calculating slope and azimuth 

  使うコマンド  grdgradient, grdmath



bash スクリプト例
#  calculate azimth/slope and plot

# parameter setting
region=137:40/137:55/16:40/17           # grid region east/west/south/north
proj=M10                                # map projection and scale
ticks=f1ma10m                            # boundary tick info
frame1=WSne+tazimuth                     # boundary frame info
frame2=WSne+tslope                     # boundary frame info
grdfile=area.neargrd                    # bathymetry grid file
azimfile=area_azim.grd                  # output azimuth file (degree)
slopefile=area_slope.grd                   # output slope in azimthal direction (degree)
cptfile_azim=azim.cpt                  # color table for azimth  (manulally created)
climit=0/50/5                           # color limit for slope
cptfile_slope=slope.cpt                 # color table for slope
psfile=area_analysis.ps                  # output postscript file name
#
# calculate azimth / slope
#gmt grdgradient $grdfile -Stmpslope.grd -D -M -G$azimfile -V
#gmt grdmath tmpslope.grd ATAN PI DIV 180 MUL = $slopefile
#
# plot
#
#gmt makecpt -Cgray -T$climit -I > $cptfile_slope
#
gmt grdimage $azimfile -R$region -J$proj -C$cptfile_azim -K -V > $psfile
gmt psscale -D5/-1/10/0.5h -B45 -C$cptfile_azim -K -O  >> $psfile
gmt psbasemap -R$region -J$proj -B$ticks -B$frame1 -K -O -V >> $psfile
gmt grdimage $slopefile -R$region -J$proj -C$cptfile_slope -K -O -X12 >> $psfile
gmt psscale -D5/-1/10/0.5h -B10 -C$cptfile_slope -K -O  >> $psfile
gmt psbasemap -R$region -J$proj -B$ticks -B$frame2 -O  -V >> $psfile
#



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