Pamela Dunlap Derkey, as project chief and GIS coordinator, envisioned, managed and coordinated the GIS (geographic information systems) aspects of the regional geologic map compilation (NR_GEO dataset). Her work efforts focused on preparation of standardized spatial databases for the individual geologic map components, spatial database design, report writing, metadata (including refinement of attribute definitions), and quality checking the final GIS products. She provided input for revisions to GIS and metadata.
Robert J. Miller merged polygon and arc topology into a single spatial data file (ESRI® coverage) for many of the digital geologic maps. He also rubbersheeted all of the geologic quadrangle maps to their mathematically generated boundaries and all maps with state boundaries to 1:100,000-scale state boundary vector data. Miller wrote a variety of programs (1) to proof the individual quadrangle and national forest spatial databases for arc and polygon coding errors, (2) to manage spatial databases for the same areas that were revised in parallel so as to spatially incorporate new fields and their attributes from one version into another set of significantly updated spatial databases, and (3) to append forty-three geology map databases together in a specific sequence (to reflect priorities of one map over another) to create the regional compilation.
J. Douglas Causey developed and managed an in-house Access® relational database of map unit attribute information. He incorporated identification fields into each of the quadrangle and national forest ArcInfo® spatial databases and populated them, so each could be linked to the relational database that contained detailed geologic information. Causey reviewed the stratigraphic status of all the terms used to name geologic units using the USGS geologic names lexicon, attributed the field UNIT_TYPE in the look-up table NR_GEO.MU, and revised unit names to conform to usage specified for formal and informal stratigraphic units. Causey also managed all the information related to the age of geologic units. He converted all time units to geochronologic terms, checked consistency in coding, and created generalized time terms that are used to develop map symbols and to symbolize the database. Causey also incorporated map unit descriptions into the relational database. Causey developed a master reference list for all the map unit descriptions with assistance from Jeremy C. Larsen (contractor), Jeremiah Drewel (student), and Richard D. West (student). He indexed words in the map unit names and the map unit descriptions. He developed queries to check the integrity and quality of attribute information and to manipulate hierarchical data in the relational database. Information from the relational database was used to create the files that summarize map unit information in ArcInfo® look-up tables (NR_GEO.MU, NR_GEO.LITH, and NR_GEO.UN).
Arthur A. Bookstrom provided a new interpretation of the igneous map units and prepared the new igneous rock information for inclusion in the spatial database. Jeremy C. Larsen and Michael L. Zientek assisted with the review and revision of this information.
Mary H. Carlson (contractor) was responsible for incorporating revisions into the spatial databases and metadata. Carlson managed the data structure (arc and polygon feature attribute tables) of each of the quadrangle and national forest spatial databases (map tile) so that they could be appended together to generate a single regional database. Carlson worked with Arthur A. Bookstrom to initially capture igneous attribute information in shapefiles, and she worked with Robert J. Miller to join both igneous arc and polygon attributes, present in shapefile format, to each spatial database (map tile). Carlson created the NR_GEO.IGPNAM and NR_GEO.IGANAM ArcInfo® lookup tables from dBASE-format tables of igneous attribute information. With assistance from Miller, Carlson was able to append each individual spatial database together into one spatial database for the entire project area as the map tiles were revised. Gregory N. Green, William N. Kelley (contractor), and Mary H. Carlson (contractor), converted the attribute tables of previously prepared, digital geologic maps (generated by the Idaho Geological Survey, Montana Bureau of Mines and Geology, and USGS) into a standardized format, with assistance from Michael Koenig (student).
Thomas P. Frost devised map symbols (stored in the LAB_ASC and LAB_GAF items) for the item NAME in the NR_GEO.MU ArcInfo® look-up table. Frost was responsible for reviewing the consistency of the attributes reported in the fields LNAME_DOM and UNAME_DOM in the NR_GEO.LITH and NR_GEO.UN ArcInfo® look-up tables.
David E. Boleneus, Arthur A. Bookstrom, J. Douglas Causey, Karl V. Evans, Thomas P. Frost, Rebecca Pitts (student), Bradley S. Van Gosen, Anna B. Wilson, and Michael L. Zientek coded lithologic information in the in-house Access® relational database.
Karl V. Evans was responsible for reviewing the consistency of the attributes reported in the fields NAME_MAJOR, NAME_MAJR1, NAME_MAJR2, NAME_MINOR, and NAME_OTHER in the NR_GEO.LITH and NR_GEO.UN ArcInfo® look-up tables.
Jeremy C. Larsen and Kenneth C. Assmus (contractors) prepared rectified images of the geologic maps used to create the regional spatial database compilation. These images were used to proof the attribution of the spatial database.
Helen Z. Kayser (contractor) and Pamela Dunlap Derkey proofed and revised the attributes for the items NAME_OR, LAB_ASC_OR, LAB_GAF_OR, MINAGE_OR, and MAXAGE_OR in the map unit (NR_GEO.MU) look-up table and all of the attributes in the linecode (NR_GEO.LCD) look-up table. Kayser incorporated some of the information directly info the feature attribute tables (*.AAT and *.PAT) via a join process.
Kenneth C. Assmus (contractor) prepared ArcGIS® layer files (*.LYR) to symbolize the NR_GEO spatial database, and he prepared many of the page-size illustrations for the report that accompanies the spatial database.
QUALITY CONTROL Each spatial database (for a map tile) was proofed (prior to trying to compile the map tiles) to make sure that they were all in a geographic decimal second coordinate system, that all lines and polygons were attributed with a line or unit code, that the master map-unit look-up table contained the correct map label and unit name information, and that the information in the added identifier fields was correct. If we suspected a problem in line or polygon coding, the spatial databases were compared onscreen to georeferenced TIFF images of the original source maps and corrections to the spatial databases were made as warranted.
After the compilation was created for the first time, much proofing by many of the authors ensued over the span of a year (August 2003 through September 2004) to ensure that the spatial database for the regional compilation was ready to submit for technical review for publication: both the individual databases and the programs were revised and the databases re-compiled at least five times before the regional compilation passed a variety of quality-control checks.
Early on it was noticed that geologic units were named inconsistently between map tiles some corrections could be made by revising attribute tables. However, it was not until the forty-three map tiles were appended into a regional compilation that proofing the geologic names could be completed. The regional compilation was symbolized on NAME in ArcMapú and discrepancies were noted along the map boundaries. Depending on the context, NAME was revised. In the process of checking the boundary discrepancies, coding errors were found in the regional compilation. These were corrected in the individual map tiles. Again, a new source number was assigned for new source maps (and coding of the arcs or polygons reflect this new number).
A routine (programmed in an Arc Macro Languageú text file) was run on the regional map compilation to locate arcs that were coded incorrectly with regard to geology. Although the routine was run on the regional compilation the errors were fixed in the individual map tiles, subsequently another compilation was run after the errors were fixed. Because the routine was run on the compilation, not all arcs in the tiles were tested for these errors. There are several areas of overlap so map precedence was determined; areas with a lower precedence were removed from the compilation. Any errors that may be in the removed areas would not have been detected. The routine located and tagged lines coded as (1) contacts with the same map unit on both sides, (2) approximately located contacts with the same map unit on both sides, (3) dangling contacts in the middle of a map unit, and (4) dangling contacts with queried locations in the middle of a map unit. Each error was reviewed by comparing the spatial database to the paper source map or on-screen to a georeferenced TIFF image of the source map. Sometimes the error identified by the routine was an error in the original source map; in this case other source maps were used to interpret and correct the error. Other times it was an error in coding the original spatial database to match the source map. Arcs and polygons were recoded, deleted or sometimes added to match the source map. A new source number was assigned to additional source maps if coding or linework helped resolve one of the errors. The arcs or polygons edited during this process, due to new information or interpretation by the authors, was assigned this new source number.
Proofing then focused on the individual spatial database (map tile) boundaries and water bodies. We found that arcs defining map tile boundaries were inconsistently coded. Tile boundaries were coded with a variety of attributes (state, scratch, longitude and latitude); they were all re-coded to a single value "map boundary". In the process of checking the boundary discrepancies, arcs within the map tiles were found to be coded incorrectly as boundaries. The original sources were reviewed and appropriate corrections made.
Further corrections and revisions were made (December 2004 through June 2005) to NR_GEO (and the metadata) subsequent to technical reviews by Bruce R. Johnson, Steven E. Box, Nora B. Shew, Peter N. Schweitzer, and Lorre A. Moyer of the U.S. Geological Survey; Loudon R. Stanford and Reed S. Lewis of the Idaho Geological Survey; Karen Porter of the Montana Bureau of Mines and Geology; and Ryan Portner of the U.S.D.A. Forest Service.