United States Department of the Interior
U.S. Geological Survey

Aeromagnetic Survey of parts of Wisconsin
RFP No.: 98CRSS1015
Contract No.: 98CRCN1015

Survey and processing by High-Sense Geophysics Limited, 1998-1999



The following line-data files are provided on 4 CD's:


    Overall Summary File

        ln_all.txt - this file


    Summary Text Files of Each Data File

        ln_01.txt
        ln_02.txt
        ln_03.txt
        ln_04.txt
        ln_05.txt
        ln_06.txt
        ln_07.txt
        ln_08.txt
        ln_09.txt
        ln_10.txt
        ln_11.txt
        ln_12.txt
        ln_21.txt
        ln_31.txt


    ASCII XYZ Data Files

        ln_01.asc
        ln_02.asc
        ln_03.asc
        ln_04.asc
        ln_05.asc
        ln_06.asc
        ln_07.asc
        ln_08.asc
        ln_09.asc
        ln_10.asc
        ln_11.asc
        ln_12.asc
        ln_21.asc
        ln_31.asc


The digital line profile data for the Aeromagnetic Survey of
parts of Wisconsin are contained within 14 ASCII XYZ files. Files
ln_01.asc to ln_12.asc are for the main block, file ln_21.asc is
for block B and file ln_31.asc is for block C. There are
corresponding text line summary files named ln_01.txt, etc. for
each XYZ file.  These contain a listing of the survey line
numbers with statistics for each line contained in the XYZ file.



The following is a list of the ASCII XYZ files


File name    Line# Range      File Size (bytes)
----------   ------------   ------------
ln_01.asc      13 -   481   135,990,090  travesre lines
ln_02.asc     491 -   900   172,657,980  traverse lines
ln_03.asc     910 -  1401    87,104,970  traverse lines
ln_04.asc    1410 -  1860   115,881,354  traverse lines
ln_05.asc    1870 -  2320   144,728,856  traverse lines
ln_06.asc    2330 -  2792   222,199,362  traverse lines
ln_07.asc    2800 -  3251   222,197,094  traverse lines
ln_08.asc    3261 -  3653   176,648,040  traverse lines
ln_09.asc    3660 -  4060   209,548,620  traverse lines
ln_10.asc    4070 -  4780   166,287,492  traverse lines
ln_11.asc    5017 -  5300    95,247,576  control lines
ln_12.asc   11610 - 21970    81,623,538  traverse lines
ln_21.asc     770 - 20071   162,858,924  traverse & control lines
ln_31.asc   11601 - 50080   107,099,658  traverse & control lines



ASCII XYZ description:  (See format. file for more details)


Channel  Description                                      Units
-------  -----------------------------------------------  -------
1        Flight line number
2        Flight line direction-flown code
3        Longitude NAD27 (decimal degrees)                degrees
4        Latitude NAD27 (decimal degrees)                 degrees
5        X, UTM Easting                                   metres
6        Y, UTM Northing                                  metres
7        Fiducial
8        Date (Year minus 1900 and Day of the year)       YY
9                                                         DDD
10       Time (UTC)                                       HH
11                                                        MMSS
12       Radar Altimeter                                  metres
13       Barometric Altimeter                             metres
14       GPS Altimeter                                    metres
15       Diurnal                                          nT
16       Raw Mag                                          nT
17       Diurnally corrected Mag                          nT
18       IGRF Corrected Mag                               nT
19       Final levelled IGRF Corrected Mag (+56225 nT)    nT



UTM projection parameters

Spheroid:            Clarke 1866 (NAD27)
Projection:          UTM
Local Datum:         Mean Continental United States, offset x=8,y=-160,z=-176
Central Meridian:    87 degrees West (-87 degrees)
False Easting:       500000 metres
False Northing:      0