There is a strange line on my map, is it a bug from grdimage?

Hi, I found a strange line on my map. Is it a bug on grdimage? I used grdgradient and grdimage on my code. I also tried to convert it to png, jpg, and pdf, but the line still remains. Can anyone help me? Thank you

Are you able to create a minimal working exmaple (see pr. 4 here) and post the code?

Oh ya sorry

I use topography and bathymetry data from gebco. Here is the code

gmt begin biak png
gmt grdgradient gebco_indojepang.grd -A0 -Nt -Giluminasi.nc
gmt makecpt -Cgebco
gmt psbasemap -JM7 -R131.0065/141.3786/-4.0658/0.9679 -Ba2f1 --MAP_FRAME_TYPE=plain --MAP_FRAME_PEN=1p --FONT_ANNOT_PRIMARY=4p --MAP_TICK_LENGTH_PRIMARY=3p --FORMAT_GEO_MAP=ddd.xF
gmt grdimage gebco_indojepang.grd -Iiluminasi.nc -JM
gmt coast -W0.1p -Dh
gmt psxy Molucca_fault.gmt -Wblack
gmt psxy trench.gmt -W0.3 -Sf0.3/0.03+l+t -Gblack
gmt end show

Thanks.

I’m not getting that line. Assuming it’s not caused by Molucca_fault.gmt or trench.gmt; I don’t have those. I also use @earth_relief_10m instead of your gebco_indojepang.grd.

gmt begin biak png
  gmt grdgradient @earth_relief_10m -A0 -Nt -Giluminasi.nc
  gmt makecpt -Cgebco
  gmt psbasemap -JM7 -R131.0065/141.3786/-4.0658/0.9679 -Ba2f1 --MAP_FRAME_TYPE=plain --MAP_FRAME_PEN=1p --FONT_ANNOT_PRIMARY=4p --MAP_TICK_LENGTH_PRIMARY=3p --FORMAT_GEO_MAP=ddd.xF
  gmt grdimage @earth_relief_10m -Iiluminasi.nc -JM
  gmt coast -W0.1p -Dh
gmt end show

Which version are you using?

After I see your picture and there is no strange line, I assume that there is an error with my bathymetry data. I try to open it on qgis and I find that the gebco_indojepang.grd data is error. I think it is because of the converting process from tiff to .grd. Then I try to redownload the same gebco data and finally, there is no strange line. Thank you for your help

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Very good!

Remember that gmt very conveniently offers remote datasets; see e.g. GMT Remote Datasets Documentation (that’s the @earth_relief_10m in my code).

ok thx, I will try it