Gravity Database Descriptions

WGS84 datum for all datasets  

Ground Survey:

1. LAT: latitude in degrees
2. LONG: longitude in degrees
3. afghan_x: projected x coordinates in meters (afghan_tm projection)
4. afghan_y: projected y coordinates in meters
5. GRAV_OBS: observed gravity
6. Elevation: ground elevation at station
7. FAA: free air anomaly
8. simple_boug: simple Bouguer anomaly
9. tc: terrain correction (895 meter to 167000 meter)
10. complete_boug: complete Bouguer anomaly


Airborne Survey: (elevations = ellipsoid height since using WGS84)

0.   line: L- flight line, T- tie line, D- random line
1. latitude: latitude in degrees
2. longitude: longitude in degrees
3. xTM: projected x coordinates in meters (afghan_tm projection)
4. yTM: projected y coordinates in meters
5. GPS_Elevation: sensor elevation
6. SRTM_90m: ground elevation from 90 meter SRTM dataset
7. terrain_clear: terrain clearance (GPS_Elevation - SRTM_90m)
8. nrl_faa: free air anomaly values at original sensor height, from NRL
9.   faa_at 7km: free air anomalies draped at 7000 meter above ground surface
10.  parker: Parker model calculation at 8000 meters elevation, based on 1000 meter DEM
11.  parker_7km: Parker model draped at  7000 meter above ground surface
12.  parker_7km_filt: Parker_7000 meter low-pass filtered to match frequency content of FAA
13.  cba: complete Bouguer gravity anomaly (faa_at7km - parker_7km_filt)