Class "GDALReadOnlyDataset"

Description

GDALReadOnlyDataset is the base class for a GDAL Dataset classes. Only read operations are supported. Both GDALDataset and GDALTransientDataset inherit these read operations while providing additional write operations (see GDALDataset-class). GDALReadOnlyDataset-class inherits from GDALMajorObject-class.

Usage

GDAL.close(dataset)
GDAL.open(filename, read.only = TRUE)
getDriver(dataset)
getColorTable(dataset, band = 1)
getGeoTransFunc(dataset)

Arguments

Details

GDAL.open and GDAL.close are shorter versions of new("GDALReadOnlyDataset", ...) and closeDataset(). Because GDAL.close through closeDataset() uses the finalization mechanism to destroy the handles to the dataset and its driver, messages such as:

"Closing GDAL dataset handle 0x8ff7900... destroyed ... done."

may appear when GDAL.close is run, or at some later stage. getDriver returns an object inheriting from class 'GDALDriver'. getColorTable returns the dataset colour table (currently does not support RGB imaging). getGeoTransFunc returns a warping function.

Objects from the Class

Objects can be created by calls of the form new("GDALReadOnlyDataset", filename, handle). ~~ describe objects here ~~

Slots

handle:

Object of class "externalptr", from class "GDALMajorObject" ~~

Extends

Class "GDALMajorObject", directly.

Methods

closeDataset

signature(dataset = "GDALReadOnlyDataset"): ...

dim

signature(x = "GDALReadOnlyDataset"): ...

initialize

signature(.Object = "GDALReadOnlyDataset"): ...

Author(s)

Timothy H. Keitt, modified by Roger Bivand

References

http://keittlab.bio.sunysb.edu/R/GDAL/, http://www.gdal.org/

See Also

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

Examples

logo <- system.file("pictures/logo.jpg", package="rgdal")[1]
x <- new("GDALReadOnlyDataset", logo)
dim(x)
plot(density(getRasterTable(x)$band1))
#displayDataset(x)
#displayDataset(x, col=function(x){rev(cm.colors(x))})
#im <- displayDataset(x, col=function(x){rev(cm.colors(x))}, reset.par=FALSE)
#contour(1:attr(im, "size")[2], 1:attr(im, "size")[1],
# t(attr(im, "index"))[,attr(im, "size")[1]:1], nlevels = 1,
# levels = 100, col = 'black', add = TRUE)
GDAL.close(x)
logo <- system.file("pictures/Rlogo.jpg", package="rgdal")[1]
x <- new("GDALReadOnlyDataset", logo)
dim(x)
#displayDataset(x)
GDAL.close(x)