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I did recently a map of maximum temperature for specific area in Quantum GIS 1.8.0 and its interpolation. However, I was wondering if there are only two method of interpolation, apart from ‘Triangulated Irregular Network (TIN)’ or ‘Inverse Distance Weighted (IDW)’. Maybe is there any extra plugin for that?

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  • I feel this is a QGIS weakness. Of the two one is TIN and the IDW is a bit of a black box and does not allow the user to set many of the input parameters. Good question and I hope we get some answers.
    – user17614
    Commented Aug 4, 2013 at 17:19

2 Answers 2

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If you will install SAGA GIS, you will have Kriging and Spline interpolation available via SEXTANTE plugin.

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    If you are going to install SAGA make sure that you get version 2.0.8. This is the one that Sextante expects. N.
    – nhopton
    Commented Aug 4, 2013 at 14:19
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Okay I dug into this a little. I installed the OSGeo4W build of QGIS installed (1.8) with the Grass version it comes with.

In the Sextante tool box are all the various splines.

v.surf.xxx they are listed under.

Nearest neighbor analysis is r.resample

I see kriging is available (all the major ones) in Qgis via sda4pp How to install SDA4PP plugin for Kriging in QGIS?

So it seems most are available.

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  • Thank you for help. I installed Sextante tool box but I have some issues, eg. I chose v.surf.idw or r.resamp.interp and I had message: "Could not load layer: C:\...tif", in logs: "Could not load model watersheds.model ALGORITHM:saga:catchmentarea(parallel)". Could you tell me why did I get the error?
    – Mark
    Commented Aug 5, 2013 at 21:30
  • no problem. Try this. If you go to the SEXTANTE configuration dialog, you will see a "GRASS" entry, and there is an option to enable console output logging. Enable it, run your GRASS command again...and then send the log information. this is the stack explanation. gis.stackexchange.com/questions/57233/…
    – user17614
    Commented Aug 5, 2013 at 22:43
  • I enabled console output logging and I have the error log as follows: "Could not load model watersheds.model ALGORITHM:saga:catchmentarea(parallel)" "sextante.runalg("grass:v.surf.idw","C:/Users/Jarek/Desktop/granice/stacje1992.shp",12,2,"temperatur",False,"188032.55881,820240.953755,107812.241009,766913.732409",0,-1,0.0001,None)"
    – Mark
    Commented Aug 6, 2013 at 12:01

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