[GRASS-dev] Re: v.net.path

Markus Neteler neteler at itc.it
Fri May 4 04:10:14 EDT 2007


On Thu, May 03, 2007 at 01:24:33PM +0200, Markus Neteler wrote:
> On Thu, May 03, 2007 at 08:32:00PM +1200, Hamish wrote:
...
> > v.net.path:
> > "Shortest path from two digitized nodes" example
> > also try:
> >   d.path -b roads coor="601653.5,4922869.2","593330.8,4924096.6"
> > and
> >   d.path -b myroads_net coor="601653.5,4922869.2","593330.8,4924096.6" \
>            afcol=forward hcolor=green
> 
> How cool, I didn't realize this -b flag so far.
> The difference is striking. I am not really sure about the second one.

OK, my mistake - the column should contain *costs*. That might be
the inverse of the speed limit, not the speed limit itself:

e.g.
# define traveling costs as inverse of speed limit:
v.db.update myroads col=forward val=1/50

I have update the example in CVS. Please suggest if you have better
ideas.

Markus




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