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SpaceGroupUCL / qgisSpaceSyntaxToolkit

Space Syntax Toolkit for QGIS
GNU General Public License v3.0
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Unlinks not unlinking #193

Open deepthijhn opened 2 years ago

deepthijhn commented 2 years ago

Unlinks are verified and the IDs for Line 1 and Line 2 are matching with the line IDs they need to unlink. However, the analysis does not unlink them. The Toolkit version is 0.2.1 for QGIS 2.18 and as well as 0.3.9 for QGIS 3.20. Tested on multiple layers as well. Running on Windows. image

jorgegil commented 2 years ago

@deepthijhn the concept of unlinks is only relevant when you depart from an axial map. They exist to indicate where axial lines that intersect do not allow a change of direction.

When departing from segments or road centre lines, the line segments are already broken at crossings. And if there is no crossing and a change of direction is not possible, then the line segments should not be broken where they intersect, and simply cross over each other. This is the "standard" convention in road centre line representation. So the unlinks are not considered.

In your case, it looks like you have an issue with the road centre line representation. There's a bridge or tunnel that is broken in pieces, and you want to unlink from the other lanes. To do this you should either dissolve the segments to create a single line, or move the endpoints of the various segments so that they do not touch. Whichever you find easier.

Jorge

deepthijhn commented 2 years ago

Jorge, thank you so much for the reply. The map was an axial map with unlinks. The screenshot I included is the analyzed result, where it is shown that the axial lines did not unlink when the analysis was run. The same axial map was run in Depthmap .35 directly and it worked just fine. However, my preference would be to make it work in QGIS for obvious reasons of easier workability.

jorgegil commented 2 years ago

Thanks for the clarification.

It should have worked, I've just testes and there's no obvious bug. Please ensure that all layers and also the project are in the same coordinate system (CRS). Also, make sure you update the unlink IDs, and that they are verified. If you edit unlinks, save the layer before the analysis.