[Qgis-developer] Kriging interpolation functionality in QGIS?

[Stefan Keller]

Hi Barry

Many thanks for your explanations and hints.
So from a pragmatic point-of-view ("80/20 pareto rule"):
Do you think Inverse Distance Weighting (IDW) would do the job as well,
since Kriging has so many parameters to fiddle around and to understand?

:Stefan


2015-09-25 18:36 GMT+02:00 Barry Rowlingson <b.rowlingson at lancaster.ac.uk>:
> On Fri, Sep 25, 2015 at 4:14 PM, Stefan Keller <sfkeller at gmail.com> wrote:
>> Hi,
>>
>> I'm looking for a Kriging interpolation from an irregular point data
>> set to raster data in QGIS without dependencies, if possible. There's
>> 1.       Interpolation plugin (C++) [1]
>> 2.       „Raster Interpolation“ plugin von Denis Rouzaud (Python) [2]
>>
>> I know that GRASS and SAGA implemented Kriging [3].
>> But these are are dependencies I'd like to avoid in order to make QGIS
>> even more easier to use.
>> AFAIK even Denis' "Raster Interpolation" plugin requires Scipy
>> separately installed.
>>
>> So eventually, I'm considering to extend "Raster Interpolation" Python
>> plugin (or [1])
>> Any suggestions or activities regarding this?
>
>  You want Kriging in QGIS? You now have to implement a full
> statistical analysis system in QGIS. Kriging is hard, or even
> impossible to do properly as an automatic points-to-raster process
> without statistical diagnostics. You'll need to plot your variogram.
> You'll need to fit your variogram. You may need to transform your
> variables, and transform results back (and the back-transform of
> Kriging standard-errors is not trivial).
>
>  The simplest points-to-raster Kriging system I've seen is autoKrige
> from the R automap package. Even so this has about 7 parameters and
> options to choose from. Plus working in R makes it easy to plot
> diagnostics and histograms and do transforms and testing....
>
>  If you want to try all that, there's a few python kriging
> implementations that you could use, or this blog poster shows how to
> do it from scratch with basic matrix ops:
>
> http://connor-johnson.com/2014/03/20/simple-kriging-in-python/
>
> Barry