USGS

Digital Mapping Techniques '99 -- Workshop Proceedings
U.S. Geological Survey Open-File Report 99-386

Geologic Resources Inventory for the National Park System: Status, Applications, and Geology-GIS Data Model

By Joe Gregson, Anne Poole, Steve Fryer, Bruce Heise, Tim Connors, and Kay Dudek

National Park Service
1201 Oak Ridge Drive, Suite 350
Fort Collins, CO 80525
Telephone: (970) 225-3559
Fax: (970) 225-3585
e-mail: Joe_Gregson@nps.gov
apoole@co.blm.gov
Steve_Fryer@nps.gov
Bruce_Heise@nps.gov
Tim_Connors@nps.gov
Kay_Dudek@nps.gov

SUMMARY

Over the past year, the National Park Service (NPS) has initiated a geologic resources inventory (GRI) to document and evaluate the geology of about 265 national park (N.P.), national monument (N.M.), national recreational area (N.R.A.), national historic site (N.H.S.), and other units of the National Park System (Gregson, 1998). Geologic resource workshops were held for park units in Colorado, and new user-friendly GIS tools were developed for a pilot digital geologic map project at Black Canyon of the Gunnison National Monument (BLCA) and Curecanti National Recreation Area (CURE). The NPS-developed cross section and legend text display tools are an integral part of a standard geology-GIS model that is in development. The evolving geology-GIS model is based on the Washington State Arc/Info GIS data model (Harris, 1998) that is being adapted for ArcView GIS and extended to include components of the AASG/USGS Draft Digital Geologic Map Data Model (GMDM) (Johnson, Brodaric, and Raines, 1998). Cooperative projects for NPS units in Colorado, Craters of the Moon National Monument, and City of Rocks National Reserve are planned or in work, and scoping workshops are scheduled for park units in Utah during 1999.

INTRODUCTION

Bedrock and surficial geologic maps and information provide the foundation for studies of groundwater, geomorphology, soils, and environmental hazards. Geologic maps describe the underlying physical habitat of many natural systems and are an integral component of the geophysical inventories stipulated by the National Park Service (NPS) in its Natural Resources Inventory and Monitoring Guideline (NPS-75) and the 1997 NPS Strategic Plan. The NPS Geologic Resources Inventory (GRI) is a cooperative endeavor among the NPS Geologic Resources Division (GRD), NPS Inventory and Monitoring (I&M) Program (Natural Resource Information Division - NRID), U.S. Geological Survey (USGS), and individual state geological surveys to implement a systematic, comprehensive inventory of the geologic resources for NPS units. The NPS Geologic Resources Inventory for the 265 selected park units consists of four main phases:

  1. a bibliography (GeoBib) of geologic literature and maps,

  2. an evaluation of park geologic maps, resources, and issues,

  3. the acquisition and production of digital map products and information, and

  4. a report with basic geologic information, hazards and issues, and existing data and studies.

STATUS OF GEOLOGIC RESOURCES INVENTORIES

The NPS GRD and I&M Program sponsored a Baseline Geologic Data Workshop in Denver in the fall of 1997 to get input from NPS, USGS, state survey personnel, and cooperators about basic geologic data needs that could be provided by the I&M Program. At the Denver meeting, Colorado, Utah, and North Carolina were chosen as pilot project states to maximize cooperation among the agencies. The group discussed and adopted the four main inventory phases which are reviewed briefly below.

The GeoBib project is completing the initial phase of data collection for existing geologic resources (maps and literature) in each NPS unit and publishing the data on the Internet (URL: http://165.83.36.151/biblios/geobib.nsf/ LOGIN: geobib read PASSWORD: anybody). In addition, index maps showing the location of associated geologic maps have been prepared for the parks in Colorado and Utah. In general, after map coverage for each park is determined, map products can be evaluated, and if needed, additional mapping projects identified and initiated.

Pilot geologic issues/map scoping workshops (with attendees referred to as Park Teams) were organized in 1998 to evaluate the resources in Colorado parks and will continue with projects in Utah during 1999. Park Teams evaluate existing maps for existing and potential digital products and identify any new geologic mapping needs. New geologic mapping projects may be initiated on a case-by-case basis after careful evaluation of park needs, costs, potential cooperators, and funding sources.

GRI cooperators are also assisting with geology-GIS standards to ensure uniform data quantity and quality for digital geologic maps. In addition to standardized data definitions and structure, NPS resource managers also need user-friendly GIS applications that allow the digital geologic map products to "look and feel" like the original published maps. Ongoing pilot digitization projects are providing additional experience and test beds for the geology-GIS model.

Park workshops suggest several applications for park resource management from an enhanced understanding of the parks' geology. Examples include the use of geologic data to construct fire histories, to identify habitat for rare and endangered plant species, to identify areas with cultural and paleontological resource potential, and to locate potential hazards for park roads, facilities, and visitors. Digital geologic maps will enhance the ability to develop precise hazard and resource models in conjunction with other digital data.

After completion of map inventories, a geologic report summarizing USGS, state, academic, and NPS geological literature and data will complete the project for each of the 265 park units. The geologic report content, format, and database are still being developed.

Geologic Mapping and Digitizing Projects

The NPS I&M Program has cost-shared new geologic field mapping for Zion National Park with the State of Utah. Additional field mapping projects have been proposed for 1999 to complete the geologic maps for Bent's Old Fort N.H.S., Curecanti N.R.A., Mesa Verde N.P., and Yucca House N.M. A pilot project to digitize 4 USGS geologic maps for Craters of the Moon N.M. has been completed, and the digitizing of Black Canyon N.M. and Curecanti N.R.A. geologic maps is in progress. Mesa Verde N.P. has completed a digitizing proposal, and preliminary plans are to initiate digitizing projects in 1999 for all Colorado parks with completed geologic maps.

The NPS Geologic Resources Inventory is being actively developed with the cooperation of USGS and state geological surveys. However, many opportunities for project collaboration exist that have not yet been identified, and effective communication among cooperators is a key factor for success of the inventory. Another challenge of inventory planning is the development of digital map standards that are adaptable to diverse geological conditions but still provide quality, uniform products and firm guidance for map developers. Indeed, the diversity of geologic resources found in the National Park System will provide a continuing challenge for effective project management. The National Park Service has identified GIS and digital cartographic products as fundamental resource management tools, and the I&M Program and Geological Resources Division are developing an efficient inventory program to expedite the acquisition of digital geologic information for NPS units throughout the country.

GIS ISSUES AND IMPLEMENTATION - MAKING GEOLOGY USER FRIENDLY

One of the unresolved issues facing developers of digital geologic maps and geology-GIS models is how to include unit descriptions, explanatory text, references, notes, cross sections, and the variety of other printed information that occur on published maps. This issue is particularly important to the National Park Service because there are few geologists employed at parks, and resource managers rarely have the GIS and geologic expertise needed to develop a useful product from digital layers of polygons, lines, points, and associated tabular data. The overarching development goal of the NPS I&M 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.

Since NPS resource managers use GIS as a tool in a wide array of collateral duties, the I&M Program is developing most digital products in ArcView GIS. ArcView interfaces effectively with other software running on the MS Windows operating system, and a new approach using the Windows help software, a MS Visual Basic graphics viewer program, the ArcView legend editor, and the Avenue script language has been developed to automate the display and query of published map information in the GIS.

GIS Map Unit Legend

In ArcView, a theme legend can be edited by selecting (i.e., double-clicking with the mouse) it in the legend. Once in the legend editor, the Legend Type: is set to "Unique Values," and the Values Field: is set to the G_AGE_NO field. The G_AGE_NO field is a numeric field used to sort the map units by geologic time and is equivalent to the GUNIT.AGE.NO field in the GUNIT.MAIN data file of the Washington State data model (WSM) (Harris, 1998) and the class_seq field in the AASG/USGS Digital Geologic Map Data Model (GMDM) (Johnson, Brodaric, and Raines, 1998). In the NPS ArcView model, this field has been replicated in the GUNIT.DBF table to facilitate automating the legend and renamed to G_AGE_NO to accommodate the dBase IV field name limitation of 10 characters. Once the Legend Type: and Values Field: are set, the individual Symbols are edited to match the published map colors, the geologic map symbol, and the unit name. After the legend is complete, it is saved to an ArcView legend file (.avl extension). In general, the 8.3 file naming convention is used to facilitate file sharing across all platforms.

Automating Map Unit Descriptions and Other Textual Information

In most GIS applications, the spatial database structure does not facilitate the use of voluminous textual data. For example, in ArcView, the database text fields only accommodate 254 characters (320 for INFO tables) which limits the ability to include lengthy map descriptions with the spatial data. Several options are available in ArcView to overcome this limitation including concatenating database fields, independent text files, linking to other database system files, and linking to a MS Windows help file. After testing several options, NPS developers have been implementing the Windows help system.

The Windows help system begins with data input or import of all the textual data from the published geologic map(s). In the Black Canyon/Curecanti pilot project, map descriptions, references, notes, and other text were aggregated from eight geologic maps. The table of contents listed all of the map unit symbols and names (equivalent to the class_label and class_desc fields of the AASG/USGS GMDM Classification Object Table) sorted by geologic age. Subsequent pages listed the map unit descriptions with one unit per page (many units had multiple descriptions from different maps) and were paginated by geologic age. At the end, references and notes from each map were entered on separate pages. Help context IDs, topic names, keywords, page numbers, and linking codes were added to the pages which were saved as a rich text format (.rtf) file. Then, the rich text file was compiled into a Windows help file.

Once compiled, the Windows help file can be opened and used with almost any MS Windows software. The table of contents has each map unit symbol and unit name "hot-linked" to the descriptions, and each description is hot-linked to the references and notes. Using the built-in Windows help tools, users can jump instantly to the table of contents, page through the age-sorted unit descriptions, search for keywords, or index the file and perform full-text searches of the entire file. The Black Canyon/Curecanti pilot project help file consists of more than 50 printed pages of information for more than 130 map units. Advantages of the Windows help file are that most text formatting, such as font, size, color, etc., are preserved in the final product, many graphics and tables are also supported, and the help system can be developed somewhat independently of the digital geologic map.

In ArcView GIS, three Avenue scripts were written to function with a toolbar button to automate the Windows help file and call unit descriptions interactively from the geologic map. The button tool is only active when the geology theme is turned on. The user selects the map unit help tool from the ArcView toolbar and clicks on the desired map unit to view the associated unit description. Using the map unit symbol (GUNIT_SYM) and the corresponding help context ID, the Avenue routine loads the Windows help file and pages to the map unit description. Thus, the map unit descriptions and other text are instantly available to the user of the digital map.

Automating the Geologic Cross Sections

Geologic cross sections are integral components of many published geologic maps and provide important spatial visualization tools to assist users with understanding the mapped geology. The I&M Program has developed a simple interactive system for displaying cross sections using ArcView and a MS Visual Basic (VB) graphics viewer program. The cross sections are scanned digital graphics files that ArcView can load and display via system calls to the VB graphics viewer program. This allows the user to interactively select the cross section(s) to view. With projects such as the Black Canyon/Curecanti pilot, the ability to quickly view some 28 cross sections throughout the area is a powerful asset toward understanding the area's geology.

To prepare the cross sections for viewing, the graphics are first scanned at 100 dots-per-inch (DPI) and saved as a digital JPEG (.jpg extension) graphics file. The JPEG format was chosen to allow the graphics to be served and viewed over the Internet in the future. Once again, the 8.3 file naming convention is used to facilitate sharing across all platforms, and file names are based on the map series designation and the designated cross section on the map (e.g., GQ1516AA.JPG is the A-A' cross section on the Geologic Quadrangle Map GQ-1516).

Although ArcView and the Avenue language provide several ways to display graphics and images, ArcView's capabilities are inadequate for efficient viewing of cross sections that could be up to 6" x 48" in size. Therefore, a simple VB graphics viewer program was developed to provide this capability. The viewer displays the graphics at 100% with the ability to scroll from one end of the section to the other.

To automate the graphics display, the cross section lines were digitized into an ArcView shape file (e.g., blcagsec.shp and associated extensions). Two text fields were added to the shape file table (e.g., blcagsec.dbf): GSEC_ID, which contains the section line (e.g., A-A'), and GSEC_FILE, which contains the complete path and filename of the cross section graphics file.

In ArcView GIS, three Avenue scripts were written to function with a toolbar button to automate the cross sections and call graphics files interactively from the geologic map. The button tool is only active when the cross section theme is turned on. The user selects the cross section viewer tool from the ArcView toolbar and clicks on the desired cross section line displayed on the map. Using the cross section line and the corresponding filename, the Avenue script loads the graphics viewer and displays the selected section. Thus, the cross sections are interactively available to the user of the digital map.

Figure 1 Figure 1. Simplified relationships among the database tables discussed and outlined in the text. Bold type denotes database file names for Arc/Info (top) and ArcView (below). The tabular relationships are coded with "m" for many and "1" for one. Related field names are in italics.

The models display areas with potentially high vulnerability to destructive processes (Figure 2), particularly if the land is disturbed (such as by wildfire, road building, and drainage diversion). Simple GIS overlays of these maps provide guides to making land-use decisions, such as routing a road. The models are created using Arc/Info's GRID module, which performs raster-based analysis. Results of the models can be viewed as images within ArcView, or converted into a vector format to allow the model results to be queried. The models can be improved by collecting better quality information on soils, more detailed slope maps, and better precipitation data.

DRAFT NPS GEOLOGY-GIS DATA MODEL

As discussed above, a standard NPS geology-GIS data model is being developed based on new user-friendly ArcView GIS tools and adapted from the Washington State Arc/Info geology data model (WSM) (Harris, 1998). The NPS model will be further developed over the next year to include additional components of the USGS Draft Digital Geologic Map Data Model (GMDM) (Johnson, Brodaric, and Raines, 1998). Although the model is currently structured for Arc/Info and many details still need to be worked out, one important adaptation is to standardize the database field names to 10 characters or less that will port seamlessly among Arc/Info, ArcView, and other software compatible with the Dbase IV format. Arc/Info coverage and table names have been shortened to 7 characters to accommodate renaming the file name stem for look-up tables (e.g., CODEUNT.INF to CODEUNT1.DBF) when the stem has already been used for the spatial attributes (e.g., CODEUNT.PAT to CODEUNT.DBF). Files and field names that have been added or changed from the Washington State model (Harris, 1998) are marked with an asterisk (*). The new NPS model's data themes are listed below followed by a selected data dictionary for the five themes that have been partially adapted to date (Table 1). Although much work remains, final development of the NPS geology-GIS data model should be completed within the next year.

Table 1. Coverages/Shape Files (modified from Harris, 1998)
Present work is focusing on renaming files to consistently use the 8.3 file name convention with the NPS park unit alpha code (CODE) and to limit field names to 10 characters or less.  
*CODEGLG poly Map units or main geologic spatial data containing both polygon data describing the map units and linear data describing the interface between those units (WSM GUNIT).
*CODEGLN line Map units or main geological spatial data represented as lines due to map scale limitations (WSM GUNITLN).
*CODEGPT point Map units or main geological spatial data represented as points due to map scale limitations (WSM GUNITPT).
*CODEFLT line Faults and their descriptions (WSM GFAULT).
*CODEFLD line Linear fold axes and their descriptions (WSM GFOLD).
*CODESEC line Cross section lines and their attributes (no WSM equivalent).
*CODEATD point Attitude observation points and their attributes (WSM GATTUD).
*CODEDAT point Age-date sample location points (fossil or radiometric age estimates) (WSM GDTSMPL).
*CODEVNT point Volcanic vents, eruptive centers, and lithologic descriptions (WSM GVENT).
*CODEDIK line Individual lithologic dikes and lithologic descriptions (WSM GDIKE).
*CODEDKS poly Areas of lithologic dikes too numerous to map as individual segments (WSM GDIKESWARM).
Coverages/Shape Files Data Dictionary
*CODEGLG (network coverage containing both arc (.AAT) and polygon (.PAT) attribution)

DATA FILE NAME: CODEGLG.PAT or CODEGLG.DBF

ITEM NAME WID-TYP DESCRIPTION
AREA 4 - F  
PERIMETER 4 - F  
*GUNIT_ 4 - B (WSM GUNIT#; automatically converted in shape file .dbf)
*GUNIT_ID 4 - B (WSM GUNIT-ID; automatically converted in shape file .dbf)
*GUNIT_IDX 6 - I unique number for each polygon (WSM GUNIT.ID)
*GUNIT_SYM 12 - C age-lithology unit symbol (WSM GUNIT.LABEL.CD)
*USGS_SYM 12 - C geologic symbol from USGS geologic map(s)
*G_AGE_NO 4 - F number to age-sort map units (from *CODEGLG.INF table)
*GMAP_ID 4 - I code for *CODEMAP.INF look-up table (WSM GMAP.ID)


*GUNIT_SYM (map unit symbol in ASCII text; WSM GUNIT.LABEL.CD, GMDM class_label)
Age-lithology unit polygon labels. Item is also the key used to relate the *CODEGLG coverage with the *CODEGLG.INF or CODEGLG1.DBF (WSM GUNIT.MAIN) file that contains additional geologic attributes for the polygons.

*GMAP_ID (geologic map source information)
Unique integer value that relates to series and citation information of the published map in the *CODEMAP.INF or CODEMAP.DBF file.

DATA FILE NAME: CODEGLG.AAT

ITEM NAME WID-TYP DESCRIPTION
*FNODE_ 4 - B (WSM FNODE#; automatically converted in shape file .dbf)
*TNODE_ 4 - B (WSM TNODE#; automatically converted in shape file .dbf)
*LPOLY_ 4 - B (WSM LPOLY#; automatically converted in shape file .dbf)
*RPOLY_ 4 - B (WSM RPOLY#; automatically converted in shape file .dbf)
LENGTH 4 - F  
*GUNIT_ 4 - B (WSM GUNIT#; automatically converted in shape file .dbf)
*GUNIT_ID 4 - B (WSM GUNIT-ID; automatically converted in shape file .dbf)
*GCNTCT_IDX 7 - I unique number for each arc segment (WSM GCNTCT.ID)
*GCNTCT_TYP 1 - I code for types of polygon boundaries (contacts) (WSM GCNTCT.TYPE.CD)
FLTCNT 1 - C flags lithologic contacts that are also faults
*GMAP_ID 4 - I code for *CODEMAP.INF look-up table (WSM GMAP.ID)
*GCNTCT_TYP (polygon boundary/geologic contact type code)
1 known location
2 concealed location
3 scratch boundary
4 gradational boundary
5 shoreline
6 approximate location
7 quadrangle boundary
8 ice boundary
9 inferred location

FLTCNT (fault contact)

Y Yes, the fault is also a lithologic contact
N No, the fault is not a lithologic contact

*CODEFLT (arc or line coverage)

DATA FILE NAME: CODEFLT.AAT or CODEFLT.DBF

ITEM NAME WID-TYP DESCRIPTION
*FNODE_ 4 - B (WSM FNODE#; automatically converted in shape file .dbf)
*TNODE_ 4 - B (WSM TNODE#; automatically converted in shape file .dbf)
*LPOLY_ 4 - B (WSM LPOLY#; automatically converted in shape file .dbf)
*RPOLY_ 4 - B (WSM RPOLY#; automatically converted in shape file .dbf)
LENGTH 4 - F  
*GFAULT_ 4 - B (WSM GFAULT#; automatically converted in shape file .dbf)
*GFAULT_ID 4 - B (WSM GFAULT-ID; auto-converted in shape file .dbf)
*GFAULT_IDX 5 - I unique ID number for each fault (WSM GFAULT.ID)
*GFLT_SEG_N 4 - I unique number for each fault segment (GFLTSEG.NO)
*GFLT_SEG_T 3 - I code value used to differentiate fault types and characteristics of the fault at the segment level (GFLTSEG.TYPE.CD)
FLTCNT 1 - C flags faults that are also lithologic contacts
*GMAP_ID 4 - I code for *CODEMAP.INF look-up table (WSM GMAP.ID)
*GFAULT_IDX (geologic fault ID)
A geologic fault is commonly segmented as a result of intersecting different polygons. This item identifies an individual fault regardless of the number of segments. This item is also a key used to relate the *CODEFLT coverage with the *CODEFLT.INF file that contains fault names and data.

GFLT_SEG_T (geologic fault segment type code)

1 fault, unknown offset
2 fault, unknown offset, approximate location
3 fault, unknown offset, concealed
4 fault, unknown offset, queried
5 fault, unknown offset, approximate location, queried
6 fault, unknown offset, concealed, queried
7 And so on for 83 entries.

FLTCNT (fault contact)

Y Yes, the fault is also a lithologic contact
N No, the fault is not a lithologic contact

*CODEFLD (arc or line coverage)

DATA FILE NAME: CODEFLD.AAT or CODEFLD.DBF

ITEM NAME WID-TYP DESCRIPTION
*FNODE_ 4 - B (WSM FNODE#; automatically converted in shape file .dbf)
*TNODE_ 4 - B (WSM TNODE#; automatically converted in shape file .dbf)
*LPOLY_ 4 - B (WSM LPOLY#; automatically converted in shape file .dbf)
*RPOLY_ 4 - B (WSM RPOLY#; automatically converted in shape file .dbf)
LENGTH 4 - F  
*GFOLD_ 4 - B (WSM GFOLD#; automatically converted in shape file .dbf)
*GFOLD_ID 4 - B (WSM GFOLD-ID; auto-converted in shape file .dbf)
*GFOLD_IDX 6 - I unique ID number for each fold (WSM GFOLDT.ID)
*GFLD_SEG_N 3 - I unique number for each fold segment (GFOLDSEG.NO)
*GFLD_SEG_T 2 - I code value used to differentiate fold types and characteristics of the fold at the segment level (GFOLDSEG.TYPE.CD)
*GMAP_ID 4 - I code for *CODEMAP.INF look-up table (WSM GMAP.ID)
*GFOLD_IDX (geologic fold ID)
A geologic fold is commonly segmented as a result of intersecting different polygons. This item identifies an individual fold regardless of the number of segments. This item is also a key used to relate the *CODEFLD coverage with the *CODEFLD.INF file that contains fold names and data.

GFLD_SEG_T (geologic fold segment type code)

1 anticline
2 anticline, approximate location
3 anticline, concealed
4 anticline, queried
5 anticline, approximate location, queried
6 anticline, concealed, queried
7 And so on for 42 entries.

*CODEATD (point coverage or shape file)

DATA FILE NAME: CODEATD.PAT or CODEATD.DBF

ITEM NAME WID-TYP DESCRIPTION
AREA 4 - F  
PERIMETER 4 - F  
*GATTUD_ 4 - B (WSM GATTUD#; auto-converted in shape file .dbf)
*GATTUD_ID 4 - B (WSM GATTUD-ID; auto-converted in shape file .dbf)
*GATTUD_IDX 5 - I unique number for each point (WSM GATTUD.ID)
*GATTUD_CD 2 - I code for type of attitude measurement (WSM GATTUD.CD)
*GATTUD_ST 3 - I azimuth of strike or trend (0-360 degrees clockwise from the north with dip direction clockwise from strike direction)
*GATTUD_DP 2 - I dip or plunge degrees from horizontal (GATTUD.DIP.ANG)
*GMAP_ID 4 - I code for *CODEMAP.INF look-up table (WSM GMAP.ID)
*GATTUD_CD (observation code for structural attitude point)
1 strike and dip of beds
2 strike and dip of overturned beds
3 strike of vertical beds
4 strike and dip of beds, dip unspecified
5 approximate strike and dip of beds
6 horizontal beds
7 strike an dip of foliation
8 And so on for 24+ more entries.

*CODEDAT (point coverage or shape file)

DATA FILE NAME: CODEDAT.PAT or CODEDAT.DBF

ITEM NAME WID-TYP DESCRIPTION
AREA 4 - F  
PERIMETER 4 - F  
*GDTSM_ 4 - B (WSM GDTSMPL#; auto-converted in shape file .dbf)
*GDTSM_ID 4 - B (WSM GDTSMPL-ID; auto-converted in shape file .dbf)
*GDTSM_CD 2 - I code for age-dating technique (WSM GDTSMPL.METH.CD)
*GDTSM_NO 3 - I unique code for each age sample location (GDTSMPL.NO)
*GDTSM_AGE 80 - C relative or absolute age of rock sample (WSM AGE)
*GDTSM_REM 254 - C notes about a specific age-date sample (WSM REMARKS)
*GUNIT_SYM 12 - C age-lithology unit symbol (WSM GUNIT.LABEL.CD)
*GMAP_ID 4 - I code for *CODEMAP.INF look-up table (WSM GMAP.ID)
*GDTSM_CD (geologic sample age-dating methodology code)
1 radiometric
2 paleontologic

*GDTSM_NO (geologic data sample number)
This item contains the sample number from the original source map. The number is used to reference additional explanatory text found on the map.

*GUNIT_SYM (map unit symbol in ASCII text)
Age-lithology unit polygon labels. Item is also the key used to relate the *CODEGLG coverage with the *CODEGLG.INF file that contains additional geologic attributes for the polygon.

*GDTSM_AGE (age of rock sample)
The age of the rock sampled expressed as a relative geologic age, such as Jurassic, or an absolute age, such as 5,000,000 years before present.

*GDTSM_REM (remarks)
Notes about the sample, such as the specific technique(s) used to determine the age of the sample.

Other Coverages/Shape Files

The other coverage/shape files listed above have not yet been evaluated or adapted for the NPS geology-GIS data model, but the renaming of files and data fields will follow a similar pattern.
Accessory Data Files

*CODEGLG.INF (look-up data file, WSM GUNIT.MAIN)
DATA FILE NAME: *CODEGLG.INF or *CODEGLG1.DBF

ITEM NAME WID-TYP DESCRIPTION
*GUNIT_SYM 12 - C age-lithology unit symbol (WSM GUNIT.LABEL.CD)
*GUNIT_NAME 100 - C formal name of map unit, if any
*G_REL_AGE 5 - C relative age code (WSM GUNIT.REL.AGE.CD)
*G_SSCR_TXT 6 - C subscript from the map symbol (WSM GUNIT.SSCRPT.TXT)
*G_AGE_NO 5 - N number to age-sort map units (WSM GUNIT.AGE.NO)
*G_AGE_TXT 50 - C geologic time period of map unit (WSM GUNIT.AGE.TXT)
*G_MJ_LITH 3 - C 3 char. major lithology code (WSM GUNIT.MJ.LITH.CD)
*G_LITH_NO 4 - B code used to sort on lithology (WSM GUNIT.LITH.NO)
*G_LITH_CD 10 - I code used to describe lithology (WSM GUNIT.LITH.CD)
*G_LITH_TXT 100 - C brief text describing lithology (WSM GUNIT.LITH.TXT)
*G_NOTE_TXT 254 - C descriptive notes about the map unit (GUNIT.NOTE.TXT)
*GMAP_SRC 100 - C GMAP_IDs of map source(s), if any (similar to GMDM source_id)
*G_MJ_LITH (map unit major lithology code)
EXT extrusive igneous
INT intrusive igneous
MET metamorphic
SED sedimentary
VAS volcanic and sedimentary
UNC unconsolidated

Example record from *CODEGLG.INF or *CODEGLG1.DBF (modified from Harris, 1998)

GUNIT_SYM = Qvba(pc)
GUNIT_NAME = Basaltic Andesite of Puny Creek
G_REL_AGE = Q
G_SSCR_TXT = vba
G_AGE_NO = 1.00
G_AGE_TXT = Holocene
G_MJ_LITH = EXT
G_LITH_NO = 39.10
G_LITH_CD = vba
G_LITH_TXT = basaltic andesite flows
G_NOTE_TXT = volcanic lava flows with interbedded soil horizons
GMAP_SRC = I-757; GQ-1082

*CODEMAP.INF (WSM GMAP and GMAP.TXT INFO look-up data files combined/modified with Map and Source tables from AASG/USGS GMDM)

DATA FILE NAME: *CODEMAP.INF or *CODEMAP.DBF

ITEM NAME WID-TYP DESCRIPTION
*GMAP_ID 4 - I code for relating this table (WSM GMAP.ID, GMDM map_id)
*GMAP_YEAR 4 - I compilation or publication year (WSM GMAP.COMPILE.YR)
*GMAP_AUTH 254 - C map author(s) (WSM GMAP.AUTHOR.YR; GMDM map_author)
*GMAP_ORG 100 - C organization that created or compiled the map (GMDM org_id)
*GMAP_TITLE 100 - C complete map title (WSM GMAP.REF.TXT; GMDM map_title)
*GMAP_SERIES 20 - C map series or organizational identifier (e.g., USGS GQ-1516)
*GMAP_SCALE 7 - I source map scale denominator (WSM GMAP.SCL)
*GMAP_PROJ 100 - C name or description of map projection (GMDM map_projection)
*GMAP_REF 254 - C complete map citation in USGS style
*GMAP_DESC 254 - C brief description of the map (GMDM map_desc)
*GMAP_XMAX 7 - I eastern limit of map in decimal degrees (GMDM map_xmax)
*GMAP_XMIN 7 - I western limit of map in decimal degrees (GMDM map_xmin)
*GMAP_YMAX 7 - I northern limit of map in decimal degrees (GMDM map_ymax)
*GMAP_YMIN 7 - I southern limit of map in decimal degrees (GMDM map_ymin)
*GMAP_SRC 100 - C GMAP_IDs of map source(s), if any (similar to GMDM source_id)
*CODEFLT.INF (look-up data file)

DATA FILE NAME: CODEFLT.INF or CODEFLT1.DBF

ITEM NAME WID-TYP DESCRIPTION
*GFAULT_IDX 5 - I unique ID number from *CODEFLT (WSM GFAULT.ID)
*GFAULT_NM 60 - C fault name, if any (WSM GFAULT.NM)
*GMAP_ID 4 - I code for *CODEMAP.INF look-up table (WSM GMAP.ID)
*CODEFLD.INF (look-up data file)

DATA FILE NAME: CODEFLD.INF or CODEFLD1.DBF

ITEM NAME WID-TYP DESCRIPTION
*GFOLD_IDX 5 - I unique ID number from *CODEFLD (WSM GFOLD.ID)
*GFOLD_NM 60 - C fold name, if any (WSM GFOLD.NM)
*GMAP_ID 4 - I code for *CODEMAP.INF look-up table (WSM GMAP.ID)

REFERENCES

Gregson, Joe D., 1998, Geologic Resources Inventory--Geologic Resources Division, Inventory and Monitoring Program, in David R. Soller, ed., Digital Mapping Techniques '98--Workshop Proceedings: U.S. Geological Survey Open-File Report OFR 98-487, p. 109-111, https://pubs.usgs.gov/openfile/of98-487/gregson.html.

Harris, Carl F.T., 1998, Washington State's 1:100,000-Scale Geologic Map Database: An Arc/Info Data Model Example, in David R. Soller, ed., Digital Mapping Techniques '98--Workshop Proceedings: U.S. Geological Survey Open-File Report OFR 98-487, p. 27-35, https://pubs.usgs.gov/openfile/of98-487/harris.html.

Johnson, Bruce R., Boyan Brodaric, and Gary L. Raines, 1998, Draft Digital Geologic Map Data Model, Version 4.2: Association of American State Geologists/U.S. Geological Survey Geologic Map Data Model Working Group Report, May 19, 1998, http://ncgmp.usgs.gov/ngmdbproject/.

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