Hi Nicolas,
The R-Ecosystem is definately worth to be relearned. Especially with
introduction of simple features, the sf-package, in combination with the
tidyverse, vector and data handling in R became much easier. My once
hundreds of lines of code condensed to some dozends.
And no, I have nothing to do with that package, I just stumbled upon it
after reading about your case and a quick search for tools in R for such
a use case.
Good luck,
Bernd
Am 16.04.19 um 15:54 schrieb Nicolas Cadieux:
Hi Bernd,
R is one of those softwares I need to relearn every second year!! I just don’t
use it enough but the package look promising. Did you create that particular
package?
Nicolas
Le 16 avr. 2019 à 09:43, Bernd Vogelgesang <[email protected]> a écrit :
Hi Nicolas,
I'm neither familiar with networks nor rivers nor python, but i made
myself befriended with R in the last years. I never used it from inside
QGIS but "standalone" with R studio.
As it's a real data-cruncher and easy to debug the code line by line, I
use R for all "more complex" situations where you have to find your way
by trial-and-error to the final solution.
I can just recommend to have a look at this
https://cran.r-project.org/web/packages/riverdist/vignettes/riverdist_vignette.html
page, as it looks quite promising to what you want to achieve (from
quick read)
In case you are interested in trying that route, just contact me in case
of questions / assistance etc.
Cheers,
Bernd
Am 16.04.19 um 06:13 schrieb Nicolas Cadieux:
Hi again,
Thanks Nyall, Micha and Alessandro for your help on correcting the
river flow directions. I am still working on it but you gave me the
right tools. The next step of my project will be to use my river flow
network and find the shortest path between THOUSANDS of points (so I
will need to batch it or script it in Python).
It gets complicated as I will need to calculate the total trip for
each shortest path (easy) and then the percentage of that trip that
was made going downstream (the rest being the upstream trip). I don't
know if there is a tool for that? If not, my goal was to use the
shortest path lines to do a spatial query on my network and figure
things from there.
Anyways, I don't have much experience with networks so that's what I
need to figure out. I also mostly use Python outside of QGIS so my
questions are basic for now. I see that many plugins have been
incorporated in Processing but the Shortest path (point to point)
builds a new graph every time. I figure I need to build a graph but
that does not seem to be available in QGIS 3.6.
I found this
https://docs.qgis.org/testing/en/docs/pyqgis_developer_cookbook/network_analysis.html#building-a-graph
but the very first command "from qgis.networkanalysis import *" in the
QGIS python console indicates "ModuleNotFoundError: No module named
'qgis.networkanalysis'".
Question 1: Is the qgis.networkanalysis module being replaced or
renamed in QGIS 3.6 (OSGEO4w64 intall
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