alike. Many established and draft standards and guidelines for geologic map preparation and production are listed at the NGMDB standards site. The status of two significant efforts in which the NGMDB project is involved are provided below.

GeMS this is the standard format for geologic map publications funded by the U.S. Geological Survey's National Cooperative Geologic Mapping Program (NCGMP).

FGDC Geologic Map Symbolization Standard the NGMDB project serves on behalf of the USGS to coordinate maintenance of this standard. Revisions to the Standard will be considered based on suggestions and guidance from map publishers and users.

Long term plan for a distributed database of vector, geologic map data

From the NGMDB project’s origin in 1995 it has been the generally held vision, by users and colleagues alike, that the National Geologic Map Database should, principally, be a repository of GIS data for geologic maps and related information, managed in a complex system distributed among the USGS and State geological surveys. The envisioned system would offer public access to attributed vector and raster geoscience data, and allow users to perform queries online, create derivative maps, and download source and derived map data. Further, all information in the database would retain metadata that clearly indicates its source (that is, who created a particular contact, fault, or delineation of a map unit contained in the database, and how the feature or attributes were later modified by further study). However, that entails a complex, long-term effort whose fully realized form is difficult to predict because it would rely on: (1) a large amount of standardized data; (2) the rate of technological change; (3) skilled computer-oriented personnel (in high demand and, therefore, in short supply); (4) the ability for all participating agencies to reach consensus on the approach; and (5) unwavering commitment by the agencies to maintain and evolve the system, together.

Bearing this in mind, the NGMDB project has focused principally on the "building blocks" (for example, the Map Catalog, Geolex, standards development) and made only a limited, systematic effort to address this long-term goal through prototypes. Each prototype addressed aspects of the database design, implementation in GIS software (for example, ArcGIS), standard science terminologies, and software tools; some are briefly described in NGMDB progress reports such as this one for 2011-2012. In 2019, interest in developing this database was renewed. Planning is now underway for NGMDB's implementation.

Documentation of NGMDB database and workflow

The NGMDB project has completed most of the comprehensive redesign of its database and Web site, which has gradually evolved since its introduction in 1996. While work on the remaining aspects of this redesign proceed, we also are compiling technical documentation that will become available here and also possibly in a published USGS report. Documentation will include details on the NGMDB's underlying database and methods for workflow (e.g., creating citations, error-checking, image processing). We anticipate this will begin to become available in 2021.