GRI Digital Geologic Maps

Geologic Resources Inventory Digital Map Products for Grand Canyon National Park (GRCA)

At the GRI scoping meeting for Grand Canyon National Park (GRCA) in 2001, completed, on-going and planned 30’ x 60’ 1:24,000 scale mapping by George Billingsley (U.S. Geological Survey) and others was identified as the best large-scale geologic map data for the park.  Upon acquisition of eight 30’ x 60’ digital GIS datasets from the U.S. Geological Survey in 2012 and 2013 the GRI converted the data to an ESRI 10.1 file geodatabase using the NPS GRI Geology-GIS Geodatabase Data Model (O’Meara et al., 2014), which specifies standards for attribution and spatial relationships, incorporating topological rules, subtypes, domains, and relationship classes.  The eight 30’ x 60’ digital maps were then compiled into a single digital geologic-GIS map of the entire park and adjacent area.

A goal in converting the U.S. Geological Survey digital data and published maps for GRCA was to maintain all aspects of the original (source) maps while enhancing usability by providing all elements of the maps in a compact digital format that is usable in ESRI ArcGIS software, as well as Google Earth software.  Additional information found on the source maps, such as unit descriptions, correlation of unit figures, cross sections, other figures and source references, was included in the accompanying ancillary map information document, in Adobe Acrobat PDF format.  GIS data layers for the map included attitude measurements, faults, folds, dikes, fractures, geologic units and contacts, volcanic point and linear features, mine features, sinkhole and collapse features, cross sections, and map symbology.  In addition, two GIS tables containing information about the geologic units and source map references were produced.

In addition to the GIS (file geodatabase) data and accompanying 10.1 ArcMap document, as well as the ancillary map information document, the final digital geologic-GIS map product for GRCA also includes 10.1 layer files that present feature symbology for each geologic data layer, robust FGDC- and NPS-compliant metadata, and an introductory GIS readme file.

From the final GRI 10.1 file geodatabase (GIS) product two derivative products were produced, an ESRI 10.1 online map service product, and a Google Earth KML map product.  The ESRI map service product is presently in the production and viewer development stage, however, the Google Earth product is readily available.  The Google Earth KMZ product contains a limited version of the full spatial dataset (limited features and symbology).  The Google Earth KMZ file possesses on-line links to the GRI program and its products, as well as to the readme document (on-line version), FAQ metadata (in .html format), and the GRI ancillary map information document pertaining to the dataset.  Users are, however, encouraged to only use the Google Earth data for basic visualization, and to use the GIS data for any type of data analysis or investigation.  Google Earth software is available for free at:

The GRI digital geologic-GIS (ESRI 10.1 file geodatabase) product (map download zip file) can be obtained by clicking,

The GRI Google Earth (KMZ) product (map download zip file) can be obtained by clicking,

These GRI digital geologic-GIS products for GRCA, including individual 30’ x 60’ digital geologic-GIS maps, can be obtained from the National Park Service (NPS) Data Store GRI GRCA product record,

Users can acquire all available GRI digital geologic-GIS products, as well as reports and scoping reports, at the GRI Publications (“Pubs”) page,