Polygons on Topograhy map

Hello all,

I have polygons to plot on GMT. I would like to put these polygons top of topography but also I would like to see topography relief under the polygon color. I am doing this right now only by making one of them, either topography or polygons, with giving some transparency but It looks faded.

What I would like to do is put these polygons top of a topography without giving transparency but rather its own (polygon) color to topography relief within that specific polygon which cover that section of topography.

Is there any way to do this on GMT 5.4?

best wishes,

If you want to maintain the polygon’s color the only way of giving an idea of relief is with the shading illumination. You would compute first an image with the polygons colors and drape it on topography with grdview -G. Use also -I to get the sense of relief

Bad idea. (and before you say it. Everybody can have an updated GMT version)

Dear Joaquim,

thank you for your reply, I have more than one polygon and they cover different areas on the topography, I am a bit confused about how could I give different polygon colors on topography?

if it is exist in the GMT examples, would you direct me which one should I concentrate to illustrate it?

Multi-segments files let us add a -G into each of the segments header. So you can use psxy to make an image (with no frame) that you later use to drape with grdview.

But are you sure the procedure shown in https://docs.generic-mapping-tools.org/dev/gallery/ex34.html is not good enough? Because it’s much simpler.

Yes, this is a quite close what I would like plot,

thanks a lot