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I have a polyline layer and a points layer with features that are nearby the polylines. For the latter I want to find the closest points on the polylines (as existing vertices or new-created vertices along the polylines).

My initial approach is to loop through all polylines and check if their bounding boxes with a bit of buffer are intersecting the given points, so 2 for-loops then for each polyline candidate to loop through vertices and apply the distance point-line algorithm to find the closest point. But can become very slow especially for large datasets.

I've quickly checked Quadtrees but I see they are optimized for storing and fast lookup of point features. Is there anything similar for polylines or rectangles (bounding boxes)?

Later edit: I'm more interested in the algorithm / ways to store data because it's part of the software that I am implementing at this moment. So any existing GIS software / plugins examples are ok but I want to see what's "under the hood".

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    You have neglected to mention which GIS software you want to do this in? – Hornbydd Dec 27 '19 at 0:36
  • I've edited my post, is actually part of the software that I am writing so I want to understand the mechanics behind the existing GIS tools out there. – Fred Dec 27 '19 at 8:28
  • On such tool is Turf.js, see github.com/Turfjs/turf. – TomazicM Dec 27 '19 at 12:25
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Welcome to the site. The question is a bit vague, but if you are using ArcGIS, you will most likely want to use proximity analysis (https://desktop.arcgis.com/en/arcmap/10.3/analyze/commonly-used-tools/proximity-analysis.htm).

This chart shows the different combinations of geometry for these operations with the one you described circled in yellow. (https://pro.arcgis.com/en/pro-app/tool-reference/analysis/how-near-analysis-works.htm)

distances

In QGIS, there is a plugin called "NNjoin" that does something similar (https://plugins.qgis.org/plugins/NNJoin/)

Once you have the distances for all of your points, you can filter them accordingly.

  • Thanks for the answer, I'm actually need the solution to implement it in a software that I am writing. The ESRI tool is nice but I guess I cant see the source code, I'll have a look at the NNJoin plugin instead, thanks! – Fred Dec 27 '19 at 8:31

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