ps2raster offset with world file

Hi,

I have a problem with a png + worldfile image by ps2raster georeferencing correctly. I figured I'd ask here before submitting a bug report in case I'm the bug...

The map is generated by a script - as below. A small part of the output image is attached. The red coastline shows the actual vector coastline opened in QGIS, overlayed on the GMT image which includes the same (rendered/pixellated)coastline.

As shown in the image, the ps2raster coastline appears to be offset from the vector coastline. About a 1km offset in real world distances. This offset is worse towards the top of the map.


I note that I can't set the default basemap type to "INSIDE" - this results in an error - and using the inline approach as for the psbasemap command below does not reset the gmtdefaults4 file - this remains set to "plain". Do I need to include the inline setting for all the commands?


Any advice appreciated...

Brent Wood



 # generate lat/lon png with world file
  psbasemap -R$REG -JX5i -P -K -B/::wesn --BASEMAP_TYPE=inside > $PS2
  psxy nz_shelf.gmt -R$REG -JX -W1 -m -K -O -G210/240/245 >> $PS2
  psxy nz_50m.gmt -R -JX -W1 -m -O -K -G230/255/255 -W1/230/255/255 >> $PS2
  # psxy nz_coast.gmt -R -JX -W1 -m -O -K -G200 >> $PS2
 
  # overlay with specific data
  echo "175 -52.5 10 0 1 ML Species/year" | pstext -R -JX -W -O -K >> $PS2 
  echo "175 -53.2 10 0 1 ML All spp   $YR" | pstext -R -JX -W -O -K >> $PS2 

  echo "adding scale"
  psscale -D10/3.2/3.0/0.3 -C$CPT -A -L -O -K -B::/:: >> $PS2
  echo "175.5 -45.1 10 0 1 ML Tows/cell" | pstext -R -JX -W -O -K >> $PS2 

  #plot cells
  echo "plotting cells"
  # with clip path
  psclip nz_shelf.gmt -R -J -m -O -K >> $PS2
  cat $FILE | psxy -R -JX -O -K -Ss$SYM_SIZE -C$CPT >> $PS2
  psclip -C -O -K >> $PS2

  # draw coast
  psxy nz_coast.gmt -R -JX -W1 -m -O -G200 >> $PS2
  
  # generate png with world file
  ps2raster -Tg -Au -E600 -W $PS2

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