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I have a dataset form a national agency with a topologically correct road-network. However, I have a problem when applying network analysis within QGIS to the dataset.

I have tried both the native network analysis and the QNEAT3-plugin.

The problem is that both algorithms lack a function that only accepts connectivity between lines at start and end node of each line. Consequently, the network algorithm "turns" everytime there is a common vertex between two roads which is a problem at bridges and underpasses etc (see picture below).

enter image description here

As one can see the shortest-path algorithm turns to the north (where it shouldn't). This could all be avoided by allowing a parameter that only accepts connectivity at start and end node of a line.

My vague memory tells me it is possible in ESRI products. Is there any plugin that allows this for QGIS?

Vince
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ConcreteJungle
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    In my understanding, if two lines that (visually) cross have a common vertex at the crossing point, they are connected in the network. You have to remove the common vertex to get rid of this connection. – Babel Mar 22 '22 at 15:40
  • Hi, thats correct. However, the dataset is large so moving vertexes manually is not an option. That's why aim looking for an algorithm that alows for connectivity only at start and end node. – ConcreteJungle Mar 23 '22 at 07:03
  • Finding an automatized way to remove thise connecting vertices would be an alternative. Like: identify the vertices where lines should not "cross" and creating on both lines two new vertices, slightly shifted away from the cross point. Maybe worth asking another question for this in case there is no answer here? – Babel Mar 23 '22 at 08:00
  • Hi, yes if there is no suitable algorithm that can be applied to the dataset, that is a solution. I'l ask another question on this forum on that topic. – ConcreteJungle Mar 24 '22 at 06:41
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    Ive asked a new question here:https://gis.stackexchange.com/questions/426949/deleting-overlaping-vertex-between-line-features-if-not-start-end-vertex – ConcreteJungle Mar 24 '22 at 07:03

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