Associated data are given for each station used
to create the complete-Bouguer and isostatic gravity grids.
 This file is compressed ("zipped").

Number of records  = 36,618

Channel 1
 title = "sta_id"
 Integer value.  Because many of the original station ids were 
 not unique, the gravity stations were renumbered. 

Channel 2
 title = "Longitude"
 datum = NAD27, ellipsoid = Clarke 1866
 in degrees.minutes.decimal minutes 

Channel 3
 title = "Latitude"
 datum = NAD27, Ellipsoid = Clarke 1866
 in degrees.minutes.decimal minutes

Channel 4
 title = "X"
 projected x values, in meters.
 Lambert Conformal Conic, NAD27
 central meridian = -92° base latitude = 0°
 standard parallels = 33° and 45°

Channel 5
 title = "Y"
 projected x values, in meters.
 Lambert Conformal Conic, NAD27
 central meridian = -92° base latitude = 0°
 standard parallels = 33° and 45°

Channel 6
 title = "Station elevation"
 in feet 

Channel 7
 title = "Observed gravity"
 in milliGals
 
Channel 8
 title = "Inner terrain correction, zones 0-F"
 in milliGals

Channel 9
 title = "Outer terrain correction, zones G-O"
 in milliGals

Channel 10
 title = "Free air gravity anomaly (1967)"
 in milliGals

Channel 11
 title = "Complete Bouguer gravity anomaly (1967) at 2.67 g/cc"
 in milliGals

Channel 12
 title = "Isostatic correction - value of isostatic root"
 root depth = 20 km, density contrast = 0.3 g/cm3
 in milliGals
 
Channel 13
 title = "Isostatic gravity anomaly"
 Bouguer gravity minus Isostatic Correction
 in milliGals