I’m struggling to try to understand how to properly use perspective view (-p) option in GMT5. I’m mainly facing two issues that I’d appreciate some hints on how to handle.
Using the -p option in combination with pscoast shifts the plot in vertically for azimuth not equal to 180 which of course can be compensated for by use of -Y option but it is not clear to me how to properly compute what shift to use. Any hints here would be appreciated (perhaps the shift could be avoided).
The second issue is when combining pscoast with psxyz as it seems that I cannot figure out how to place the map produced by pscoast at Z=0, thus the markers plotted by psxyz do not appear in the proper place but again appear shifted vertically (again this could be compensated for by us of -Y if I knew how to compute the shift, but it seems that this should not be the proper solution).
As an example, the following commands demonstrate both issues:
pscoast $J $R -Ba2f1WESN -A100 -G255/255/204 -S204/229/255 $p -Y-12 -Dh -W1 -N1 -P -K > test.ps
psxyz -J -JZ5 $R/0/8 $p -Ss0.4 -W4,red -O << EOF >> test.ps
15 61 0
Note the use of -Y-12 in the call to pscoast to compensate for the vertical shift. In the resulting plot the marker created by the call to psxyz is clearly shifted vertically. I noted in the documentation that /zlevel can be added to option -p but this does not solve the shift of the psxyz marker so probably I’m miss-understanding how to use this