Geographic information system format. The digital geologic maps have been prepared for use in geographic information systems (GIS). The geologic features are rendered in "vector" format to permit scale variation without degrading quality. You should be aware, though, that the original data were compiled at a scale of 1:24,000, and uses at larger scales are not advised. Features are stored as one of three shapes: points, lines, or areas (polygons). Geometry type is indicated with the description of each theme below.

Computer file format. These data are supplied in ESRI shapefile format. Each shapefile actually consists of several files with the same name and an extension that indicates its function. You should be certain when copying shapefiles that all files with the same file name are copied together. For a complete description of the shapefile format see www.esri.com/library/whitepapers/pdfs/shapefile.pdf. You will need appropriate software to view or analyze shapefiles on your own computer. A variety of commercial and publicly available software products are available for this use. KGS does not recommend or endorse any of these products.

Selected software for using the ESRI shapefile format

ArcView/ArcGIS
ESRI

Autocad Map
Autodesk Corp.

MapInfo
MapInfo Corp.

GeoMedia
Intergraph

Smallworld GIS
GE Smallworld

Idrisi
Clark University

GRASS
Baylor University

CartoGIS
Cartographic System and Analysis

Software for viewing shapefile data:

ArcExplorer ESRI's free geographic viewer

ArcView 1.0 ESRI's ArcView Version 1 GIS Desktop Software. It also has GIS functionality, but lacks the features of the current version

CartoMap FREE Viewer supports both MapInfo Mif/Mid and ArcView Shapefiles

FME The FME Universal Viewer supports SDTS, Shapefile, IGDS, AutoCAD DXF/DWG, E00, Genamap, and DSFL formats.

GeoMaitre GeoMaitre lets you view files in E00, SHP, DGN, MIF, and DXF format

MassGIS Data Viewer Expands the functionaly of ArcView

ShapeViz Mechanism to view multiple Shapefiles

GeoBrowser This GIS interface can be configured to work on any GIS database. Built using ESRI MapObjects technology

GeoView LT Adds support for the display of AutoCAD DWG/DXF, Microstation DGN, ESRI Shapefile, MapInfo MIF, and image files, with graphic overlays, spatial queries, and links to your database quickly

Free software for converting shapefiles

Arcv2CAD Arcv2CAD converts ArcView/ESRI Shapefiles to AutoCAD DXF and DWG formats allowing shapefiles to be read by virtually all CAD software

Arcv2CAD3.2 ArcView shapefile to DXF/DWG converter Arcv2CAD3.2; newly updated

CADTools Tools for converting SHP files to DXF

SHP to Atlas Freeware ESRI SHP to Atlas Geo translator

SHP to Mapinfo MBX to convert Shapefiles to Mapinfo

SHP2MIF Export shapefiles to Mapinfo MIF

Coordinate system and datum. These data are supplied in latitude and longitude coordinates, referenced in both the North American datum of 1983 (NAD83) and the North American datum of 1927 (NAD27). NAD27 uses the Clark 1866 Reference Ellipsoid which is the basis for most of Kentucky's topographic maps. NAD83 uses the GRS80 Ellipsoid and is the prefered datum for collecting GPS data. In all other respects, these data are identical. Users who wish to compare these geologic data to other spatial information should determine first that they are in the same datum.

Quadrangle maps in latitude/longitude coordinates will appear square on the computer screen. In order to measure areas or distances, these data should first be projected. Consult your software documentation for instructions on applying a projection to these data.