|
|
|
|
|
|
|
|
|
|
|
|
4040 |
Northwest Illinois |
Div.Tech. |
04/81 |
3 mi. |
E-W |
1800 B |
1455 |
IGRF75 |
OF82-190 |
|
4163 |
Wabash Valley |
Aerodat |
11/94 |
0.28 mi. |
N65W |
500 AG |
3800 |
DGRF, 54314 |
SeisResLetv68 |
Description of Table
No.: Internal USGS
identification number
Name: Internal project name (not always the name used in
publication title)
Flown By: Company or government agency who flew the original
survey
Spacing and Dir.: Primary flight-line spacing and
primary flight-line direction
Altitude: Primary flight altitude in feet; B = barometric
elevation, AG = above ground draped over topography
LnMi.: Approximate total of line miles flown for this survey
Datum: Indicates if a regional field was removed and, if
it could be determined, the base value removed. Total field = no regional
was removed. Arb. (arbitrary) datum = the base value removed was not
stated on the map or in survey reports.
Publication: Brief publication reference*. USGS publications are listed as: Open-File reports
= OFxx-yyyy where xx is the publication year, Bulletins and Professional
Papers = B-yyyy or P-yyyy, Geophysical Maps = GP-yyyy, Miscellaneous
Field Studies Maps = MF-yyyy, Miscellaneous Investigations Maps = I-yyyy.
*For a full reference for USGS publications see: http://library.usgs.gov/