Sorry, I meant "UK variance of the interpolated logits". I guess the solution is to either:
(A) 1. Run 100 SG simulations using logits; 2. Back-transform the values to 0-1 scale; 3. Determine the variance per grid node (now in 0-1 scale). Running simulations could also be rather time-consuming (I often give up running SG simulations in gstat with multiple raster maps as predictors -- memory limit problems, too time-consuming). (B) 1. Determine the upper and lower 1-s confidence intervals -- 2 maps (in logit scale); 2. Back-transform the maps and derive the difference in 0-1 scale (estimation error); But I guess that a method to directly back-transform the UK variance from logit scale to 0-1 scale does not exist. Tom Hengl -----Original Message----- From: Edzer Pebesma [mailto:[EMAIL PROTECTED] Sent: woensdag 9 april 2008 14:48 To: Tomislav Hengl Cc: r-sig-geo@stat.math.ethz.ch Subject: Re: [R-sig-Geo] question about regression kriging Tomislav Hengl wrote: > PS: How do you back-transform the GLM prediction variance to original scale > (I was not aware of > this, apologies)? A reference would do. > 1. The white book, "Statistical Models in S" 2. The source of predict.glm (not for the faint of heart) 3. McCullogh & Nelder (I guess it's in there, but my copy is still in a box!) -- Edzer _______________________________________________ R-sig-Geo mailing list R-sig-Geo@stat.math.ethz.ch https://stat.ethz.ch/mailman/listinfo/r-sig-geo
