[Freegis-list] change vector line direction

[Markus Neteler]

On Thu, Apr 27, 2006 at 10:15:38PM +0200, Maciek Sieczka wrote:
> Hi!
> 
> I've been looking for a software which can change vector line direction
> attribute. A thing that ArcInfo has been a long time able to do...
> 
> Really, any hints, for any format and platform, please.
> 
> Thanks,

Maciek,

I guess that you are GRASS user :-)
You could export lines with v.out.ascii and then revert the
vertices order with the UN*X tool
      rev - reverse lines of a file
and a bit of script magic. Then v.in.ascii and voila'.

Untested:
A better solution is to use v.example [1] and just invert the
reading order (descending instead of ascending) for each
line and write it out.

But I am not sure why you need this. GRASS is supporting
forward *and* backward direction. So you could just modify
the line attributes. I have added some screenshots here:

 http://grass.itc.it/grass61/screenshots/network.php

older ones are here (at page bottom):
 http://grass.itc.it/grass60/screenshots/vector.php


Markus

[1] grass61/doc/vector/v.example/