[GRASSLIST:5237] Re: vector question

Radim Blazek blazek at itc.it
Thu Dec 19 07:27:26 EST 2002


On Thursday 19 December 2002 12:31 am, Ivan Marchesini wrote:
> Hello to all
>
> have you idea how I can do a unusual thing with grass???
> I would like to draw a vector polyline (not straigth) using v.digit and
> then to obtain some straigth line, regulary spaced, perpendicular to the
> polyline..... like this:           --|----|----|----|----|--
> the problem is that I need a large number of these perpendiculars and I
> would like to obtain them automatically after drawed the polyline......  
> :-)
>
> I know it is a unusual question but I hope someone can help me......
> thank you....
>
> Bye Ivan

Something like http://mpa.itc.it/radim/g51/lrs1.png ?

I have some first modules for Linear reference system (LRS) in GRASS:
v.lrs.create - create LRS from lines and points (milestones)
v.lrs.segment - create events (points/segments) for existing LRS
                and given distances
v.lrs.stationing - create stationing + labels along the lines for
                   existing LRS

If you don't need real LRS (i.e. you don't need to work with some
reference system used in real world like kilometers along the roads)
you could modify (simplify) v.lrs.stationing.
It is not yet in CVS but if you are interested I can put it on the Web.

Radim




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