Plotting map of Hawaii with text

Q&A
1

Im having trouble plotting Hawaii while also including text at the top and bottom without causing the state to be “squished”. What am I doing wrong?

I have adjusted the region bounds but that does not seem to help. I only have basic knowledge of GMT but it seems like there is a simple solution. Any help is appreciated.

Im using GMT6.4.0

Without the text

#!/bin/csh

setenv region -Rg-159.8/-154.7/18/23
setenv projection "-Jx2.5"
setenv pagecolor 148/148/148
gmt psxy $region $projection --PS_MEDIA=a4 --PS_PAGE_COLOR=148/148/148 $polyfile -W0.4p,0/0/0 -K > $outfile.ps
gmt psxy $projection $region $polyfile -W0.4p,0/0/0 -Glightbrown -O >> $outfile.ps
convert -trim -flatten -density 300 -rotate 90 -geometry 650x475! +repage $outfile.ps $outfile.png

With the text

#!/bin/csh

setenv region -Rg-159.8/-154.7/18/23
setenv projection "-Jx2.5"
setenv pagecolor 148/148/148
gmt psxy $region $projection --PS_MEDIA=a4 --PS_PAGE_COLOR=148/148/148 $polyfile -W0.4p,0/0/0 -K > $outfile.ps
gmt psxy $projection $region $polyfile -W0.4p,0/0/0 -Glightbrown -O >> $outfile.ps
echo "-157.5 22.5 TOP" | gmt pstext $region $projection -F+f11p,21 -N -O -K >> $outfile.ps
echo "-157.5 18.5 BOTTOM" | gmt pstext $region $projection -F+f11p,21 -N -O >> $outfile.ps
convert -trim -flatten -density 300 -rotate 90 -geometry 650x475! +repage $outfile.ps $outfile.png

test

test-topbottom

2

Don’t use convert (I don’t know what it is doing. Use psconvert and add a -Ba to see the coordinates where text is being placed.

3

This is not good either. Drop the ‘g’

4

pstext also expects to be told the text angle and justification
use eg -F+a0+jTC
or pipe them to pstext as the third and fourth column and use -F+a+j

5

convert is part of imagemagick

6

not according to the docs, unless +a and +j are present as part of -F but without an angle and justification specification.

angle is probably not needed here, but +j and +c help with text placement that is like “top center” or “bottom left” and even +t. like:

gmt pstext -R-159.8/-154.7/18/23 -Jx2.5 -F+cBC+jTC+f11p,21+tBOTTOM -Dj0.1c -Bltrb -P -N > outfile.ps
gmt psconvert outfile.ps -Tg -A

-F+cBC+jBC is for label placement inside the frame (drawn just for illustration), +cBC+jTC places the label outside the frame so -N must be present in this case. -Dj adds offset from so the label does not overlap with the frame if there is one. -P enables portrait orientation, so no need to rotate the map afterwards.

outfile
outfile1515×1528 12.1 KB

7

Thanks for the tips! The imagemagick convert was causing the distortion issue.
I was able to get a proper image using

gmt psconvert $outfile.ps -A -I+s10c -Tg

However, the geometry of the image needs to be 650x475.
Its currently 1536x1479

I do not see an specific examples in the help pages or anywhere else on how to do this but it seems I need to use either the -A or -I option in psconvert. Any suggestions on how to get the desired geometry?

8

GMT figures use physical dimensions, not pixels. You may make computations using the -E or -I+S options to get the desired size in pixels. Or use an external program to do that resizing.

9

well topic starter started with using imagemagick’s convert in the topic

except that imagemagick needs to be configured to preserve aspect ratio and to fill in margins as needed.