I've made a distance matrix from one point layer (layer A) to another (layer B) using QNEAT plugin (QGIS Network Analysis Toolbox 3).
I got a web with links from every point from A to every point from B, but I don't need that many links. I need to have unique links from A to B, and once a point from B is taken by any point from A, it cannot be selected for a link.
In other words, I'm looking for a way to filter the data which I got using QNEAT.
What you want to do can only work if you have the same number of points in both layers, so I suppose this is the case.
So basically, for each feature of layer A (in QNEAT output referenced with origin_id) you want to get a distinct/unique feature of layer B (destination_id) linked - as shown in the screenshot, the selected features (marked in blue):
This can be done selecting the smallest origin_id with the smallest destination_id, second smallest origin_id with second smallest destination_id etc. To do so, use Select by Expression with this expression:
destination_id =
array_get (
array_sort (
array_distinct(
array_agg (destination_id)
)
),
array_find (
array_sort (
array_distinct(
array_agg (origin_id)
)
),
origin_id
)
)
In general, the 'Join by lines (hub lines)' tool will connect points in A to the nearest point in B. However, as far as I know, there is no tool that ensures that every point in B is assigned to at most one point in A.
