Downsampling of Topographic Data
This can be done using the following script: downsample-gmt.sh
Examples:
./downsample-gmt.sh etopo1.xyz > output.xyz ./downsample-gmt.sh etopo1.grd > output.xyz
It uses GMT's grdsample program; for that, it converts the data into the *.grd format (or omits that step if a grid file is given). For the conversion to *.grd a gridspacing of 1 arc minute is assumed (= like ETOPO1).