Hi Chris,
For me, the following works with the current stable GRASS GIS (7.8.5)
and using maps from the NC demo data set:
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_COMPRESSION=0
export GRASS_MESSAGE_FORMAT=plain
export GRASS_RENDER_FILE_READ=TRUE
g.region vect=census_wake2000
d.vect map=census_wake2000@PERMANENT fill_color=none
d.vect map=roadsmajor@PERMANENT color=255:0:0:255
d.vect map=schools_wake@PERMANENT fill_color=0:128:0:255
icon=basic/circle size=10
I attach a small thumbnail of the resulting PNG file.
Moritz
On 11/02/21 18:54, Chris Bartolomei via grass-user 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
<kratocha...@gmail.com> wrote:
On Tue, Feb 9, 2021 at 4:41 PM Chris Bartolomei <surf...@yahoo.com
<mailto:surf...@yahoo.com>> 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
<kratocha...@gmail.com <mailto:kratocha...@gmail.com>> wrote:
Hi,
On Tue, Feb 9, 2021 at 10:25 AM Chris Bartolomei via grass-user
<grass-user@lists.osgeo.org <mailto:grass-user@lists.osgeo.org>> 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
<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 likeit 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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