[R-sig-Geo] Distance calculating between points according to a river network

[Tristan Bourgeois]

Hi Mirza,

Thanks for your quick answer.

Actually I don't want to calculate distance between a point and the next
downstream one.
For example, if there are 4 sewage plant on a river and 7 measurment
stations,I want the distance between each sewage plant and each station.
(water pollution dispersion calculation).
So the flow direction is not that important in my case. The difficulty is
to get the distance between a point and another one following the river
polyline.

In your case, you can add a raster layer with elevation values ans extract
the elevation  for each point of your layer.  Then, for each polyline it is
possible to define a flow direction.
Hope it will help you.




2017-01-25 11:57 GMT+01:00 Mirza Cengic <mirzaceng at gmail.com>:

> Hi Tristan,
>
> I recently had to do something similar (calculating distance to the next
> downstream point), and I was not able to find a solution with R that would
> deal with the direction of the flow. Perhaps someone who has deeper
> understanding of packages such as iGraph etc. might be able to find a
> solution, but I wasn't.
> I solved the problem with ArcMap, using HydroTools extension, where you
> need to define a geometric network that has a direction, and then the
> calculation is pretty straightforward with HydroTools (let me know if you
> need more info).
> I would prefer to have a scripted solution in an open-source software, but
> this worked for me in any case. If anyone has a better way for solving
> this, I would love to see how!
>
> Cheers,
> Mirza.
>



-- 
Tristan Bourgeois

	[[alternative HTML version deleted]]