Paleobathymetry data preparation How-To

You can download Dietmar Muller & Maria Seton (2008) data on paleobathymetry and oceanic crust age during last 140 Ma at http://www.earthbyte.org/Resources/palaeoagegrid2008.html

1. Extract contents of age_depth_bath_0.bz2 with any suitable archivier (like 7-zip).

2. Using Open Source tool set GMT (General Mapping Tools, http://gmt.soest.hawaii.edu/) ver. 4.5.9 64-bits (Windows 8) to process data.
Set table data delimiter:
gmtset.exe FIELD_DELIMITER=,

Extract three columns of data from table to make XYZ format ASCII file:
gmtconvert.exe age_depth_bath_0.xyadb -F0,1,2 -V > age_0.csv

Fore some reason, xyz2grd produce inverse projected grid (south-north is switched), so it is necessary to make nagative values of latitude in table:
gmtmath.exe -C1 -V age_0.csv NEG = age_0i.csv

Convert to netCDF grid of floating point values:
xyz2grd.exe age_0i.csv -Gage_0.flt=nf -N0 -Rd -I0.1 -V

Add header to this grid:
File age_0.hdr
ncols 3601
nrows 1801
xllcorner -198
yllcorner -90
cellsize 0.1
nodata_value 0
NODATA 0

3. Open in GIS application, set projection (geographic with datum WGS-1984), save in suitable format (GeoTiff), calculate statistics and pyramid layers.

For bathymetry data estract firth column instead of third from original table.
gmtconvert.exe age_depth_bath_0.xyadb -F0,1,2 -V > age_0.csv