gdalUtils (version 2.0.1.5)

gdaltransform: gdaltransform

Description

R wrapper for gdaltransform: transforms coordinates

Usage

gdaltransform(srcfile, dstfile, coords, s_srs, t_srs, to, order, tps, rpc,
  geoloc, i, gcp, output_xy, ignore.full_scan = TRUE, verbose = FALSE)

Arguments

srcfile
Character. File with source projection definition or GCP's. If not given, source projection is read from the command-line -s_srs or -gcp parameters.
dstfile
Character. File with destination projection definition.
coords
Matrix. A two-column matrix with coordinates.
s_srs
Character. source spatial reference set. The coordinate systems that can be passed are anything supported by the OGRSpatialReference.SetFromUserInput() call, which includes EPSG PCS and GCSes (ie. EPSG:4296), PROJ.4 declarations (as above), or the name of
t_srs
Character. target spatial reference set. The coordinate systems that can be passed are anything supported by the OGRSpatialReference.SetFromUserInput() call, which includes EPSG PCS and GCSes (ie. EPSG:4296), PROJ.4 declarations (as above), or the name of
to
Character. "NAME=VALUE". set a transformer option suitable to pass to GDALCreateGenImgProjTransformer2().
order
Numeric. order of polynomial used for warping (1 to 3). The default is to select a polynomial order based on the number of GCPs.
tps
Logical. Force use of thin plate spline transformer based on available GCPs.
rpc
Logical. Force use of RPCs.
geoloc
Logical. Force use of Geolocation Arrays.
i
Logical. Inverse transformation: from destination to source.
gcp
Character. pixel line easting northing [elevation]: Provide a GCP to be used for transformation (generally three or more are required)
output_xy
Logical. (GDAL >= 2.0) Restrict output to "x y" instead of "x y z"
ignore.full_scan
Logical. If FALSE, perform a brute-force scan if other installs are not found. Default is TRUE.
verbose
Logical. Enable verbose execution? Default is FALSE.

Value

  • Numeric.

Details

This is an R wrapper for the 'gdaltransform' function that is part of the Geospatial Data Abstraction Library (GDAL). It follows the parameter naming conventions of the original function, with some modifications to allow for more R-like parameters. For all parameters, the user can use a single character string following, precisely, the gdalinfo format (http://gdal.org/gdaltransform.html), or, in some cases, can use R vectors to achieve the same end.

This function assumes the user has a working GDAL on their system. If the "gdalUtils_gdalPath" option has been set (usually by gdal_setInstallation), the GDAL found in that path will be used. If nothing is found, gdal_setInstallation will be executed to attempt to find a working GDAL.

References

http://www.gdal.org/gdaltransform.html

Examples

Run this code
# We'll pre-check to make sure there is a valid GDAL install.
# Note this isn't strictly neccessary, as executing the function will
# force a search for a valid GDAL install.
gdal_setInstallation()
valid_install <- !is.null(getOption("gdalUtils_gdalPath"))
if(valid_install)
{
pts <- matrix(c(177502,311865,177503,311866),ncol=2,byrow=TRUE)
gdaltransform(s_srs="EPSG:28992",t_srs="EPSG:31370",coords=pts,verbose=TRUE)
}

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