gdaltransform: gdaltransform

In gdalUtils: Wrappers for the Geospatial Data Abstraction Library (GDAL) Utilities

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 a .prf file containing well known text.
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 a .prf file containing well known text.
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.

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.

Value

Numeric.

Author(s)

Jonathan A. Greenberg ([e-mail]) (wrapper) and Frank Warmerdam (GDAL lead developer).

References

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

Examples

# 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)
}

Example output

sh: 1: cannot create /dev/null: Permission denied
Warning messages:
1: In gdal_setInstallation() :
  No GDAL installation found. Please install 'gdal' before continuing:
	- www.gdal.org (no HDF4 support!)
	- www.trac.osgeo.org/osgeo4w/ (with HDF4 support RECOMMENDED)
	- www.fwtools.maptools.org (with HDF4 support)

2: In gdal_setInstallation() : If you think GDAL is installed, please run:
gdal_setInstallation(ignore.full_scan=FALSE)

gdalUtils documentation built on April 30, 2020, 3 p.m.