AequilibraE project

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Elisa

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Jul 20, 2021, 11:46:17 AM7/20/21
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Hi everybody, 

I am totally new to AequilibraE and QGIS so apologies if my question may sound stupid. 

My goal is to create a PT network, add region centroid and then create centroid connections to the network. I went as far as creating the network following the tutorial, however whenever I try to create a project out of it, AequilibraE just tells me 'initialising project' (stays stuck at 0% for a while) and then actually creates a project with nodes and links that are empty. I follow step by step the tutorial and get no mistakes however the outcome is faulty. 

Whenever I try to add centroid connectors QGIS just quits unexpectedly. 

I am on mac, QGIS version 3.16 and python version 3.9

Thanks for all the help!

Elisa 


Pedro Camargo

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Jul 20, 2021, 5:55:38 PM7/20/21
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Hi Elisa, 

A few points:

* AequilibraE does not have transit assignment. 
* AequilibraE does not currently support Python 3.9 (so path computation won't work) 

On your current issue, it would be good to know what is the data you are using. Any chance it is ShapeFiles? 

Cheers, 
Pedro 


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Elisa

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Jul 26, 2021, 8:07:27 AM7/26/21
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Hi Pedro, 

Thanks a lot for your reply. I am trying to use AequilibraE to edit the Network, and then I'll do path computation with a program in C++ (I don't need transit assignment, I would only need to compute a distance matrix between all centroids, is that possible in AequilibraE?)

Anyway, I am using geojson to import the network of nodes and links, I create the network following the tutorial and then I have a shapefile with polygons, whose centroid I need to connect to the rest of the network. Are the shapefiles creating the problem? 

Thanks a lot for your help, 

Elisa 

Pedro Camargo

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Jul 26, 2021, 9:45:31 PM7/26/21
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Hi Elisa,
               AequilibraE does compute paths, and very quickly, I should add --> http://aequilibrae.com/python/latest/_auto_examples/plot_path_and_skimming.html#sphx-glr-auto-examples-plot-path-and-skimming-py

Shapefiles can create trouble inside QGIS because they automatically recognized as MultiLineString, instead of LineString. There is also the possibility that it is the same case for GeoJSON, so converting it to GeoPackage or Spatialite (and enforcing the geometry type to be LineString) could be a good alternative.

If you are comfortable with Python (and a little bit with its geo-manipulation packages), you can also create the entire project in Python, starting with creating the project itself and then creating new links (nodes are created automatically) http://aequilibrae.com/python/latest/_auto_examples/plot_moving_link_extremity.html


It might be worth it to go through the documentation in more detail, though.

Cheers,
Pedro


---- On Mon, 26 Jul 2021 22:07:27 +1000 Elisa <elisamaria...@gmail.com> wrote ----

Elisa

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Jul 27, 2021, 12:43:10 PM7/27/21
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Hi Pedro, 

Thanks again for your reply. I have tried converting my data to GeoPackage (and the geometry type is LineString) but still it says 'initialising', stays stuck at 0% and the eventually it creates an empty sqlite file. The Python version QGIS is using is 3.8 so in principle that should be fine, I do not understand where is the problem. 

As per my understanding it was not possible to create an Aequilibrae project directly from Python (using existing links and nodes) but maybe I have misunderstood something. Is there any documentation I could follow to create a project from python?

Thanks again, 

Elisa 

Jamie Cook

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Jul 28, 2021, 5:44:17 AM7/28/21
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Hi Elisa, I believe Pedro provided links to the relevant documentation in his previous email. Have you checked that out?

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- Jamie 

Elisa

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Jul 28, 2021, 5:56:38 AM7/28/21
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Hi Jamie, 
Yes I did check them out but there is no documentation on how to import an existing network, create a new project etc (only create it from OSM). Also there is a README file explicitly saying you cannot create a an AEQ project from Python yet, so I am confused on whether this is possible or not. 
Thanks again, 
Elisa  

Jamie Cook

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Jul 28, 2021, 6:08:20 AM7/28/21
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Yeah it's not exactly what you would need but could serve as a good starting point for you

The network data structures are documented here: http://aequilibrae.com/python/latest/project_docs/network.html

I believe that you could create an empty project and then manually import your link/node data into the database. The above link gives you the structure of the tables you would need to populate.


To view this discussion on the web visit https://groups.google.com/d/msgid/aequilibrae/3d4b9ca8-b574-453d-b0fa-b3de9f16567fn%40googlegroups.com.

Pedro Camargo

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Jul 28, 2021, 8:49:37 AM7/28/21
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You can absolutely create a project from scratch in Python, Elisa!

The idea is to create a new one and then add links and then add links one by one.

You will need to create the corresponding link types and modes first, but it should work well.  I can work with you to create a new example for the documentation covering that exact use case, if you feel like helping with that!

Cheers,
Pedro


---- On Wed, 28 Jul 2021 19:56:38 +1000 Elisa <elisamaria...@gmail.com> wrote ----

Elisa

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Jul 28, 2021, 9:49:47 AM7/28/21
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Hi Pedro, 
I would absolutely love to help you out drafting a documentation for that. AequilibriaE is a great project but I am struggling to find documentation so more than happy to contribute!
Best, 
Elisa  

Pedro Camargo

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Jul 29, 2021, 3:27:01 AM7/29/21
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Elisa,
            I took a crack at it, and I think you have the structure you would need to create a full-blown example.

It comes to mind that having a method such as create_from_GeoDataFrame would be awesome, and that would be a great opportunity for anybody here to contribute if they are interested.

Cheers,
Pedro

PS - Would you let me know whenever you have an idea of when you would finish this example?  I want to release the next version soon, and it would be great to have this in the documentation.


---- On Wed, 28 Jul 2021 23:49:47 +1000 Elisa <elisamaria...@gmail.com> wrote ----

project_from_links.ipynb
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