This Folder:  mag\
This File:    read_4th.txt


Report Title:     Aeromagnetic Surveying in Wisconsin 1998-99:
                     Digital Data Files
Report Authors:   Robert E. Bracken and Suzanne W. Nicholson
Report Document:  U.S. Geological Survey Open-File Report 99-527



Description of This Folder and Its Content:

This folder contains a gridded data set of the final leveled
magnetic data as supplied by the contractor.  The grid interval
is 200 meters and the grid size is 1960 columns by 1894 rows.
Various grid formats are included.  This folder is designated by
the following path:

\data\grid\mag\


In this folder, you will find the following files:


gxf_hdr.txt  A copy of the header information provided in the
             wiscmag.gxf grid file.  This header includes all of
             the essential grid and projection information in a
             directly readable form.

read_4th.    (This file.)  Contains information describing this
             folder and its contents.

wiscmag.asc  An ASCII version of the wiscmag.sf grid file.

wiscmag.e00  An ARC interchange format grid.  The No-data value
             is -0.34028234663853E+39.  This grid is mostly
             ASCII.

wiscmag.gd   A U.S. Geological Survey ODDF (Object Description
             Data File) grid (Webring, 1998).  This is a binary
             file with an ASCII header.

wiscmag.gxf  A Geosoft GXF (Grid Exchange Format) Grid (Geosoft,
             1998).  This is an entirely ASCII grid with
             80-character or less record lengths.  The no-data
             value is -999999.0

wiscmag.sf   A U.S. Geological Survey SF (Standard File) grid.
             This entirely binary format has also carried the
             suffix .grd, but due to the proliferation of the
             more generic suffix, the .sf suffix has been used
             here instead.  The standard file is described in
             detail in Phillips, 1997.  It is also used by the
             Potential-Field software provided elsewhere on this
             CD.