ANNOUNCING GEMS—A STANDARD FORMAT FOR DIGITAL PUBLICATION OF GEOLOGIC MAPS, VERSION 2.0

GeMS (Geologic Map Schema) is a revision of the geologic map database schema described at the GSA annual meeting in 2009 and published in early 2010 as NCGMP09 v1.1. GeMS (or v2) is the schema for digital publication of geologic maps funded by the National Cooperative Geologic Mapping program of the USGS. GeMS is fundamentally a content standard, implemented in ESRI’s ArcGIS, for capturing the content of a traditional paper geologic map. In addition to the geologic map content GeMS adds three additional elements: a glossary of terms, standardized classification of geologic materials, and feature-level metadata.

Revision from v1.1 to v2 was guided by extensive discussion within the Association of American State Geologists-U.S. Geological Survey Digital Mapping Techniques community. GeMS builds on the experience of numerous agencies and individuals, several years of producing maps with NCGMP09 v1.1, and training sessions and discussions that illuminated deficiencies in the v1.1 documentation and desirable changes to the schema.

Most changes from v1.1 to v2 are improvements to the documentation. The few substantive schema changes include: renaming of the GeneralLithology classification to GeoMaterial; deletion of two and addition of eleven GeoMaterial terms; inclusion of the GeoMaterial dictionary table in each map database; minor changes in map-feature tables for consistency; and addition of optional table MiscellaneousMapInformation. With the exception of reclassification of some geologic materials necessitated by deletion and addition of terms, migration of databases from v1.1 to v2 could be automated.

As of August 2017, GeMS is in the final stages of revision after peer review. We expect it to be released as a USGS report later in 2017, along with script tools that create empty databases, facilitate the construction of database content, check map database topology, and validate conformance to the GeMS schema. The next steps are outreach and training in the use of the GeMS, and formal proposal of GeMS to the Federal Geographic Data Committee as the standard schema for geologic map databases.