I'm looking for tools and extensions in open source platforms (gvSIG, QGIS, uDig, etc) that allows 3D snapping.

In the last years, most of the projects my company is working on required the editing of 2.5D cartography. 3D snapping is a crucial feature for these projects. And the designers fell more comfortable using CAD tools (like Microstation Geographics) for digitalizing and editing on this projects. ArcGis 9.3 with a 3D snap plugin is used in the second half of the editing part (soon will use ArcGis 10).

Now my company wants to start working with open source platforms (hooray!), and the 3D snapping seems to be one of the main holes in the open source GIS platforms.

Do you know anything could be useful on this subject? Tools, extensions, initiatives, etc.

  • 1
    What's a 3D snap plugin for ArcGIS? Can you link that reference? Don't know of any snapping extensions for the open source platforms you listed. Have you tried SketchUp? Not sure it it will do for your purposes but it has the best 3D (not 2.5D like ArcScene) environment with all sorts of really usefull inference points lines and angles. – Jakub Sisak GeoGraphics Apr 30 '12 at 0:05
  • Link to 3d snap pluguin added. It's no very stable, but better than manually modify the Z values. I will try SketchUp! Surely can be useful. – cag May 1 '12 at 15:13
  • I meant to say best 3D snapping environment (Sketchup comment above) although it is also just about the best and most intuitive 3D modelling environment. Too bad it does not do GIS a little better. – Jakub Sisak GeoGraphics May 1 '12 at 15:27
  • @cag, be aware that it is not only the z-value that is affected by 3d-snapping instead of 2d-snapping. Also the x and y values might be totally different. – Nicklas Avén May 3 '12 at 12:50

First, I don't know if any open source desktop gis is capable of 3d-snapping, but the wonderful thing about open source is that you can always fix it yourself or get someone else to fix it. Use some of the money you save from ArcGIS licenses on developing 3D snapping :-)

Depending on your workflow it might be of interest to know that PostGIS since version 2.0 have some 3D distance functionality that might help. In this blogpost, snapping points to linestrings in 2D is described and now you can do the same thing in 3D by using ST_3DClosestpoint and ST_3DDWithin instead.


  • Both Nicklas and Jakub make excellent suggestions. I think you are at the convergence point between the current state of GIS development and the 3D modelling world. – MappaGnosis Apr 30 '12 at 9:55
  • Seems like there is no other answer. I had in mind to develop a 3D snapping tool, just want to ensure that I will not reinvent the weel. :) – cag May 1 '12 at 15:38

There's an algorithm documented on the geotools site that possibly describes how it can be done. Although it seems like 2d I'm sure it can be extended to 3d, considering the algorithm code is available

  • Good link! I'm a bit familiar with geotools and that code could be very useful. – cag May 1 '12 at 15:53

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