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Disconnected Islands Modified QGIS 4 compatibility
QGIS 4 ready Active
Yes — Disconnected Islands Modified supports QGIS 4 (declared max version 4.99.0).
Finds disconnected "islands" in a transport network layer, so that a routing tool will work between all nodes, duplicates the selected line layer to modify geometry and make the lines closest to the select point layer converge onto with context. A tolerance field allows for imperfect topology. Now supports options for vertices. Original author "Peter Smythe @ AfriGIS"
About
This plugin runs on a polyline layer, building up a road (or rail, etc.) network graph of connected links and make an lines close to the selected points converge on that point with context. It then analyses connected subgraphs, ones that are connected to each other, but not connected to isolated or floating links. It creates an additional attribute containing the group ID of the subgraph. This can then be used to style the layer with Categorised styles, or Zoom to selection. The disconnected links can then be fixed. <br/> Version 2.1.0 introduces a new option to only use the start and end vertices of a road link (previously all vertices were considered.) A group ID of -1 (hidden) indicates a second road link with exactly the same start and end vertices as another road link, but probably with different in-between vertices. <br/> Based on Detlev's answer to my question: http://gis.stackexchange.com/questions/184319/how-to-find-disconnected-islands-in-a-road-network-layer-using-qgis <br/> DISCLAIMER: It does modify geometry, but instead of modifying the original geometry it creates a new layer on which it simply copies the original geometry and recreates it, and modifies that<br/> Sample data to test this plugin can be found: - in your plugins directory: ...QGIS/QGIS3/profiles/default/python/plugins/disconnected-islands-modified/sample-data/islands.zip - via GitHub: https://github.com/gR1ox/QGISDisconnectedIslandsModified/tree/main/sample-data/islands.zip<br/> This plugin depends on the NetworkX module. Mac OS X users need to install it manually, simply by executing, in a Terminal: sudo easy_install networkx. Then restart QGIS.
| Author | Magnus Jespersgaard |
|---|---|
| Downloads | 12 |
| Latest version | 2.3.1 |
| Last updated | 2026-11-13 (0 days ago) |
| Min QGIS | 3.0.0 |
| Max QGIS | 4.99.0 |
| QGIS 4 ready | Yes |
| Maintenance | Active |
| Categories | Network & routing, Vector tools |
| Tags | analysis, network analysis, network, polyline, processing, routing, topography |
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Maintenance: Active = updated within 1 year, Quiet = 1–3 years, Likely abandoned = over 3 years.