[GRASS-user] d.rast.arrows in high quality plot

[Nicolas Pérenne]

Hi Niklas, 

Same for me: the PNG driver draws thinner and thinner arrows when you
increase the resolution. If you lower the resolution it's okay though. 

If you do need such a high resolution (for a poster?), you might try the
CAIRO driver (g.manual displaydrivers) which behaves quite differently
when producing PNGs. Arrows are drawn with a thicker pen indeed (even at
high pixel resolution) but you might be surprised by the raster
rendering... and files get very large. 

Nicolas

Le mardi 02 novembre 2010 à 16:12 +0100, Niklas Neckel a écrit : 
> Dear all,
> 
> I'm trying to plot arrows, representing length proportional to magnitude in a printable high resolution map (with d.rast.arrows). Here is what I tried:     
> 
> #!/bin/sh
> export GRASS_WIDTH=10000 
> export GRASS_HEIGHT=10000
> export GRASS_PNGFILE=testpng.png
> export GRASS_PNG_COMPRESSION=0
> #export GRASS_RENDER_IMMEDIATE=TRUE
> export GRASS_TRUECOLOR=TRUE
> g.region fig_arrows
> d.mon start=PNG
> d.rast map=background at PERMANENT 
> d.rast map=Magnitude_map at PERMANENT 
> d.rast.arrow map=Direction_map at PERMANENT type=compass  arrow_color=black grid_color=none  x_color=black unknown_color=red  skip=12 scale=20 magnitude_map=Magnitude_map at PERMANENT
> d.mon stop=PNG
> eog $GRASS_PNGFILE&
> 
> Unfortunately the plotted arrows are quite slim now... is there another solution to achieve this goal?
> 
> Many thanks,
> 
> Niklas
> 
>