Hi!
My name is Ezequiel D. Antokoletz. I am a PhD student from Argentina.
First of all, thank you very much for providing GMT for users, it is a very useful tool! I am writing you as I might find an issue with grdgradient under Windows x64 GMT v6.1.1. When trying to build the out_gridfile with the option -G, no file is created. I have tried with several extensions and none of them is working. When going back to GMT v6.0.0 no problem appears.
Best regards and thank you very much,
Ezequiel.
Hi @eantokoletz, welcome to the forum!
Would you mind posting the code in question? Without details it is a bit difficult to help.
Hi @KristofKoch!
Thanks for your quick response! Yes, sure!
gmt grdgradient srtm3_LP2014.grd -A0/0/1 -GILUM.grd -Ne0.6 -V
Unfortunately, I cannot provide the source file “srtm3_LP2014.grd” but it is a grid topography file.
Thanks!
I think that it is wrong. -A accept only one or two values. Maybe this solved your problem.
https://docs.generic-mapping-tools.org/latest/grdgradient.html
Thanks! I will test it 
I’m afraid that’s the key of the problem. What is the output of?
gmt grdgradient srtm3_LP2014.grd -A0/0/1 -GILUM.grd -Ne0.6 -Vd
Note, the -A0/0/1 though wrong is not fatal.
Hi Joaquim,
Yes, that is clear, I do have the srtm3_LP2014.grd file. I cannot make it available through the forum. The problem is that no output file is created running the line under v6.1.1 in Windows.
Yes, -A is not fatal.
Hi @eantokoletz,
please note that the command @Joaquim posted has -Vd at the end. That means executing this command will print a lot of debugging messages to your terminal (more info on the -V option).
Post that output here and it will help the more knowledgeable people here to understand what’s going wrong.
Thanks for the comments. I have tested it again on another machine and the problem is solved. Probably it is a problem with the original machine I used. Thanks anyway for the help!
Nearly impossible but if it’s solved, ok.