[R-sig-Geo] a comparison question

[Wissner, Michael (DOF)]

Erin,

My (basic) understanding of these two techniques is that kriging outputs a predictive surface with values derived from a variogram while GWR executes a regression equation on each feature in a dataset with a spatial weighting component.  So I think the answer to your question is that it depends on what output you're looking for and what you're trying to accomplish.

>From ESRI's How Kriging Works (http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#//009z00000076000000.htm)... "it has been said that kriging uses the data twice: the first time to estimate the spatial autocorrelation of the data and the second to make the predictions."

>From ESRI's How GWR Works (http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#//005p00000031000000)... "GWR provides a local model of the variable or process you are trying to understand/predict by fitting a regression equation to every feature in the dataset. GWR constructs these separate equations by incorporating the dependent and explanatory variables of features falling within the bandwidth of each target feature."

Thus, kriging fits a model based on the paired distances then applies that to predict an entire surface of a single z-value (variable). I think consensus among geostatisticians says that kriging is the best for spatial prediction of a single variable.
GWR permits a whole set of explanatory variables to be analyzed and included in a spatially weighted regression model unique to each feature.  I think this technique more suited for exploring how a complete set of independent variables varies in its explanatory power across the spaces analyzed.

I hope this is useful.  I am by no means an authority on this and will keep a close eye on this thread.  

Chao, mike




-----Original Message-----
From: r-sig-geo-bounces at r-project.org [mailto:r-sig-geo-bounces at r-project.org] On Behalf Of Hodgess, Erin
Sent: Wednesday, March 05, 2014 3:03 PM
To: r-sig-geo at r-project.org
Subject: [R-sig-Geo] a comparison question

 Hello everyone:

Here is a comparison question, please:  is kriging better than GWR, please?  Or are they even comparable, please?

Thanks,
Erin


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