#
# prepare the holt strain map
#
awk '{print $3,$2,sqrt($4*$4+$5*$5+2*$6*$6) }' < ../holt/strain.dat  > secinv.gmt
xyz2grd secinv.gmt -Gjunk.grd -I0.1 `grdinfo grad.grd -I0.1/0.1` -NNaN
grdsample junk.grd  -Ql.1 -I.01 `grdinfo grad.grd -I0.1/0.1` -Gmask.grd
surface secinv.gmt -I.01 `grdinfo grad.grd -I0.1/0.1` -T.5 -Li0. -Gsurf.grd -V
grdmath surf.grd mask.grd OR = secinv.grd
grdsample secinv.grd `grdinfo grad.grd -I0.1/0.1` -I0.00833333/0.00833333 -F -Gholt_strain.grd
#
#  clean up
#
rm secinv.gmt secinv.grd  surf.grd mask.grd junk.grd