Bedrock and surficial geologic maps and supporting information provide the foundation for studies of ecosystems, earth history, groundwater, geomorphology, soils, and environmental hazards such as fire history, landslide and rockfall potential, etc. Geologic maps describe the underlying physical conditions of many natural systems and are an integral component of the physical science inventories stipulated by the National Park Service (NPS) in its Natural Resources Inventory and Monitoring Guideline. The NPS has identified GIS and digital cartographic products as fundamental resource management tools. There are few geologists employed at parks, thus these tools are particularly important to the National Park Service to aid resource managers in using geologic data for park management decisions. At Capitol Reef National Park in Utah, resource manager Tom Clark has found numerous uses of digital geologic maps for predicting habitat for threatened and endangered species
Digital geologic maps have several advantages over paper geologic maps. Digital geologic maps can be used in a digital GIS environment where they can be integrated with other geospatial (soils, vegetation, hydrology, etc.) data to provide analysis of spatial relationships. A digital GIS provides quick, reproducible, precise analysis results. Digital data are also more easily shared and transferred between users. With digital attribute capability a digital geologic map becomes a powerful database!
The Odyssey from paper to digital
One of the unresolved issues facing developers of digital geologic maps models is how to include map unit descriptions, supplemental explanatory text (references and map notes), geologic cross sections, and the variety of other printed information that occur on published maps. The overarching development goal of the NPS Inventory and Monitoring program is to produce digital products that are immediately useful to anyone familiar with their analog counterparts. For geologic maps, this means that the map unit legend must be sorted and shaded appropriately by geologic age and that all textual, graphical, and other information from the published maps must be available interactively to the user. In short, the digital product must "look and feel" like its published source.
The NPS is developing most digital products in ESRI (Environmental Systems Research Institute) ArcView GIS. ArcView interfaces effectively with other software running on the Microsoft Windows operating system. Also, integrating a variety of tools including the NPS GIS Theme Manager, Windows Help software, a Microsoft Visual Basic graphics viewer program, and the ArcView legend editor has allowed users to display geologic map information in a digital GIS.
Completing the Odyssey
This article details the steps entailed in transforming a paper geologic map to a user-friendly digital geologic map and database. In short the paper geologic map is scanned and the resulting image is georeferenced, providing a background for the digitization (capture) of geologic features. In accordance with the NPS Geology-GIS Data Model, the spatial and geologic feature types present (i.e. polygon, line, point and fault, fold, unit, etc.) are captured into appropriate GIS coverages and attributed as per the Data Model. These data are then incorporated into the NPS GIS Theme Manager that facilitates (in ArcView 3.2) the presentation of the various map coverages along with any FGDC metadata and accompanying help files that display map notes, unit descriptions and other ancillary data from the original paper source map. Any map graphics (e.g. geologic cross sections) are scanned from the original paper map and hotlinked to a coverage (e.g. in this case the cross section line coverage) on the digital geologic map. These data are then posted on the NPS I&M GIS Clearinghouse website for user access and download.
Geologists use two types of maps to convey various geologic features: bedrock and surficial geologic maps.
Bedrock geologic maps aid in the following:
• Conveys information about the geologic history, including the origin of features and the processes that created them
• Used to identify scope and type of geologic hazards (rockfall, faulting, flooding, etc.)
• Used to identify location and type of resources (coal, ore deposits, ground-water, oil & gas, etc.)
• Provides basis for sound land use planning (hazards, engineering considerations, etc.)
Surficial geologic maps:
• Convey information about recent geologic processes and resultant features
• Are key to understanding surface hydrology, near-surface groundwater, & watershed response
• Can be used to understand patterns of soil development and infer occurrences of flora, fauna, fire prone areas, archeological sites, etc. (other resources of concern)
• Be used to identify erosional susceptibility
USING DIGITAL GEOLOGY AT CAPITOL REEF NATIONAL PARK
NPS resource management professionals are beginning to see the importance of using digital datasets to respond to issues in parks. Geology, often scoffed at as merely being attributable only to the “scenery”, plays a much more diverse role in the total ecosystem than it is usually given credit for. The importance of geology to our everyday activities is obvious to the geologist: it ranges from shaping the earth’s surface (the actual topographic expression of a landform) to direct relationships with soil development from “parent material” to the species of plants and animals that grow on the land, to controlling where humans eventually settle in communities. With GIS, now the geologist can illustrate the importance of the science of geology to other natural resource enthusiasts, such as soil scientists, botanists vegetation specialists, and ecologists.
Therefore, through integrated efforts a few important uses of geology and geologic maps have found some interesting correlations to other natural resource disciplines. Here are a few quick examples:
At Capitol Reef, Tom Clark (Chief of Natural Resources) has been using the parks digital geology layer, along with soils and aspect data to predict habitats for species listed as threatened or endangered. He has found direct connections with geologic substrate and successful habitat prediction of three known endangered species.
• Habitat for Winkler’s cactus seems to be confined to geologic outcrops and expressions of the Jurassic Morrison Formation’s Salt Wash Member within Capitol Reef NP. To the south of the park there is a correlation with the Cretaceous Dakota Formation, and to the north of the park it is found in the Curtis Formation
• Barneby reed-mustard is confined to north-facing, cliff exposures in the Triassic Moenkopi Formation and likely has additional ties to moisture levels.
• Jones cycladenia is only found in the uppermost member of the Triassic Chinle Formation
Additionally, he has found correlations of species specific only to exposures of the Navajo Sandstone for the following:
• Beck’s Spring Parsley seems to only occur in north facing narrow canyons within the Jurassic Navajo Sandstone
• Harrison’s milkvetch
• Maguire’s daisy
• Rabbit Valley gilia
For a more detailed paper on this matter, please see Park Science (Volume 19, Number 2, December 1999, p. 27-29) The article is attached below for simplicity.
For more information on the NPS Geologic Resources Inventory Program, please see Ranger (Volume XVIII, number 2, Spring 2002, p. 2-4 (http://www.anpr.org/geology.htm) and http://www2.nature.nps.gov/grd/geology/gri .
It is also attached below for simplicity.