mosaic_rasters: Mosaic raster files using GDAL Utilities

Description Usage Arguments Details Value Author(s) See Also Examples

View source: R/mosaic_rasters.R

Description

Mosaic raster files using GDAL Utilities

Usage

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mosaic_rasters(gdalfile, dst_dataset, output.vrt = NULL,
  output_Raster = FALSE, separate = FALSE, trim_margins = NULL,
  gdalwarp_index = 1, gdalwarp_params = list(r = "near"), force_ot = NULL,
  verbose = FALSE, ...)

Arguments

gdalfile

Character. Input files (as a character vector) or a wildcard search term (e.g. "*.tif")

dst_dataset

Character. The destination file name.

output.vrt

Character. Output VRT file. If NULL a temporary .vrt file will be created.

output_Raster

Logical. Return output dst_dataset as a RasterBrick?

separate

Logical. (starting with GDAL 1.7.0) Place each input file into a separate stacked band. Unlike gdalbuildvrt, the full stack is placed in the mosaic, not just the first band.

trim_margins

Numeric. Pre-crop the input tiles by a fixed number of pixels before mosaicking. Can be a single value or four values representing the left, top, right, and bottom margins, respectively.

gdalwarp_index

Numeric. If gdalwarp_index is numeric, the value is used as the index of the gdalfile to match projections and resolutions against when file projections don't match. The default = 1 (the first input file).

gdalwarp_params

List. Set gdalwarp parameters if input file projections don't match. t_srs and tr set here will override those chosen by gdalwarp_index. In general, the only thing you would set here is the resampling algorithm, which defaults to nearest neighbor ("near").

force_ot

Character. ("Byte"/"Int16"/"UInt16"/"UInt32"/"Int32"/"Float32"/"Float64"/"CInt16"/"CInt32"/"CFloat32"/"CFloat64") Forces all bands to be the same datatype. This is helpful if you are using input files of different data types and output formats (e.g. GTiff) that don't support mixed datatypes.

verbose

Logical. Enable verbose execution? Default is FALSE.

...

Parameters to pass to gdalbuildvrt or gdal_translate.

Details

This function mosaics a set of input rasters (gdalfile) using parameters found in gdalbuildvrt and subsequently exports the mosaic to an output file (dst_dataset) using parameters found in gdal_translate. The user can choose to preserve the intermediate output.vrt file, but in general this is not needed.

Value

Either a list of NULLs or a list of RasterBricks depending on whether output_Raster is set to TRUE.

Author(s)

Jonathan A. Greenberg ([email protected])

See Also

gdalbuildvrt, gdal_translate

Examples

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# We'll pre-check to make sure there is a valid GDAL install
# and that raster and rgdal are also installed.
# 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(require(raster) && require(rgdal) && valid_install)
{
layer1 <- system.file("external/tahoe_lidar_bareearth.tif", package="gdalUtils")
layer2 <- system.file("external/tahoe_lidar_highesthit.tif", package="gdalUtils")
mosaic_rasters(gdalfile=c(layer1,layer2),dst_dataset="test_mosaic.envi",separate=TRUE,of="ENVI",
		verbose=TRUE)
gdalinfo("test_mosaic.envi")
}

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)
Loading required package: raster
Loading required package: sp
Loading required package: rgdal
rgdal: version: 1.2-10, (SVN revision 673)
 Geospatial Data Abstraction Library extensions to R successfully loaded
 Loaded GDAL runtime: GDAL 1.10.1, released 2013/08/26
 Path to GDAL shared files: /usr/share/gdal/1.10
 Loaded PROJ.4 runtime: Rel. 4.8.0, 6 March 2012, [PJ_VERSION: 480]
 Path to PROJ.4 shared files: (autodetected)
WARNING: no proj_defs.dat in PROJ.4 shared files
 Linking to sp version: 1.2-3 

gdalUtils documentation built on April 23, 2018, 9:04 a.m.