grdfft ok.grd -F900000/900000/10000/10000 -V -Gfilt.grd

grdtrend gravi.grid -N9r -Tpolyn4.grid -Dresid.grid -V > trend.ps

grdgradient filt100.grid -Nt -A95 -Ggrad.grd 
grdimage filt100.grid -R -Jl -Igrad.grd -O -K -V -Cfilt100.cpt >>filt.ps


pstext -Jl-96./28.2/33/45/1:6000000 -R/-100.3/-90.8/28.2/34.5 -K -O <<END >>tri.ps
-94.05 30.54 11 0 1 2 TX
END
# plot scale
psscale -Ctri.cpt2 -D6.65/2.50/3.0/0.12 -O >>tri.ps

grd2cpt mydata.grd ?Crelief -L0/10000 -S0/200/20 > mydata.cpt



