[R-sig-Geo] Warning: longlat data cannot do quadtree [variogram]

[Edzer Pebesma]

You can ignore it.

gstat builds quadtrees (or oct-trees in 3d) to efficiently find out
which observations are near others. For data on the sphere, using great
circle distance, this does not work, at least as far as I can see.

I would agree that the warning message is, well, somewhat cryptic.

On 01/21/2011 06:29 PM, piero campa wrote:
> 
> Hi all,
> I was trying to understand the reason of the above-mentioned warning, which
> is thrown as I try to compute (cross-)variograms on a gstat object but I
> found no information in this forum nor elsewhere.
> 
> The gstat object is built over a SpatialPixelsDataFrame and a
> SpatialPointsDataFrame.
> The coordinate information is in longlat and the projection is the
> following:
> projargs: chr " +proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs
> +towgs84=0,0,0"
> 
> Do you have any clue about this?
> Thank you,
> Piero
> 

-- 
Edzer Pebesma
Institute for Geoinformatics (ifgi), University of Münster
Weseler Straße 253, 48151 Münster, Germany. Phone: +49 251
8333081, Fax: +49 251 8339763  http://ifgi.uni-muenster.de
http://www.52north.org/geostatistics      e.pebesma at wwu.de