Re: ps2raster offset with world file

Brent Wood <[email protected]>
Newsgroups gmane.comp.gis.gmt.user
Message-ID <[email protected]>
Thanks Joaquim,

All the text & scale content drawn in the map lie within the map extent in the figure defined by the -R parameter, so there should not be ANY content outside the map area. 

If I comment out the pstext & psscale commands, the map is unchanged. I also need to try another mapping tool to check that the issue is with the maps rather than the QGIS overlay of the layers.


The error, from the .gmtdefaults4 file:

initial state: 
BASEMAP_TYPE       = plain
FRAME_PEN          = 1.25p
 
after running "gmtset BASEMAP_TYPE inside"

BASEMAP_TYPE       = FRAME_PEN      = 1.25p 

I have not tried manually editing the .gmtdefaults4 file to set BASEMAP_TYPE to inside


Cheers,

   Brent     




________________________________
 From: Joaquim Luis <[email protected]>
To: [email protected] 
Sent: Sunday, February 2, 2014 11:27 AM
Subject: Re: [GMT-HELP] ps2raster offset with world file
 


Brent,

It must be pscale. For the same reason we must use
    BASEMAP_TYPE=inside we cannot have other drawings outside the map
    frame. This will trick the coordinates-from-pixels algorithm that
    assumes all pixels of the rasterization belong to the map.

and yes, you need to repeat the inline setting for all the commands.
    The idea of the inline is that it works only on the command where it
    is invoked.

What was the error when you tried to default basemap type to
    "INSIDE"?

Joaquim


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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