Would this addon be useful?
https://grass.osgeo.org/grass78/manuals/addons/m.printws.html
On February 11, 2021 6:55:24 PM Chris Bartolomei via grass-user
<[email protected]> wrote:
Good morning Anna,
It took quite a while of trial and error but I worked out a method that
kindof works:
First off - unless someone says otherwise, you can't use the PNG driver
(d.mon) method to overlay more than one polygon vector. Sorry - it just
doesn't work. You CAN use the ps.map method - that works really well
generating the image however it by default assumes you are printing on an
A4 piece of paper so there's all sorts of white space. The image is
centered at the top of this fictional piece of paper. In your postscript
rules file you can use the "maploc" command to position the image elsewhere
on the page. This is necessary because the next trick changes the paper
dimensions but it assumes the origin is the lower left corner and therefore
clips anything that is above the new dimensions. Back to postscript
commands in the rules file first though ... the ps.map maploc command uses
inches (why?? it should be points) so an A4 page is 8.27" x 11.69" points
are 1/72 of an inch thus 595p x 842p - it also has a default 36p margin
(0.5 inch). You'll need those numbers later. maploc also lets you set the
size of your image box: maploc {x offset from left edge} {y offset from
top} {width of box} {height of box} Note: this is all done via a BASH
script with GRASS 7.4 on Linux (RHEL 7), not python. This is my postscript
rules file:
maploc 0.1 6.815 6.5 4.875 #468p x 351p map box moved down towards the
bottom of the page
# note that if you push it too far down to where the box would run off the
bottom, the image is
# resized to fit on the page so do some testing to come up with the correct
values
# also I found the computational region controls the aspect ratio so
although I say
# 6.5 x 4.875 with the above maploc command, I got a 6.5 x 3.8 inch box.
border y # add a border to the map frame (box)
color 81:81:81 # shade of gray
end # end the border controls
vareas admin_area # top vector layer to display
layer 1 # attribute table to use
rgbcolumn area_color # name of column holding R:G:B values to fill the polygons
color 153:153:153 #boundary color
end # end the admin_area controls
vareas Country # this is the bottom vectors to display
color 210:210:210 #boundary color
fcolor 153:153:153 #fill color for all polygons
end # end the Country controls
Here's the command to run to generate the postscript file:
ps.map input=$HOME/ps_rules.txt out=$HOME/color_admin.ps --overwrite
To convert the postscript to PNG I had to use ghostscript - there are other
tools you can use though.
gs -dSAFER -dBATCH -dNOPAUSE -sDEVICE=png16m -r300 -dTextAlphaBits=4
-dGraphicsAlphaBits=4 -dDEVICEWIDTHPOINTS=473 -dDEVICEHEIGHTPOINTS=276
-dFIXEDMEDIA -dPSFitPage -sOutputFile=$HOME/color_admin.png -c
"<</PageOffset [-34 78]>> setpagedevice" -f $HOME/color_admin.ps
So the above line needs some explaining
(http://www.ghostscript.com/doc/9.27/Use.htm) but in a nutshell, the
parameters to play with are first the Pageoffset [x y] values. They are in
points not inches ... 1/72 inch = 1 point ... remember the 1/2" margins?
the -34 gives me 2 points of white space to the left edge of the map frame,
the 78 I had to play with to push the map frame down to the right spot.
Next is the DEVICEWIDTHPOINTS and DEVICEHEIGHTPOINTS ... again in points
... this "trims" the paper to height and width ... set something then run
it and view the results. Adjust and run again until you get it correct.
It's a royal pain but it seems to work this way. It would sure be nice to
create a GRASS workspace file and just say "convert this workspace to an
image" with everything all laid out nicely - like Arc does exporting their
mxd map files...
I hope this helps someone !
:)
Chris
On Wednesday, February 10, 2021, 11:08:00 PM EST, Anna Petrášová
<[email protected]> wrote:
On Tue, Feb 9, 2021 at 4:41 PM Chris Bartolomei <[email protected]> wrote:
Hi Anna - thank you for the suggestion - I tried it but alas, still it only
outputs a single vector map (layer). I can get either the Country vector or
the admin_areas vector, but not both overlaid.
:(
Chris
I realized you are using both environmental variables and d.mon, that might
cause some issues, you use one or the other. So try to remove the lines
starting with d.mon.
Hope that helps,
Anna
On Tuesday, February 9, 2021, 1:20:52 PM EST, Anna Petrášová
<[email protected]> wrote:
Hi,
On Tue, Feb 9, 2021 at 10:25 AM Chris Bartolomei via grass-user
<[email protected]> wrote:
Good morning :)
I'm using GRASS 7.4.1 on a Linux cluster so I only have command-line
capability. I have two vector layers (a country boundary polygon and part
of an administrative area map - also polygons). I am trying to automate
creating a PNG file of the admin areas overlaying the country boundary
therefore all work has to be command-line (in a bash script). I've tried
this two ways - using the d.mon start=png method and also the ps.map method
as described below. The d.mon method appears to generate the image with
only one vector map (not both) and only colors the borders - it won't use
the fill_color setting. The ps.map method seems to work but assumes the
image is on a sheet of paper so there's a ton of extra white-space. I'd
like to use d.mon but I can use ps.map if someone could please let me know
how to export only the computational region without all the extra 'paper'
in the image. Here's my code:
g.region vector='Country'
export GRASS_RENDER_IMMEDIATE=png
export GRASS_RENDER_WIDTH=640
export GRASS_RENDER_HEIGHT=480
export GRASS_RENDER_TRANSPARENT=true
export GRASS_RENDER_TRUECOLOR=true
export GRASS_RENDER_FILE=$HOME/country_admin.png
export GRASS_RENDER_FILE_COMPRESSION=0
export GRASS_MESSAGE_FORMAT=plain
d.mon start=png
d.vect map=Country color=210:210:210 fill_color=153:153:153 display=shape
type=area
d.vect map=admin_area color=153:153:153 rgb_column=area_color display=shape
type=area
d.mon stop=png
This only produces a png with the last vector listed and only the borders
are colored with the rgb_column values.
I think you are missing GRASS_RENDER_FILE_READ=TRUE:
https://grass.osgeo.org/grass78/manuals/pngdriver.html
Regarding rgb_column, I am not sure, didn't have time to test.
Anna
If I do this without the d.mon start/stop lines ... i.e. relying on the
GRASS_RENDER_IMMEDIATE=png only, then only one vector map is converted to
png however it DOES do the color fill properly. With either above method
the png is the correct size.
Now using ps.map (same env variable set as above):
g.region vector='Country'
ps.map input=$HOME/ps_rules.txt out=$HOME/country_admin.ps --overwrite
where ps_rules.txt is:
border y
color 81:81:81
end
vareas admin_area
layer 1
rgbcolumn area_color
color 153:153:153
end
vareas Country
color 210:210:210
fcolor 153:153:153
end
We don't have pstopng but we do have ghostscript:
gs-dSAFER -dBATCH -dNOPAUSE -sDEVICE=png16m -dTextAlphaBits=4
-dGraphicsAlphaBits=4 -r300 -sOutputFile=$HOME/country_admin.png
$HOME/country_admin.ps
This creates the correct image (color fills, etc) but has white margins and
a lot of white space below the image like it is printed at the top of a
piece of paper.
does anyone have any idea how to create a png with multiple vector maps
overlaying each other (and not have the extra whitespace too)?
v/r
Chris
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