READ ME: DMCH011: WINGATE WASH MAP

This geologic map (Plate 1) and accompanying database were generated from a hybrid mapping approach during an early generation of digital geologic mapping. The field notes and orientation data were all recorded in a real-time digital recording system with GPS positioning using a handheld computer (primarily Apple Newton devices) and the Fieldworker software package. Photographs in the database were also acquired with early generation digital cameras. All geologic mapping, however, was done on conventional paper maps that were later digitized in AutoCAD and transferred to ArcInfo, where the data were georeferenced and polygons constructed from the linework. The original field maps were at a scale of 1:24,000 and were aided by coregistered black-and-white ortho-rectified aerial photographs and accompanying aerial photography that allowed stereographic viewing of the imagery. All of the authors contributed to the fieldwork, but the field maps were digitized by Luckow-Golding, Guest, and Pavlis, with the final map compilation by Pavlis. The ArcInfo work was initially completed at the California Division of Mines and Geology under Wagner's direction, and the data were cleaned and edited by Pavlis to produce the final map presented here. The data structure of the map is not ideal for extensive GIS analysis because of this hybrid approach, but most of the original field data are archived here in the station notes and notes accompanying the "structure" files.

A conventional paper geologic map can be produced from these files by printing the pdf file on a large format printer. However, to print that map at full scale (1:24,000) requires at least 48" paper to avoid splitting the map. The cross sections (Plate 2) and the map explanation (Plate 3) are presented as separate files for printing.

The digital files in the data set consist of an ArcGIS database and ESRI shapefiles. The ArcGIS database was generated in ArcGIS9.1, and will require software that can read that data structure, whereas the shapefiles are generic shapefiles that can be read by nearly any GIS program available circa 2000-2012. Some important features about these data files:
1) To access all of the data, readers should use the ArcGIS database which contains not only the map features, but also all of the field photographs and sketches generated by the authors. The sketches and photos are all keyed to station number by file name but are not linked directly in the database. Thus, a photograph with the name "98WP1" was taken at a station with that same name, and that station can be found in the feature class "stations" by querying the attribute table.  
2) The feature class "structure" contains all of the orientation data collected during this work. All measurements were made with conventional geologic compasses as this project pre-dated the availability of digital recording compasses.
3) The feature class "stations" carries raw station location data as UTM coordinates (NAD27 datum) and the station number as the field STATNUM. In the shapefiles, the only data carried with the files are these basic data, but in the ArcGIS geodatabase, the field STATNUM is associated with a file "Note" that carries field notes collected at each site. That "STATNUM" field is also recorded in the attribute table for the feature "stucture," but is not used in the database for location; i.e., some of the measurements were moved small distances for map clarity, but the true locations are at the position of the station where the measurement was taken.
4) The map linework has an unconventional data structure inherited from Fieldlog and AutoCAD. Faults are separated as a separate data layer, but are also included in the "geolinework" data layer. This is a consequence of the hybrid mapping approach used, and the fault layer was produced by extracting these features from the "geolinework" file because it is often useful to have these data as a separate layer. As a result, however, the attributes in the "Fault" layer are different than "geolinework." In "Faults" the attribute "Layer" is a quality attribute referring to accuracy of the contact, equivalent to traditional geologic mapping of solid vs. dashed vs. dotted lines with an equivalent to that code carried in the field "LINETYPE." In "geolinework" there is equivalent coding, but "Layer" defines a different class of line--e.g., Depositionalcontact_exposed vs. thindikes, etc.--and thus lumps all linetypes together, but like "faults" carries a "linetype" attribute equivalent to the traditional solid vs. dashed vs. dotted contact types of paper geologic mapping. Thus, to extract different line types, query the attribute table by the "LAYER" attribute, but to access line quality only, query the "LINETYPE" attribute.  
5) The other features in the database are self-explanatory by name but for clarity: "label" is a point file with a label for rock unit at that site; "foldaxes" is the axial trace of folds; "GeographicFeatures" is a point file labeling geographic reference features; "CrossSections" are the cross-section lines shown on the accompanying pdf files; and "dates" are point locations for samples dated by Luckow-Golding et al. (2005).