Note: the information on this site was copied from an optical medium publication.

Although all data and software published on this CD-ROM have been used by the USGS, no warranty, expressed or implied, is made by the USGS as to the accuracy of the data and related materials and/or the functioning of the software. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of this data, software, or related materials.   

This CD-ROM has been produced in accordance with the ISO 9660 CD- ROM Standard and is therefore capable of being read on any computing platform that has appropriate CD-ROM driver software installed.  However, the access software used on the disc currently executes only under DOS on IBM or compatible personal computers.

OVERVIEW

This CD-ROM contains gridded geophysical data, images generated from the data, software for displaying and analyzing the images, software for processing potential-field (gravity and magnetic) geophysical data, and documentation files that describe the data and software.  The gridded data include gamma-ray data (uranium, thorium, and potassium channels), Bouguer gravity data, isostatic residual gravity data, aeromagnetic anomalies, topography, and topography with bathymetry.  These data are available in ASCII format under the ASCII directory.  This publication contains only data from the conterminous United States.

The images on this CD-ROM include graytone and color images of each gridded data set, color shaded-relief images of the potential-field and topographic data, color composite images of the gamma-ray data, and color composite images of potential-field data painted on shaded and edge-enhanced topography.  These images are 8-bit data and can be imported for viewing by many different software packages, but the color display tables are only designed for DOS computers and displays.  The display and analysis software includes the ability to register images with geographic and geologic overlays, generate three-color composite images for display on a super VGA video system, generate perspective view images, and analyze images in five dimensions.

The potential-field software on this CD-ROM can be used to extract subsets of the geophysical data, process them, and display them as images or contour maps.  The software can also be used to generate gridded data from point data, generate profiles from grids, and generate geological models from gridded or profile data.  This software is written in FORTRAN and, with minor modifications, can be adapted to a variety of computer systems.

The documentation files reside under the directory DOSMENU\DOCFILES and are named with a suffix of DOC.  This directory also contains a WordPerfect 5.1 file (CDROM.WPS) that contains all of the documentation.

This CD-ROM is released in the Digital Data Series of CD-ROM's produced by the U.S. Geological Survey.  This new publication series is intended to improve distribution of important earth science information to the public.  The disc contains the results  of work performed by the U.S. Geological Survey.

INSTALLATION

If you have not already done so, run the INSTALL program by making the CD-ROM drive the active drive and typing INSTALL followed by pressing the key.  Follow the instructions printed on the screen.  When the INSTALL program is finished, it will invoke the national geophysics (NATGP) menu program, and you will see a menu of your options.

If you have previously run the INSTALL program and you have added C:\ to the PATH statement in your AUTOEXEC.BAT file, run the menu program directly by typing NATGP followed by pressing the  key.  If C:\ is not in your search path, you will have to type C:\NATGP followed by pressing the key.  A menu of your options will appear on the screen.