Hello list,
maybe among you some people deplore the absence of easy solution in
ps.map for line-end symbology, e.g. adding arrow heads to lines.
I used to fiddle with v.to.db and plpgsql functions from postgres
terminal. I found a faster and more portable one-line solution, detailed
here, fyi :
http://grasswiki.osgeo.org/wiki/Tips_and_Tricks#Compensate_the_lack_of_line_ends_symbology_in_ps.map
feel free to comment or correct !
Vincent.
Vincent wrote:
maybe among you some people deplore the absence of easy
solution in ps.map for line-end symbology, e.g. adding arrow
heads to lines.
(see also the vlines "linecap" instruction, for shape of the
end of the lines. Maybe there is a standard PostScript built-in
method for line end arrows already, but I don't know about it)
I used to fiddle with v.to.db
another self-hack possibility is to extract the start/end nodes
to a points file, then, maybe with the help of v.generalize,
find the trend direction (azimuth) at those two ends, and use
vpoints or point instruction there with appropriate rotation
angle. You'll probably need to make your own symbol, but that's
pretty easy.
Hamish
Hi Hamish,
Le dimanche 03 mars 2013 à 13:22 -0800, Hamish a écrit :
Vincent wrote:
> maybe among you some people deplore the absence of easy
> solution in ps.map for line-end symbology, e.g. adding arrow
> heads to lines.
my poor knowledge of C dissuaded me to investigate in this way...
another self-hack possibility is to extract the start/end nodes
to a points file, then, maybe with the help of v.generalize,
find the trend direction (azimuth) at those two ends, and use
vpoints or point instruction there with appropriate rotation
angle.
in a way (except recourse to v.generalize), this is what is performed in
my stack of commands.
You'll probably need to make your own symbol, but that's
pretty easy.
Here again it points to the power of ps.map. With a couple of postscript
lines you can do nearly whatever you want.
Yours,
Vincent