If you have a question about a specific term, go straight to our glossary of GIS terms.
Geologists, hydrologists, engineers, planners, developers and development agencies, mining companies, oil and gas companies, transportation departments, etc. Anyone who can benefit from knowing the geologic conditions of a certain area.
Both vector and raster data are in the digital data sets. The vector data are included so that users who want to insert geologic features or parts of features into their own work can pick, choose, and manipulate the specific features they are interested in. The vector format permits a high degree of interaction and manipulation of the geology when using appropriate software.
Raster data are from a scanned image of the vector data plotted at 1:24,000 scale and are in jpg format. The raster data can be viewed on the computer screen or plotted on paper, but cannot be manipulated in the same way that vector data can be.
Yes, a geologic feature plotted at 1:24,000 scale from a digital data set is identical to the same feature on the USGS-KGS 1:24,000-scale published geologic quadrangle map. Great care has been taken to accurately capture all geologic features according to published standardized digitizing techniques. The digital data have been checked for accuracy against the original printed maps. Also, field verification has been done using GPS technology. The vector data are for GIS and AutoCAD software users. They are intended to provide the most flexibility possible when using the digital geologic information.
Nearly all the USGS-KGS 1:24,000-scale geologic quadrangle maps were printed by 1978. Some changes have been made to the stratigraphy of Kentucky since 1978. The changes, particularly in the coal fields, are the result of research done since the original maps were printed. The changes in stratigraphy are incorporated into the digital data sets to keep the geology of Kentucky as up to date as possible.
Geologic features such as formation contacts and faults that cross quadrangle boundaries have been digitized to remove any deviations at the boundary. For the most part these deviations were false, the result of a publishing schedule in the 1960's and 70's that handled each map separately, therefore not requiring the neighboring maps to match perfectly. One of the benefits of the digital data sets is that the geologic features are matched with all neighboring quadrangles to ensure reasonable continuity of lines across quadrangle boundaries.
These digital data sets are computer files that contain geologic features from the USGS-KGS 1:24,000-scale geologic quadrangle maps. To call the data sets digital geologic maps is a misnomer, because they are not intended to produce a print-on-demand geologic map. However, the digital data sets contain features that can be used to make a printed geologic map. The difference is that the features in the digital data set are separately labeled files to be accessed or loaded into GIs or AutoCAD software, depending on the needs of the user. Because they are separate files, they provide users with a high level of flexibility for their individual needs.
Yes. The digital data sets contain a scanned image of the digital geologic information in a "jpg" file. The scanned image (jpg) is a raster format, which can be viewed on the computer screen or plotted on paper, but cannot be manipulated in the same way that the vector data can be.
All data are created with ESRI software, ARC/INFO versions 7 and 8, ArcView 3.X, and ArcGIS 8.1.
All data are originally acquired in ESRI ARC/INFO format (coverage). But, KGS will release the data as ESRI shapefiles in latitude-longitude coordinates in North American datum 1983 (NAD83), as well as North American datum 1927 (NAD27). Most major GIs software packages, such as MapInfo, GeoMedia (Intergraph), and SmallWorld, support the ESRI shapefiles. AutoCAD MAP also can import ESRI shapefiles.
Most geographic data packages are now importing the SDTS format by USGS. This format is a standard that allows for maximum compatibility across different software packages and operating systems. For more information about SDTS, visit USGS's Spatial Data Transfer Standard (SDTS) Web page.
Metadata is "data about data." It is used to describe certain aspects of a data set. Metadata for the coverages created by the Digital Geologic Mapping Group describe several things: the geographic extents of the coverage, dates that the coverage was created and modified, original authorship of the map, person(s) who digitized the data, person(s) to contact if questions arise about the data, stratigraphic decisions that were made, and many other aspects too numerous to mention. All of the Digital Geologic Mapping Group's metadata are FGDC-compliant. Visit FGDC's Metadata Web page for further information.
We plan to have all 707 of the 7.5-minute geologic quadrangle maps that cover Kentucky digitized by 2003. But the Harrodsburg area will be released October 1, 2001, followed by Lexington and Falmouth areas by 2002. The cost for each 7.5-minute quadrangle data set has been determined to be $10.
Depending on the software program being used, almost any database file that contains spatial coordinates can be used in conjunction with these data. For example, oil-well data obtained from KGS containing the latitude and longitude of the wells can be easily overlaid on top of these data as an "Event Theme" in ArcView.