When trying the example below, I can't reproduce your problem. Could you provide us with the output of sessionInfo(), and a way to reproduce your problem?
library(sp) data(meuse.grid) gridded(meuse.grid) = ~x+y summary(meuse.grid) meuse.grid$B = meuse.grid$dist > .2 summary(meuse.grid) summary(as(meuse.grid, "SpatialGridDataFrame")) # try a single band grid: m = SpatialPixelsDataFrame(as(meuse.grid, "SpatialPixels"), data.frame(B = meuse.grid[["B"]])) summary(m) summary(as(m, "SpatialGridDataFrame")) On 10/20/2010 12:56 PM, ElenaC wrote: > > Dear all, > > I'm having trouble doing what I thought would be a very simple conversion. I > have a SpatialPixelsDataFrame variable which has a single data attribute, a > logical variable: > >> summary(data_pixels) > Object of class SpatialPixelsDataFrame > Coordinates: > min max > coords.x1 -180 180 > coords.x2 -60 60 > Is projected: NA > proj4string : [NA] > Number of points: 3972 > Grid attributes: > cellcentre.offset cellsize cells.dim > coords.x1 -179.5 1 360 > coords.x2 -59.5 1 120 > Data attributes: > Mode FALSE TRUE NA's > logical 3733 239 0 > > > When I try to convert it to SpatialGridDataFrame, for some reason I lose all > the grid cells which were TRUE: > >> data_grid <- as(data_pixels,'SpatialGridDataFrame') >> summary(data_grid) > Object of class SpatialGridDataFrame > Coordinates: > min max > coords.x1 -180 180 > coords.x2 -60 60 > Is projected: NA > proj4string : [NA] > Number of points: 2 > Grid attributes: > cellcentre.offset cellsize cells.dim > coords.x1 -179.5 1 360 > coords.x2 -59.5 1 120 > Data attributes: > Mode FALSE NA's > logical 3733 39467 > > > Sorry if this is really obvious, but I don't understand why this is > happening. What I wanted to do was keep both the FALSE and TRUE data and > fill in all the rest of the grid cells with NAs. Any hint would be greatly > appreciated! > > Regards, > Elena -- 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.pebe...@wwu.de _______________________________________________ R-sig-Geo mailing list R-sig-Geo@stat.math.ethz.ch https://stat.ethz.ch/mailman/listinfo/r-sig-geo
