Digital Geologic Map Data Models
The Idaho Geological Survey has been producing geologic maps digitally since 1989. The Idaho Survey began to capture a database of basic geologic attributes associated with each geologic feature on a map in 1992 as part of its map digitizing process. Beginning in 1996 metadata, or information about the map and its sources, has been input for each 30 x 60 minute geologic map compilation. These attributed spatial data can be used in a Geographic Information System (GIS) to perform simple queries or analyses. However, to receive consistent and meaningful answers to complicated questions about the geology on a digital map, requires yet another database of map information derived from the map legend.
Taken together, the spatial map data, map legend, and metadata comprise a digital geologic map database. The design of these data sets and how they relate to one another to supply reasonable interpretations of the map is a digital geologic map data model.
Idaho Survey's Geologic Map Data Standards (2015)
The Idaho Geological Survey currently distributes geologic map data in two digital map standards: 1) The Idaho Geologic Map Data Model v3.1; and 2) NCGMP09, a new guideline created in 2009 for the publishing of digital (GIS) geologic map data. All new geologic map data will be distributed in the IGS variant of NCGMP09.
Idaho Geologic Map Data Model v3.1
This standard was created as a result of work done by the National Geologic Map Data Model Steering Committee in the early 2000’s. It is rich in attributes from the spatial to lithologic. The design of the database allows for two levels of map object tracking or coding: By 30' x 60' tile or statewide. The data standard was only adopted by Idaho and while information rich it is also labor intensive to update and maintain. Currently a large portion of north Idaho geology is stored in this format as an ESRI Geodatabase (See IGS publicationDGM-7).
Draft Standard Format for Digital Publication of Geologic Map (NCGMP09)
The great benefit of this standard is its simplicity. The standard is being adopted by many state surveys. All new IGS geologic map data will be distributed in a variant of NCGMP09 in parallel with published 30 x 60 geologic maps (for example, see IGS publication GM-49).
Freed, J.S. and Stanford, L.R., 2005, Map Production and Data Distribution the Idaho Way: An Update, in Soller, D.R., ed., Digital Mapping Techniques ’05—Workshop Proceedings: U.S. Geological Survey Open-File Report 2005-1428, p. 55-59.
Haugerud, R.A. , Richard, S.M. , Soller, D.R., and Thoms, E.E., Draft Standard Format for Digital Publication of Geologic Maps, Version 1.1, in D.R. Soller, ed., Digital Mapping Techniques '09-Workshop Proceedings: U.S. Geological Survey Open-File Report 2010-1335, p. 93-152, http://pubs.usgs.gov/of/2010/1335/pdf/usgs_of2010-1335_NCGMP09.pdf.
North American Geologic-Map Data Model Science Language Technical Team, 2004b, Report on progress to develop a North American science-language standard for digital geologic-map databases; Appendix C1 – Sedimentary materials: Science language for their classification, description, and interpretation in digital geologic-map databases; Version 1.0 (12/18/2004), in Soller, D.R., ed., Digital Mapping Techniques ’04—Workshop Proceedings: U.S. Geological Survey Open-File Report 2004-1451, 595 p. Appendix C1 accessed at http://pubs.usgs.gov/of/2004/1451/sltt/appendixC/appendixC_pdf.zip.
Stanford, L.R. and MacKubbin, V.T., 2000, Application of a Digital Geologic Map Data Model in ArcView GIS, in Soller, D.R., ed., Digital Mapping Techniques ’00—Workshop Proceedings: U.S. Geological Survey Open-File Report 00-325, p. 55-56.