conn.open_gdal: Open GDAL file

In ursa: Non-Interactive Spatial Tools for Raster Processing and Visualization

Open GDAL file

Description

open_gdal creates object of ursaRaster class, and prepares connections for data reading.

Usage

open_gdal(fname, engine=c("native", "sf", "gdalraster", "vapour"), verbose = FALSE)

ursa_open(fname, verbose = FALSE)

Arguments

fname	Character. Filename; full-name or short-name.
engine	Character. Functionality of which package is used for reading data. This is experimental list, which future depends on evolution of reviewed packages and their availability for partial reading of multiband rasters.
verbose	Logical. verbose=TRUE provides some additional information on console. Default is FALSE.

Details

ursa_open is a synonym to open_gdal. Generally, both function names are abridged version of ⁠ursa_open_dgal⁠.

open_gdal doesn't read data. Data can be read later using Extract operator [.

If argument fname is ENVI .hdr Labelled Raster then either open_gdal or open_envi can be used. The former provides external implementation for data reading via GDAL in rgdal package.

Value

Returns object of class ursaRaster. Values are not in memory.

Author(s)

Nikita Platonov [e-mail]

See Also

close, open_envi, read_gdal.

Examples

session_grid(NULL)
# fname1 <- system.file("pictures/cea.tif",package="rgdal")
fname1 <- system.file("tif/geomatrix.tif",package="sf")
message(fname1)
a1 <- open_gdal(fname1)
print(a1)
print(a1[])
close(a1)
# fname2 <- system.file("pictures/test_envi_class.envi",package="rgdal")
fname2 <- tempfile(fileext=".")
a <- ursa_dummy(1,resetGrid=TRUE)
b <- colorize(a[a>91],stretch="equal",name=format(Sys.Date()+seq(0,6),"%A %d"))
write_envi(b,fname2)
message(fname2)
b1 <- open_gdal(fname2)
b2 <- open_envi(fname2)
print(b1)
print(b2)
print(c('The same grid?'=identical(ursa_grid(b1),ursa_grid(b2))
       ,'The same data?'=identical(ursa_value(b1[]),ursa_value(b2[]))))
close(b1,b2)
envi_remove(fname2)

ursa documentation built on April 3, 2025, 6 p.m.