[GRASS-user] measuring distance along a line

[Hamish]

Ronja Düffel wrote:
> is there a possibility to measure distance along a line in grass?

yes.

> I have a map of a river system and I have points (given by Northing
> and Easting) where rivers con- or diverge. Now I would like know the
> distance between those points, measured along the course of the
> river. Is there a possibility to do that in grass without having to
> measure the distance by hand (i.e. using the measuring tool in the
> display window)?


Beware that this is a fractal problem and the answer is dubious!


maybe something like:

v.clean in=rivers out=river_lines tool=break
v.db.addcol river_lines column="seg_length DOUBLE PRECISION"
v.to.db river_lines option=length column=seg_length units=me

d.vect river_lines disp=shape,attr attrcol=seg_length


you might also look at v.segment and v.lrs.*


Hamish