Issue with Overlapping GMT grdimage Plot

Q&A
1

Dear GMT Community,

I am currently facing an issue while plotting multiple GMT grdimage files in a single plot. I have two .DAT files, each of which I converted into .grd files and then attempted to visualize using the gmt grdimage command. However, I have observed that only the last grd plot is visible in the final plot, as it overlaps the previous grd file.

Upon further investigation, I suspect the issue might be related to zeros being plotted as white in the color palette (.cpt) files, leading to the overlap. I would appreciate any guidance on how to resolve this issue and successfully display both grd files in the final plot.

I have attached the .DAT files and the gmt script for reference.

Thank you in advance for your assistance.
grdimage_plot.txt (1.1 KB)
BEL.DAT (250.2 KB) GHU.DAT (250.3 KB)gridplot.ps (409.5 KB)

2

you need to join your grids before plotting, otherwise you plot one on top of the other and can only see the last grid displayed as you suspected.

as your grid regions match, data don’t overlap, and the “empty” value is zero, you can sum the grids and plot the sum:
gmt grdmath BEL.grd GHU.grd ADD = BEL+GHU.grd
then plot the BEL+GHU.grd

3

If you really intend that your zeros should be transparent then you need to take some action along those lines, otherwise you are just plotting on top of the other and blocking it out. Or do as @mkononets says.

4

Thank you @mkononets