|OFR 99–0557: Data Format and Digitizing Technique for XYZ Files|
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Longitude, Latitude, Magnetic Field Value - (2f11.4, f8.1)
Longitude - decimal degrees
Latitude - decimal degrees
Magnetic Field Value - nanoTesla or gamma
NOTE: longitude and latitude are defined to four decimal places (10 meter resolution) because this is the most reasonable accuracy that can be standardized for the variety and scaling of the original maps.
*.JPG images of the data were created using a Geographic Coordinate (longitude, latitude) System and the Clarke 1866 datum.
The procedure used to digitize the XYZ files was one of the following three methods:1) flight line/contour line crossing and interpolation of values along the flight lines.
2) flight line/contour line crossing and inflection points of contour lines between flight lines.
3) contour lines without regard to flight line positions.
This report is preliminary and has not been reviewed for conformity with U.S. Geological Survey editorial Standards. Use of brand names is for descriptive purposes and does not constitute endorsement by the U.S. Geological Survey.
Last modified 9/14/1999.
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