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The Question

Are there any open source tools for conflating (matching) two layers of point (node) data?


I'm particularly interested in using such a tool to sync data with OpenStreetMap, where I've created a wiki page on the subject of conflation. That page links to some university research projects on the conflation of vector datasets using open source software (OpenJUMP and Quantum GIS), however they don't share their work.

Implementation if tool doesn't exist

I know algorithmically this task shouldn't be that difficult especially compared to handling generic vectors, as it would simply use distance and similar properties along with some math, however I suppose I'm more interested in a graphical interface implemented in open source software.

I wrote up a possible workflow for conflating nodes here on the OSM wiki. I thought of trying to implement it in JOSM, however if there are others from the broader GIS community interested in this then it would make sense to implement it in something like QGIS, especially if other developers would get involved.

Use cases

I think it might be useful to say what I'd be interested in using this tool for.

  • Syncing Virginia interstate exit data from VDOT with OSM
  • Syncing GNIS feature points with OSM

After an extension to conflate polygons (using their centroids), the tool could also be used for:

  • Transferring properties (tags, attributes) between nodes representing a house along with addressing data to a polygon (area, closed way) of the actual building

I'm sure there are many other possibilities, but these are the few I'm planning to use it for.

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I'd be interested to know if you've researched the automated conflation software called MapMerger (offered by ESEA, in California). Their conflation tool automates much of the matching process, and includes a robust set of manual matching and editing tools. And it has a great UI. It's an ArcMap extension. – user37099 Sep 16 '14 at 21:21

Probabbly you have seen this but ther it is in case you didn't, it works with Jump.


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I've heard of the Java Topology Suite (JTS), but not the Java Conflation Suite (JCS), though it appears JCS uses JTS. JCS hasn't been updated since 2003, so it likely will require some work to get it running with the most recent OpenJUMP edition. I've created a repository at Github using the 1.0.0 and 1.0.1 releases from Vivid Solutions. Is anyone using JCS these days? – joshdoe Apr 7 '11 at 16:09
I should add that I've also come across RoadMatcher, an OpenJUMP plugin based on JCS for conflating roads. I'd like to get to that eventually, but for now the node conflation would be more readily useful. I haven't gotten JCS working yet, but it doesn't appear to offer the kind of node conflation I'm looking for. Perhaps this process is not called conflation? The JCS docs all talk about conflating polygons and edges (ways). – joshdoe Apr 7 '11 at 16:52

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