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Digital Mapping Techniques '00 -- Workshop Proceedings
U.S. Geological Survey Open-File Report 00-325

The National Park Service Digital Geologic Map Model: Transformation from Paper to Digital, Featuring Legends, Cross Sections, Map Notes and Keyword Searchability

By Steve Fryer1, Joe Gregson1, Tim Connors2, Anne Poole1 and Bruce Heise2

1National Park Service
Natural Resources Information Division
1201 Oak Ridge Drive, Suite 350
Fort Collins, CO 80525
Telephone: (970) 225-3584
Fax: (970) 225-3585
e-mail: Steve_Fryer@nps.gov, Joe_Gregson@nps.gov, Anne_Poole@nps.gov 		  2National Park Service Geologic Resources Division
12795 West Alameda Parkway
P.O. Box 25287
Denver, CO 80225
Telephone: (303) 969-2093
Fax: (303) 987-6792
e-mail: Tim_Connors@nps.gov, Bruce_Heise@nps.gov

SUMMARY

Beginning in 1998, the National Park Service initiated a geologic resources inventory (GRI) to document and evaluate the geologic resources of about 265 National Park System units (national parks, monuments, recreational areas, historic sites, seashores, etc.). GRI workshops were held for units in Colorado (1998), Utah and Idaho (1999), and North Carolina (on-going in 2000). New, user-friendly GIS tools have been developed for digital geologic maps of Black Canyon of the Gunnison National Park, Curecanti National Recreation Area, Rocky Mountain National Park, and Craters of the Moon National Monument. Applications, including the NPS-developed ArcView Data Browser, graphical cross section viewer and legend text display tools are integrated with a standard geology-GIS model that is in development. The evolving geology-GIS model is based on the Washington State ArcInfo GIS data model (Harris 1998) that is being adapted for ArcView GIS and extended to include components of the North American Geologic Map Data Model (NADM), http://geology.usgs.gov/dm/.

INTRODUCTION

Bedrock and surficial geologic maps and supporting 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 physical science 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 to implement a systematic, comprehensive inventory of the geologic resources in NPS units. Cooperators include the NPS Geologic Resources Division, NPS Inventory and Monitoring (I&M ) Program (Natural Resource Information Division), U.S. Geological Survey (USGS), and individual state geological surveys (currently Colorado, Utah, and North Carolina). The GRI for the 265 park units with significant natural resources consists of four main phases:

  1. "GRBib", compilation of a bibliography of geologic literature and maps;
  2. "scoping sessions", an on-site evaluation of park geologic maps, resources, and issues;
  3. digital geologic map products with accompanying supporting information; and
  4. a summary report with basic geologic information on hazards, issues, and existing data and studies.

STATUS OF GEOLOGIC RESOURCES INVENTORIES

The NPS Geologic Resources Division and Inventory and Monitoring Program sponsored a workshop in baseline geologic data in Denver, Colorado in fall 1997 to receive input from the NPS, USGS, state geological survey personnel, and cooperators on needed basic geologic data that Inventory and Monitoring Program could provide. At the meeting, Colorado, Utah, and North Carolina were chosen as pilot project states to maximize cooperation among the agencies and provide consistency in workshop planning. The group discussed and adopted the four main inventory phases that are reviewed briefly below.

Geologic Bibliographies
"GRBib", the bibliography of existing geologic maps and literature for each NPS unit in Colorado, Utah and North Carolina is available on the internet (URL: http://165.83.36.151/biblios/geobib.nsf; LOGIN: "geobib read", PASSWORD: "anybody") and is also prepared as printable documents at http://www2.nature.nps.gov/grd/geology/gri/products/geobib/. Also, geologic index maps showing the location of associated geologic maps and their scale have been prepared for these same parks. In general, after map coverage for each park is determined, map products can be evaluated, and if needed, additional mapping projects identified and initiated.

Park Workshop Meetings
GRI Park Workshops (scoping sessions) were organized in 1998 (Colorado), 1999 (Utah and Idaho), and now in 2000 (North Carolina) to evaluate each park's geologic resources. Park teams have evaluated existing maps for digital products and identified needed geologic mapping. New geologic mapping may be initiated on a case-by-case basis after careful evaluation of needs, costs, potential cooperators, and funding sources.

GRI cooperators are developing geologic-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 paper maps. Pilot digitization projects are providing additional information for the evolving NPS digital map standards.

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.

Upon completion of an inventory in a park, the available geological literature and data from the NPS, USGS, state, and academic institutions will be documented in a summary report. The content, format, and database structure of such reports are still being developed.

Geologic Mapping and Digitizing Projects
The NPS I&M Program has cost-shared new geologic field mapping for Zion NP and Glen Canyon NRA with the Utah Geological Survey. Additional field mapping projects have been initiated or completed for the geologic maps for Bent's Old Fort NHS, Curecanti NRA, Florissant Fossil Beds NM, Great Sand Dunes NM, Capitol Reef NP, Cedar Breaks NM, Golden Spike NHS, and Natural Bridges NM.

Digitization of geologic maps for Arches NP, Black Canyon of the Gunnison NP, Curecanti NRA, Craters of the Moon NM, Rocky Mountain NP, Bent's Old Fort NHS, Natural Bridges NM, and Florissant Fossil Beds NM has been completed.

Preliminary plans are to initiate digitizing projects in 2000 for all Utah parks with completed paper geologic maps (Bryce Canyon NP, Canyonlands NP, Capitol Reef NP, and Timpanogos Cave NM). The NPS Geologic Resources Inventory is being actively developed with the cooperation of USGS and state geological surveys. However, many opportunities for project collaboration may 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 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. 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 ESRI (Environmental Systems Research Institute) ArcView GIS. ArcView interfaces effectively with other software running on the Microsoft Windows operating system. Also, using a variety of tools, including the Windows help software, a Microsoft Visual Basic graphics viewer program, the ArcView legend editor, and the Avenue script language, has allowed query and automatic display of published map information in the GIS.

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 Microsoft Windows help file. After testing several options, NPS developers have been implementing the Windows help system.

This approach begins with the creation of the Help file table of contents (object table). The table includes a title, a listing all source map units (sorted by geologic age), and a list of source map references and notes. Text descriptions of map units, paginated by geologic age, are entered next. For compiled geologic maps, maps produced from more than one source map, a unit's description often consists of multiple map unit descriptions. At the end, the source map references and notes text, also one per page, were entered. Help context IDs (HELP_ID), topic names, keywords, page numbers, and linking codes were then added to the footnotes of each page. The data was then saved as a rich text format (.rtf) file, and compiled into a Windows help file.

Once compiled, the Windows help file can be opened and used with almost any Microsoft 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 (GLG_SYM, see data model below) and the corresponding help context ID (HELP_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 interactively 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 Microsoft Visual Basic (VB) graphics viewer program. The cross sections are scanned digital graphics files (JPEG format) 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., "gq1516a.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.

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 (CODESEC, see data model section below) 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.

GIS Map Unit Legend
In ArcView, theme legends can be customized to reproduce map feature symbols and colors of published source maps. To represent map features of a particular theme, an attribute field is selected in that theme's legend editor that relates map feature type with legend symbol type and color. In the NPS geology-GIS data model (presented below), the attribute field that denotes map feature type is typically either COV_TYPE for point themes or COV_LT for line themes, where COV represents the theme/coverage abbreviation. For polygon themes (themes typically representing geologic map units of areal extent), and also for point and line themes that represent point and line geologic map units, respectively, GLG_AGE_NO is the attribute field that relates feature type with symbol type (pattern) and color. As mentioned in the data dictionary section of the paper, the GLG_AGE_NO is a numeric attribute field also used to sort map units by geologic time. For point symbols that indicate or represent directionality, ArcView also allows for those symbols to be aligned to their correct orientation using a second attribute or rotation field. For attitude observation points, (e.g. strike and dip of bedding, trend and plunge of inclusions ..), which is the only coverage presently in the data model that has oriented point symbols, the ATD_AV_ROT field designates the desired symbol rotation value.

When a theme legend is completed, it can be saved as an ArcView legend file (.avl extension). In the data model, a legend file is named as per the theme/coverage file name. By default in ArcView, if a legend file exists with the same file name as a theme, when that theme is added to a view, the legend file is automatically loaded.

REVISED DRAFT NPS GEOLOGY-GIS DATA MODEL

As mentioned above, a standard geology-GIS data model has been developed for the National Park Service Geologic Resources Inventory (GRI). The model is based on ArcInfo and integrates with new user-friendly ArcView GIS software. As per ArcView and dBase requirements, database field names have been limited to ten characters or less. In addition, although many modern operating systems allow for long file names, theme/coverage file names within the model adhere to the 8.3 file name convention. Typically, themes/coverages and associated table file names are seven characters in length. The use of only seven characters allows for an additional character to be appended to a coverage name for related look-up tables. For an NPS unit digital geologic map, the first four characters or prefix of a coverage name (CODE) are the NPS unit's alpha code. The next three characters (suffix) abbreviate the type of geologic coverage (COV). As mentioned above, for INFO look-up tables associated with a coverage, an additional or eighth character, typically an integer, is appended to the theme/coverage name. An exception to the file naming convention presented above is arc/line map features of a polygon theme/coverage. ArcInfo allows for both arc/line and polygon labels to exist within the same (polygon) coverage, however, ArcView does not. Thus two themes are needed to present both the arc/line and polygon attribution of an ArcInfo polygon coverage in ArcView. For an ArcView arc/line theme associated with a polygon coverage, an 'A' (arc) is appended to the seven character polygon file name.

As with any digital map model, alterations and additional components, many derived from unique or uncommon map components, continue to advance and expand the model.

GEOLOGIC THEMES

The NPS geology-GIS model's data themes or coverages are listed below.

CODEGLG poly/line Map units or main geologic spatial data containing both polygon data describing the map units and linear data describing the interface between those units.
CODEGLN line Map units or main geological spatial data
CODEGPT point Map units or main geological spatial data represented as points due to map scale limitations.
CODEFLT line Faults.
CODEFLD line Linear fold axes/hingelines.
CODEATD point Attitude observation points.
CODEDAT point Age-date sample location points (fossil or radiometric age estimates) .
CODEVNT point Volcanic vents, eruptive centers, features mapped as points.
CODEVLN line Linear volcanic crater, eruptive and flow features.
CODEDKE line Individual lithologic dikes.
CODEDKS poly/line Areas of lithologic dikes too numerous to map as individual segments (e.g. dike swarms).
CODEMIN point Mine and mining related features.
CODESEC line Cross section lines.
CODEASH poly/line Volcanic ash map units containing both polygon data describing the map units and linear data describing the interface between those units.
CODEMET line Metamorphic grade boundaries.
CODEMOR line Linear glacial moraine features.
CODEJLN line Linear joint features.
CODELN# line Contour and other lines.
CODESPF point Geologic point data deemed sensitive by NPS Unit.
# denotes a number assigned to theme/coverage name.

COVERAGE DATA DICTIONARY

At present, all of the 19 themes/coverages presented in the data model have been evaluated and adapted into a coverage data dictionary. Of note, each theme/coverage has several attribute fields that ArcInfo adds automatically to coverage. For polygon and point coverages, AREA, PERIMETER, CODECOV# and CODECOV-ID are added to the coverages polygon attribute table (.pat) . For arc/line coverages and polygon coverage arc/line attribution, FNODE#, TNODE#, LPOLY#, RPOLY#, CODECOV# and CODECOV-ID are added to the coverages arc attribute table (.aat). As noted within a coverage's FIELD DESCRIPTION /COMMENTS, several of these ArcInfo attribute field names are changed upon conversion to a ArcView (.shp) shape file. To limit the length of this paper, only four data model themes/coverages are presented. In addition to the themes presented, two INFO look-up tables relating to map source information (CODEMAP) and additional lithology unit data (CODEGLG1) are also presented. Figure 1 illustrates relationships among data model themes/coverages presented in this paper to INFO and dBase database tables and the Windows Help File System (CODEGLG.HLP).

Simplified relationships among database tables presented in data dictionary

Figure 1. Simplified relationships among database tables presented in data dictionary. Bold type denotes
database file names for ArcInfo (top) and ArcView (below). The tabular relationships are coded with
"m" for many, and "1" for one. Related field or key names are in italics. Table types are in parentheses.

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SPATIAL THEME (FILENAME): Area Geologic Map Units (CODEGLG)
THEME DESCRIPTION: Polygon and Arc/line coverage(s)
TABLE COVERAGE/FILE NAME: CODEGLG.PAT (ArcInfo), CODEGLG.DBF (ArcView)
TABLE FORMAT: INFO table (ArcInfo), dBase IV (ArcView)
NUMBER OF FIELDS: 10

FIELD NAME TYPE-WIDTH FIELD DEFINITION
AREA F-4 area of the polygon
PERIMETER F-4 perimeter of the polygon (in map units)
CODEGLG_ B-4 unique internal (PAL) sequence number for each polygon, ArcInfo CODEGLG#, converted in shape file .dbf
CODEGLG_ID B-4 sequence ID-number for each polygon, ArcInfo CODEGLG-ID, converted in shape file .dbf
GLG_IDX I-6 user-defined ID-number for each polygon
GLG_SYM C-12 age-lithology unit symbol, used to relate coverage with the CODEGLG1.INF look-up table
USGS_SYM C-12 geologic symbol from USGS geologic map(s)
GLG_AGE_NO N-7.4 number to age-sort units in legend
GMAP_ID I-6 unique number that relates map feature to series and citation information in CODEMAP.INF look-up table
HELP_ID C-12 code (code typically GLG_SYM value) used to link to associated geologic text in Help File System

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SPATIAL THEME (FILENAME): Geologic Map Unit Boundaries/Contacts (CODEGLG (ArcInfo)/CODEGLGA (ArcView)
TABLE COVERAGE/FILE NAME: CODEGLG.AAT (ArcInfo), CODEGLGA.DBF (ArcView)
TABLE FORMAT: INFO table (ArcInfo), dBase IV (ArcView)
NUMBER OF FIELDS: 11
FIELD NAME TYPE-WIDTH FIELD DEFINITION
FNODE_ B-4 internal number of arc segment From Node, ArcInfo FNODE#, converted in shape file .dbf
TNODE_ B-4 internal number of arc segment To Node, ArcInfo TNODE#, converted in shape file .dbf
LPOLY_ B-4 internal left polygon number of arc segment, ArcInfo LPOLY#, converted in shape file .dbf
RPOLY_ B-4 internal right polygon number of arc segment, ArcInfo RPOLY#, converted in shape file .dbf
LENGTH F-4 length of arc segment
CODEGLG_ B-4 unique internal sequence, ArcInfo CODEGLG#, converted in shape file .dbf
CODEGLG_ID B-4 sequence ID-number for each polygon, ArcInfo CODEGLG-ID, converted in shape file .dbf
GLGCNT_IDX I-6 user-defined ID-number for each arc segment
GLGCNT_TYP I-2 code value for type of polygon (contact) boundary*
FLTCNT C-1 flags lithologic contacts that are also faults*
GMAP_ID I-6 unique number that relates map feature to series and citation information in CODEMAP.INF look-up table
* see Field/Attribute Code Value Lists below

FIELD/ATTRIBUTE CODE VALUE LISTS:

GLGCNT_TYP (polygon boundary/geologic contact type code)
1 known location
2 approximate location
3 concealed
4 queried
5 approximate location, queried
6 concealed, queried
7 inferred location
8scratch boundary
9 gradational boundary
10 quadrangle boundary
11 extent/map boundary
12 shoreline
13 shoreline, approximate
14 ice boundary
15 ice boundary, approximate

FLTCNT (contact a fault?)

Y Yes, the lithologic contact is also a fault.
N No, the lithologic contact is not also a fault.
Special Note: A contact arc segment that is also a fault (FLTCNT = 'Y') has the down-thrown block on the right side of the arc. Thus, the down-thrown fault-block should be the arc segment's RPOLY_.

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SPATIAL THEME (FILENAME): Geologic Faults (CODEFLT)
THEME DESCRIPTION: Arc/line coverage
TABLE COVERAGE/FILE NAME: CODEFLT.AAT (ArcInfo), CODEFLT.DBF (ArcView)
TABLE FORMAT: INFO table (ArcInfo), dBase IV (ArcView)
NUMBER OF FIELDS: 15
FIELD NAME TYPE-WIDTH FIELD DEFINITION
FNODE_ B-4  
TNODE_ B-4  
LPOLY_ B-4  
RPOLY_ B-4  
LENGTH F-4 length of arc segment
CODEGLG_ B-4 unique internal sequence, ArcInfo CODEFLT#, converted in shape file .dbf
CODEGLG_ID B-4 sequence ID-number for each polygon, ArcInfo CODEFLT-ID, converted in shape file .dbf
FLT_IDX I-6 user-defined ID-number for each arc
FLT_SEG_N I-3 number for each fault segment
FLT_SEG_T I-2 code value used to differentiate fault segment line types*
FLT_TYPE I-2 code value for type of fault offset/displacement*
FLT_LT I-3 fault and line segment type code value used for line representation*
FLTCNT C-1 flags faults that are also contacts*
FLT_NM C-60 fault name, if any, common to all arc segments with the same FLT_IDX.
GMAP_ID I-6 unique number that relates map feature to series and citation information in CODEMAP.INF look-up table
* see Field/Attribute Code Value Lists below

FIELD/ATTRIBUTE CODE VALUE LISTS:

FLT_SEG_T (geologic fault segment line type code)
1 known location
2 approximate location
3 concealed
4 queried
5 approximate location, queried
6 concealed, queried
7 inferred location

FLT_TYPE (fault offset/displacement type code)

1 thrust fault
2 reverse fault
3 low angle normal fault
4 normal fault
5 right lateral strike-slip fault
6 left lateral strike-slip fault
7 reverse right lateral strike-slip fault
8 reverse left lateral strike-slip fault
9 normal right lateral strike-slip fault
10 normal left lateral strike-slip fault
11 unknown offset/displacement
FLT_LT (line type code)
1 thrust fault
2 thrust fault, approximate location
3 thrust fault, concealed
4 thrust fault, queried
5 thrust fault, approximate location, queried
6 thrust fault, concealed, queried
7 thrust fault, inferred location
8-137 as per FLT_TYPE concatenated with FLT_SEG_T

FLTCNT (fault also a contact?)

Y Yes, the fault is also a contact between different map units.
N No, the fault is not a contact between different map units

Special Note: A fault arc segment (FLTCNT = 'Y') has the down-thrown block on the right side of the arc. Thus, the down-thrown fault-block should be the arc segment's RPOLY_.

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SPATIAL THEME (FILENAME): Attitude Observation Points (CODEATD)
THEME DESCRIPTION: Point Coverage
TABLE COVERAGE/FILE NAME: CODEATD.PAT (ArcInfo), CODEATD.DBF (ArcView)
TABLE FORMAT: INFO table (ArcInfo), dBase IV (ArcView)
NUMBER OF FIELDS: 10
FIELD NAME TYPE-WIDTH FIELD DEFINITION
AREA F-4  
PERIMETER F-4  
CODEATD_ B-4 internal number for each point, ArcInfo CODEATD#, converted in shape file .dbf.
CODEATD_ID B-4 sequence ID-number for each point, ArcInfo CODEATD-ID, converted in shape file .dbf.
ATD_IDX I-6 user-defined ID-number for each point
FIELD NAME TYPE-WIDTH FIELD DEFINITION
ATD_TYPE I-2 code value for type of attitude measurement*
ATD_ST I-3 azimuth of strike or trend, (0-359) degrees clockwise from the north with dip direction clockwise from strike direction (right-rule method). Non-applicable strike values assigned a value of 999.
ATD_DP I-2 dip or plunge degrees from horizontal
ATD_AV_ROT I-3 ArcView symbol rotation value field, used for symbol presentation
GMAP_ID I-6 unique number that relates map feature to series and citation information in CODEMAP.INF look-up table
* see Field/Attribute Code Value Lists below

FIELD/ATTRIBUTE CODE VALUE LISTS:

ATD_TYPE (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 horizontal beds
5 strike and dip of beds, tops known from sedimentary structures
6 strike and dip of overturned beds, tops known from sedimentary structures
7 strike and dip of beds, tops known from sedimentary structures, dot indicates top of beds
8 strike and dip of variable bedding
9 approximate strike and dip of beds
10 strike of beds, dip amount unspecified
11-73 additional attitude point features types

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SPATIAL THEME (FILENAME): Cross Section lines (CODESEC)
THEME DESCRIPTION: Arc/line coverage
TABLE COVERAGE/FILE NAME: CODESEC.AAT (ArcInfo), CODESEC.DBF (ArcView)
TABLE FORMAT: INFO table (ArcInfo), dBase IV (ArcView)
NUMBER OF FIELDS: 12
FIELD NAME TYPE-WIDTH FIELD DEFINITION
FNODE_ B-4  
TNODE_ B-4  
LPOLY_ B-4  
RPOLY_ B-4  
LENGTH F-4 length of arc segment
CODESEC_ B-4 unique internal sequence, ArcInfo CODESEC#, converted in shape file .dbf
CODESEC_ID B-4 sequence ID-number for each polygon, ArcInfo CODESEC-ID, converted in shape file .dbf
SEC_IDX I-6 unique ID-number for each cross section line
SEC_ABV_O C-6 initial cross section abbreviation on geologic map
SEC_ABV C-6 cross section abbreviation on digital map
SEC_FILE C-60 file directory path and graphics file name of cross section .jpg file (ex. d:\gis-blca\graphics\I584a.jpg)
GMAP_ID I-6 unique number that relates map feature to series and citation information in CODEMAP.INF look-up table

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ACCESSORY DATA FILES

Additional data on unit lithology and source map information are included in two look-up tables that are related to map coverages through a primary or secondary key field.

TABLE COVERAGE/FILE NAME: CODEGLG1.INF (ArcInfo), CODEGLG1.DBF (ArcView)
TABLE FORMAT: INFO table (ArcInfo), dBase IV (ArcView)
NUMBER OF FIELDS: 11

FIELD NAME TYPE-WIDTH FIELD DEFINITION
GLG_SYM C-12 age-lithology unit symbol, used to relate the coverage with the CODEGLG1.INF or CODEGLG1.DBF
GLG_NAME C-100 formal name of map unit, if any
G_REL_AGE C-5 relative age of geologic units
G_SSCR_TXT C-6 subscript from the map symbol
GLG_AGE_NO N -7.4 number to age-sort map units in legend
G_AGE_TXT C-50 geologic time period of map unit
G_MJ_LITH C-3 code value for lithologic type*
G_LITH_ID I-10 code value used to describe lithology
G_LITH_TXT C-100 brief text describing lithology
G_NOTE_TXT C-254 descriptive notes about the map unit
GMAP_SRC C-100 source map(s) with organization and map series number (i.e. USGS GQ-1402, USGS GQ-1568)
* see Field/Attribute Code Value Lists below

FIELD/ATTRIBUTE CODE VALUE LISTS:

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 CODEGLG1.INF or CODEGLG1.DBF

GLG_SYM = Qvba(pc)
GLG_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_ID = 71
G_LITH_TXT = basaltic andesite flows
G_NOTE_TXT = volcanic lava flows with interbedded soil horizons
GMAP_SRC = I-757; GQ-1082

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TABLE COVERAGE/FILE NAME: CODEMAP.INF (ArcInfo), CODEMAP.DBF (ArcView)
TABLE FORMAT: INFO table (ArcInfo), dBase IV (ArcView)
NUMBER OF FIELDS: 18

FIELD NAME TYPE-WIDTH FIELD DEFINITION
GMAP_ID I-6 unique ID-number of map citation
GMAP_PARK C-30 list of NPS Unit alpha codes map is relevant to
GMAP_CODE C-4 unique 4-letter abbreviation code of map
GMAP_ABBRV C-150 abbreviation of map title, often includes map name and interpretation technique (e.g., Preliminary) and/or a map emphasize term on the distribution of specific materials (e.g., Surficial).
GMAP_YEAR I-4 compilation or publication year
GMAP_AUTH C-254 map author(s)
GMAP_ORG C-100 organization that created or compiled the map
GMAP_TITLE C-200 complete map title
GMAP_SER C-40 map series or organizational identifier (e.g., USGS GQ-1516)
GMAP_SCALE I-7 source map scale denominator
GMAP_PROJ C-100 name or description of map projection with projection datum
GMAP_REF C-254 complete map citation in USGS style
GMAP_DESC C-254 brief description of the map
GMAP_XMAX F-8.6 western limit of map in decimal degrees
GMAP_XMIN F-8.6 eastern limit of map in decimal degrees
GMAP_YMAX F-8.6 northern limit of map in decimal degrees
GMAP_YMIN F-8.6 southern limit of map in decimal degrees
GMAP_SRC C-100 source map(s) with organization and map series number (i.e. USGS GQ-1402, USGS GQ-1568)

Example record for the Geologic map of Rocky Mountain National Park and Vicinity, Colorado. The 4-letter NPS alpha code for Rocky Mountain NP is ROMO.

ROMOMAP.INF or ROMOMAP.DBF

GMAP_ID = 144
GMAP_PARK = ROMO
GMAP_CODE = ROMO
GMAP_ABBRV = Rocky Mountain NP
GMAP_YEAR = 1990
GMAP_AUTH = Braddock, William A., and Cole, James C.
GMAP_ORG = USGS
GMAP_TITLE =Geologic map of Rocky Mountain National Park and Vicinity, Colorado
GMAP_SER = I-1973
GMAP_SCALE = 50000
GMAP_PROJ = Geographic
GMAP_REF = Braddock, William A., and Cole, James C., 1990, Geologic map of Rocky Mountain National Park and Vicinity, Colorado, USGS, I-1973, 1:50,000 scale
GMAP_DESC = Geologic map of Rocky Mountain National Park and adjacent vicinity.
GMAP_XMAX = -105.958333
GMAP_XMIN = -105.458333
GMAP_YMAX = 40.566666
GMAP_YMIN = 40.125000
GMAP_SRC = see published USGS non-digital (paper) map.

REFERENCES

Gregson, Joe D., Fryer, S. L., Poole, Anne, Heise, Bruce, Connors, Tim, and Dudek, Kay, 1999, Geologic Resources Inventory for the National Park System: Status, Applications, and Geology-GIS Data Model, in D.R. Soller, ed., Digital Mapping Techniques '99--Workshop Proceedings: U.S. Geological Survey Open-File Report 99-386, p. 151-162, https://pubs.usgs.gov/openfile/of99-386/gregson.html.

Gregson, Joe D., 1998, Geologic Resources Inventory--Geologic Resources Division, Inventory and Monitoring Program, in D.R. Soller, ed., Digital Mapping Techniques '98--Workshop Proceedings: U.S. Geological Survey Open-File Report 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 ArcInfo Data Model Example, in D.R. Soller, ed., Digital Mapping Techniques '98--Workshop Proceedings: U.S. Geological Survey Open-File Report 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: American Assoc. of State Geologists/U.S. Geological Survey Geologic Map Data Model Working Group, May 19, 1998, http://geology.usgs.gov/dm/model/Model42.pdf

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Maintained by Dave Soller
Last updated 11.03.00