[R] How to use your own data in gstat and sp?
Roger.Bivand at nhh.no
Mon Aug 17 12:34:24 CEST 2009
First re-read the definition of what a SpatialPixels object is -
?"SpatialPixels-class" - note that it says: "class for defining a pixels,
forming a possibly incomplete rectangular grid of arbitrary dimension". When
you try to coerce a SpatialPointsDataFrame to a SpatialPixelsDataFrame, it
is checked to see that the points form a "possibly incomplete rectangular
grid". Your points are random within a 1,10 square, so only regularly spaced
for a very special setting of the seed of the RNG, right? Since you are
unlikely to hit that very, very rare seed at random, you are not likely to
generate a regular grid in this way. Did you examine the class(), summary()
and str() of the input data in the examples?
Hope this helps,
PS. consider following this up on the R-sig-geo list.
Paul Heinrich Dietrich wrote:
> This seems pretty basic, but I can't get any data to work except for the
> documented examples. When the goal is to get to SpatialPixels, here is
> what I see...
>> x <- runif(10,1,10)
>> y <- runif(10,1,10)
>> z <- rnorm(10,0,1)
>> MyData <- as.data.frame(cbind(x,y,z))
>> coordinates(MyData) <- ~x + y
>> gridded(MyData) <- TRUE
> suggested tolerance minimum: 0.893182669294186
> Error in points2grid(points, tolerance, round, fuzz.tol) :
> dimension 1 : coordinate intervals are not constant
> I've spent way too much time trying to get my data to work. Please help.
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