Aloha.
I’m trying to figure out how to extract attributed data from a shapefile so I can construct a cpt file (makecpt). I have successfully plotted a map from the shapefile using:
gmt psxy $OUTPUT_GMT $REGION $PROJECTION -W0.05+cf -aZ=KAcreFt -Crainbow.cpt -K > $OUTPUT_PS
but cannot figure out how to extract the KAcreFt attribute into a file that I can use to generate a colormap. I’ve tried gmt convert but seem to end up with all of the vertices of all of the polygons with the attribute value as the 3-rd column. Any advice is welcome.
Mahalo.
J.