Thank you Ujaval, I'll try this as well. Would you suggest to run it like a batch process on all origin-destination pairs, as the one suggested at point 22 of the tutorial?
Thanks a lot again and have a good weekend! Francesca Il giorno ven 6 mag 2022 alle ore 16:47 Ujaval Gandhi < [email protected]> ha scritto: > You need to do Distance Matrix. See > https://www.qgistutorials.com/en/docs/3/origin_destination_matrix.html > > On Fri, 6 May 2022 at 7:33 PM, Francesca Parente via Qgis-user < > [email protected]> wrote: > >> Thank you very much indeed Nicolas, for your inputs and all the suggested >> materials! >> I have 50 targets and 532 origins. My goal is to define where is best to >> go within the 50 destinations for each starting point - given the actual >> range of choices though, so I'm not sure that running a batch one-to-many >> would take into account all the variables properly as a many-to-many would >> do. In the absence of a specific modelling, also some second best could >> work. >> >> I understand that your upstream-downstream-Dijkstra script is suitable >> for layer-to-layer indeed and I'm trying to run it, but at the >>> import >> geopandas as gpd<< line I got the following error message: >> >> >> >> >> >> >> >> *Traceback (most recent call last): File >> "C:\OSGEO4~1\apps\Python37\lib\code.py", line 90, in runcode exec(code, >> self.locals) File "<input>", line 1, in <module> File >> "C:/OSGEO4~1/apps/qgis/./python\qgis\utils.py", line 799, in _import mod >> = _builtin_import(name, globals, locals, fromlist, level)* >> *ModuleNotFoundError: No module named 'geopandas'* >> >> I've been following your tutorial, but I admit I'm not quite familiar >> with py. I've gone through the remaining import coding and it seems >> working, but I'm not sure the "geopandas" module is needed or not to >> properly complete the script. >> >> Thanks again!! >> Best, >> Francesca >> >> Il giorno gio 5 mag 2022 alle ore 22:28 Nicolas Cadieux < >> [email protected]> ha scritto: >> >>> Hi, >>> >>> How many shortest path calculations are you looking at? You could >>> probably do a all pairs shortest path dijkstra and filter the results. You >>> could batch multiple one to many (point to layers) In QGIS using the >>> processing plug-in. >>> >>> I did create an algorithm using networkX that could be modified to work >>> with two input layers. This could be useful if QGIS is not fast enough or >>> if you have too many routes to calculate. You will find it in the links >>> below. Keep in mind this algorithm was for rivers therefore you have no >>> trafic rules. This would need more work. >>> >>> You will also find an article we wrote in Data that may help. If you >>> have trouble with the network, look in the QGIS hub for the models. Look >>> for the 3 “fix directional networks models”. >>> >>> I added a few YouTube videos I made. >>> >>> https://gitlab.com/njacadieux/upstream_downstream_shortests_path_dijkstra >>> <https://www.mdpi.com/2306-5729/5/1/8> >>> >>> https://www.mdpi.com/2306-5729/5/1/8 >>> >>> https://plugins.qgis.org/models/ >>> >>> https://youtu.be/v61PafSByvM >>> >>> https://youtu.be/qQrHcKtmr3o >>> >>> >>> Nicolas Cadieux >>> https://gitlab.com/njacadieux >>> >>> Le 5 mai 2022 à 10:38, Francesca Parente via Qgis-user < >>> [email protected]> a écrit : >>> >>> >>> Hello everyone, >>> >>> I'd need to identify optimal destinations (within a point layer of >>> geolocated facilities) for each territory of a given set of possible >>> origins. >>> I already calculated a distance matrix between the two point-layers, and >>> also applied the distance-to-nearest-hub tool to generate a string layer >>> and identify the optimal facilities. >>> But I'd like to obtain a more realistic estimate, accounting for the >>> roads network (and ideally their travel times). With quite a few issues, I >>> finally managed to import an OSM road network from download.geofabrik.de >>> (in order to cover my area of interest, I had to merge two different >>> vectors fo Center and Southern Italy and then extract a focus spot in >>> between the two and save it as a lighter layer, otherwise it also took an >>> eternity to run every analysis). >>> >>> So now my question would be: is there a tool to perform a layer-to-layer >>> shortest-path analysis that takes it into account? >>> All that I could find was either point-to-point or >>> layer-to-point/point-to-layer (I looked also at built-in network analysis >>> tool and Qneat3 plugin). >>> >>> Any kind of inputs and suggestions will be more than welcome! >>> Thanks a lot for your support and have a good day, >>> Francesca >>> >>> -- >>> ---------------------------- >>> Francesca Parente >>> >>> _ SESS Euro PhD >>> <https://phd.uniroma1.it/web/FRANCESCA-PARENTE_nT1602922_IT.aspx> in >>> SocioEconomic and Statistical Studies >>> _ Luiss SEP <https://sep.luiss.it/> School of European Political Economy >>> >>> >>> email: [email protected] >>> [email protected] >>> >>> _______________________________________________ >>> Qgis-user mailing list >>> [email protected] >>> List info: https://lists.osgeo.org/mailman/listinfo/qgis-user >>> Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user >>> >>> >> >> >> _______________________________________________ >> Qgis-user mailing list >> [email protected] >> List info: https://lists.osgeo.org/mailman/listinfo/qgis-user >> Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user >> > -- > [image: Logo] <https://spatialthoughts.com/> > Ujaval Gandhi > Spatial Thoughts > mobile: +91-8095684687 > email: [email protected] > [image: LinkedIn icon] <https://www.linkedin.com/in/spatialthoughts/> [image: > Twitter icon] <https://twitter.com/spatialthoughts> > >
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