How are different geologic features stored in DVGQ databases?
Features that make up the geologic map are stored as individual shapefiles in a directory named for the 7.5-minute quadrangle. As many as 14 different themes make up the database, but not all are present for every quadrangle. Each quadrangle folder contains a computer image in .jpg format that shows all shapefiles with appropriate symbolization. The image files can be viewed in your web browser or in an image editor.
FGDC-compliant metadata about the shapefiles can be viewed in your web browser by clicking the file "quadname".htm ("quadname" is the name of the quadrangle) under the folder that contains the quadrangle data (named by quadrangle).
Each quadrangle uses a four-letter abbreviation for the shapefile name, and a two- to four-letter code is used for the theme type. For example, the fault features for the Alcorn quadrangle are stored in a set of files with the prefix "alcoflt". In the following descriptions the standard file assignments are designated on the first line, with XXXX indicating the quadrangle abbreviation. Each shapefile theme has attribute data that describe characteristics of individual features in the file. The attributes are either in character (C) or integer (I) format. FGDC metadata files for each quadrangle data set are supplied in web browser format (quadname.htm). The following describes the nature of each theme and how its attributes are used.
Formation Areas: XXXXFMP (polygon)
This file contains the surficial areas of rock units that compose the geologic map, and is therefore the most important shapefile. Rock units are labeled using stratigraphic nomenclature that indicates geologic age, superposition, and rock type. These units may be ranked as groups, formations, members, or beds. This shapefile also contains fault segments or map borders necessary to bound a map unit.
Formation area shapefile attributes and example values
Formation Contacts: XXXXFMA (line)
Each rock unit is bounded by an upper and lower surface called a contact. In some cases other rock units, such as coal beds, are used as a proxy for a formation contact. Contacts may be classified according to exposure characteristics and the confidence with they were delineated.
Formation contact shapefile attributes and example values
Structural Features: XXXXSTRA (line)
Contains the structure lines, including structure contours, erosional surface contours, and anticlinal and synclinal axes. This shapefile also contains the datum change boundaries.
Structural feature shapefile attributes and example values
Structural Measurements: XXXXSTRP (point)
Describes strike and dip measurement locations for both bedding and joint surfaces.
Structural measurement shapefile attributes and example values
Faults: XXXXFLT (line)
Contains faults, fractures, and fault scarps.
Fault shapefile attributes and example values
Thin Beds: XXXXBED (line)
Contains rock units that were too thin to digitize as polygons (generally less than 25 feet thick). Informal units are identified by lithology.
Thin bed shapefile attributes and example values
Coal Locations: XXXXCLP (point)
Contains coal outcrop locations identified during the GQ mapping. Does not describe thickness or elevation characteristics of the coal. More comprehensive data about coal locations are available from the KGS database (www.uky.edu/KGS/pubs/lop.htm).
Coal location shapefile attributes
Economic Features: XXXXECNA (line)
Contains arcs of mineral veins (e.g., barite and fluorite veins) and mine outlines. Other "non-coal" economic arcs may be included within this theme.
Economic feature shapefile attributes and example values
Economic Locations: XXXXECNP (point)
Contains points of non-coal and economically significant mineral outcrops and prospects, mines, quarries, pits, shafts, etc. The type of minerals that are economically significant include limestone, phosphate, clay, iron, barite, fluorite, sphalerite, etc.
Economic location shapefile attributes and example values
Drill-Hole Locations: XXXXDH (point)
Contains locations of drill holes and wells that were deemed "geologically" significant by compilers. More comprehensive and up-to-date data about oil and gas, coal, and water wells are available from the KGS database (www.uky.edu/KGS/pubs/lop.htm).
Drill hole shapefile attributes and example values
Intrusive Features: XXXXDIKE (line)
Contains areas of intrusive dikes and sills. These may include igneous or sedimentary features.
Intrusive feature shapefile attributes and example values
Intrusive Locations: XXXXDIKE (point)
Contains points of intrusive dikes and sills. These may include igneous or sedimentary features.
Intrusive location shapefile attributes
Fossil Locations: XXXXFSLP (point)
Contains fossil locations and sample sites.
Fossil location shapefile attributes
Fossil Horizons: XXXXFSLA (line)
Contains fossil layers and sample transects.
Fossil horizon (layer) shapefile attributes
Miscellaneous Linear Features: XXXXMISA (line)
Miscellaneous linear data. Includes outcrop extents of uneconomic lithologies and geologic features such as paleochannels and lineaments.
Miscellaneous linear feature shapefile attributes and example values
Miscellaneous Locations: XXXXMISP (point)
Miscellaneous locations such as non-coal outcrop points, boulders, and blocks of geologic material.
Miscellaneous location shapefile attributes and example values