Re: [R] variograms and kriging

From: <Steve_Friedman_at_nps.gov>
Date: Fri, 25 Jun 2010 13:54:56 -0400


Please disregard. I've posted to the wrong site.

Steve Friedman Ph. D.
Spatial Statistical Analyst
Everglades and Dry Tortugas National Park 950 N Krome Ave (3rd Floor)
Homestead, Florida 33034

Steve_Friedman_at_nps.gov
Office (305) 224 - 4282
Fax (305) 224 - 4147

                                                                           
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             06/25/2010 01:38          [R] variograms and kriging          
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Hello

Trying to develop variograms and kriged surfaces from a point file. Here is what I've done so far.

library(gstat) # also loads library(sp) library(lattice)

 soilpts$x <- soilpts$UTM_X
 soilpts$y <- soilpts$UTM_Y
 soil.dat <- subset(soilpts, select=c(x, y, Area, BulkDensity, LOI, TP, TN, TC, Total_Mg))

dim(soil.dat)
[1] 1292 7

 coordinates(soil.dat) <- ~ x+y

 gridded(soil.dat) <- TRUE

Warning messages:
1: In points2grid(points, tolerance, round, fuzz.tol) :   grid has empty column/rows in dimension 1 2: In points2grid(points, tolerance, round, fuzz.tol) :   grid has empty column/rows in dimension 2

 class(soil.dat)
[1] "SpatialPixelsDataFrame"
attr(,"package")
[1] "sp"
> bbox(soil.dat)

      min max
x 476819 575981
y 2785749 2948128

> soil.dat[1:3,]

suggested tolerance minimum: 0.165318957771788 Error in points2grid(points, tolerance, round, fuzz.tol) :   dimension 1 : coordinate intervals are not constant

The last error message and the warning returned above, leads me to think that the spatial sampling locations must be regular equally spaced. My data thou is not

I have spent the morning trying to figure this out - going back and forth among many spatial packages that can do variograms and krigging. Without a good road map to follow however, I've had to a number of about faces. Not sure which way to turn now.

Can anyone provide guidance?

Using Windows WP and R 2.11.1 packages updated today.

Thanks
Steve

Steve Friedman Ph. D.
Spatial Statistical Analyst
Everglades and Dry Tortugas National Park 950 N Krome Ave (3rd Floor)
Homestead, Florida 33034

Steve_Friedman_at_nps.gov
Office (305) 224 - 4282
Fax (305) 224 - 4147



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R-help_at_r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. Received on Fri 25 Jun 2010 - 17:58:13 GMT

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