rgdal (version 1.2-5)

GDALReadOnlyDataset-methods: subset methods for "GDALReadOnlyDataset"

Description

subsets GDAL objects, returning a SpatialGridDataFrame object

Methods

Details

The [ method subsets a GDAL data set, returning a SpatialGridDataFrame object. Reading is done on the GDAL side, and only the subset requested is ever read into memory.

Further named arguments to [ are to either getRasterTable or getRasterData:

the other arguments, offset and region.dim are derived from row/column selection values.

An GDALReadOnlyDataset object can be coerced directly to a SpatialGridDataFrame

See Also

See also readGDAL GDALDriver-class, GDALDataset-class, GDALTransientDataset-class, SpatialGridDataFrame-class .

Examples

library(grid)
logo <- system.file("pictures/logo.jpg", package="rgdal")[1]
x <- new("GDALReadOnlyDataset", logo)
dim(x)
x.sp = x[20:50, 20:50]
class(x.sp)
summary(x.sp)
spplot(x.sp)
GDAL.close(x)

logo <- system.file("pictures/Rlogo.jpg", package="rgdal")[1]
x.gdal <- new("GDALReadOnlyDataset", logo)
x = x.gdal[,,3]
dim(x)
summary(x)
spplot(x)
spplot(x.gdal[])
GDAL.close(x.gdal)

logo <- system.file("pictures/Rlogo.jpg", package="rgdal")[1]
x.gdal <- new("GDALReadOnlyDataset", logo)
x.as <- as(x.gdal, "SpatialGridDataFrame")
GDAL.close(x.gdal)
summary(x.as)