gdalUtils (version 2.0.3.2)

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 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.

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

# NOT RUN {
# 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)
}
# }