[Qgis-user] OTB8.0.1-Learning-TrainImagesClassifier

[Alex Bley via Qgis-user]

Good afternoon!
When i use the OTB8.0.1-Learning-TrainImagesClassifier in area "Input
Vector Data List" i have the message: "could not load selected table/layer.
Dependent field cannot be filled".
So, how can i fix this problem?
I think the problem is in version 8.0.1
I use Qgis 3.16.
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Re: [Qgis-user] help with shortest-path/network analysis (multiple origins to multiple destinations)

[Francesca Parente via Qgis-user]

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 <
uja...@spatialthoughts.com> 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 <
> qgis-user@lists.osgeo.org> 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 runcodeexec(code,
>> self.locals)  File "", line 1, in   File
>> "C:/OSGEO4~1/apps/qgis/./python\qgis\utils.py", line 799, in _importmod
>> = _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 <
>> njacadieux.git...@gmail.com> 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://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 <
>>> qgis-user@lists.osgeo.org> 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
>>>  in
>>> SocioEconomic and Statistical Studies
>>> _ Luiss SEP  School of European Political Economy
>>>
>>>
>>> email: 

Re: [Qgis-user] Trapping Kyb/Mouse events during a QGIS geometry edit process

[Richard Duivenvoorde via Qgis-user]

I'd start to look into the advanced digitizing tools code, or in some (older?) 
cad-like plugins (QAD is a pretty extensive one)? They often also show 
position/angle/whatever info?

The 'thing' you see during digitizing, is (I think) a QgsGeometryRubberBand

https://qgis.org/pyqgis/3.22/gui/QgsGeometryRubberBand.html#module-QgsGeometryRubberBand

That one has a lot of events

HTH,

Richard

On 5/7/22 10:46, Zoltan via Qgis-user wrote:

Hi Listers,
I'm looking for some pointers as where to start, or keywords to google or 
recipes to follow (if any).

I'm looking to trap kyb/mouse events whilst in the middle of a geometry edit.
If a suitable event is trapped, then to run a subroutine and then return to the 
edit process by either handing the edit process the same event or generating 
another event for the edit routine to continue the geometry edit with.

So I suppose my question is, is where do I insert such kyb/mse event filter.

Any pointers would be welcome.

Thanks in advance,
Zoltan



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[Qgis-user] Trapping Kyb/Mouse events during a QGIS geometry edit process

[Zoltan via Qgis-user]

Hi Listers,
I'm looking for some pointers as where to start, or keywords to google 
or recipes to follow (if any).


I'm looking to trap kyb/mouse events whilst in the middle of a geometry 
edit.
If a suitable event is trapped, then to run a subroutine and then return 
to the edit process by either handing the edit process the same event or 
generating another event for the edit routine to continue the geometry 
edit with.


So I suppose my question is, is where do I insert such kyb/mse event 
filter.


Any pointers would be welcome.

Thanks in advance,
Zoltan

--

=
Zoltan Szecsei GPrGISc 0031
Director, Geograph (Pty) Ltd.
GIS and Photogrammetric Services

Cape Town, South Africa.

Mobile: +27-83-6004028 (Signal, not WhatsApp)
www.geograph.co.za
=

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