Dear Reseachers,

I wish to save a "SpatialPixelsDataFrame" in several format (ascii, tiff,
jpg, ect ect) using writeGDAL, but I don't understand my error (it's the
first time I use this function)


str(grid.aggr)
Formal class 'SpatialPixelsDataFrame' [package "sp"] with 7 slots
  ..@ data       :'data.frame': 10816 obs. of  2 variables:
  .. ..$ ID: Factor w/ 10816 levels "1","2","3","4",..: 1 2 3 4 5 6 7 8 9 10
...
  .. ..$ H : num [1:10816] 0.298 0.385 0.378 0.539 0.372 ...
  ..@ coords.nrs : num(0)
  ..@ grid       :Formal class 'GridTopology' [package "sp"] with 3 slots
  .. .. ..@ cellcentre.offset: Named num [1:2] 264980 4146980
  .. .. .. ..- attr(*, "names")= chr [1:2] "X" "Y"
  .. .. ..@ cellsize         : Named num [1:2] 10 10
  .. .. .. ..- attr(*, "names")= chr [1:2] "X" "Y"
  .. .. ..@ cells.dim        : Named int [1:2] 104 104
  .. .. .. ..- attr(*, "names")= chr [1:2] "X" "Y"
  ..@ grid.index : int [1:10816] 1 2 3 4 5 6 7 8 9 10 ...
  ..@ coords     : num [1:10816, 1:2] 264980 264990 265000 265010 265020 ...
  .. ..- attr(*, "dimnames")=List of 2
  .. .. ..$ : NULL
  .. .. ..$ : chr [1:2] "X" "Y"
  ..@ bbox       : num [1:2, 1:2] 264975 4146975 266015 4148015
  .. ..- attr(*, "dimnames")=List of 2
  .. .. ..$ : chr [1:2] "X" "Y"
  .. .. ..$ : chr [1:2] "min" "max"
  ..@ proj4string:Formal class 'CRS' [package "sp"] with 1 slots
  .. .. ..@ projargs: chr NA


> class(grid.aggr)
[1] "SpatialPixelsDataFrame"
attr(,"package")
[1] "sp"
tf <- tempfile()
> writeGDAL(grid.aggr,tf, drivername="GTiff", type="Byte", options=NULL)
*Errore in create2GDAL(dataset = dataset, drivername = drivername, type =
type, : Numeric bands required*


thanks in advance and sorry for desturb
Gianni

	[[alternative HTML version deleted]]

