gdal_cmd_builder: gdal_cmd_builder

Description

Helper function for building GDAL commands.

Usage

gdal_cmd_builder(executable, parameter_variables = c(),
  parameter_values = c(), parameter_order = c(), parameter_noflags = c(),
  parameter_doubledash = c(), parameter_noquotes = c(),
  gdal_installation_id = 1)

Arguments

executable

Character. The GDAL command to use (e.g. "gdal_translate")

parameter_variables

List. A list of parameter names, organized by type.

parameter_values

List. A list of the parameters names/values.

parameter_order

Character. The order of the parameters for the GDAL command.

parameter_noflags

Character. Parameters which do not have a flag.

parameter_doubledash

Character. Parameters which should have a double dash "--".

parameter_noquotes

Character. Parameters which should not be wrapped in quotes (vector parameters only, at present).

gdal_installation_id

Numeric. The ID of the GDAL installation to use. Defaults to 1.

Value

Formatted GDAL command for use with system() calls.

Details

This function takes the executable name (e.g. "gdal_translate"), a list of parameter names organized by logical, vector, scalar, character, repeatable, a list of values of these parameters, the order they should be used in the GDAL command, and a list of parameters that should not have a flag, and returns a properly formatted GDAL command (with the full path-to-executable) that should work with a system() call.

Sometimes, a user may not want to use the most recent GDAL install (gdal_installation_id=1), so the gdal_installation_id can be used to set a different install. This is often used with gdal_chooseInstallation if, for instance, the particular GDAL installation required needs a specific driver that may not be available in all installations.

In general, an end user shouldn't need to use this function -- it is used by many of the GDAL wrappers within gdalUtils.

References

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

Examples

Run this code

# NOT RUN {
# This builds a gdal_translate command.
executable <- "gdal_translate"

parameter_variables <- list(
			logical = list(
					varnames <- c("strict","unscale","epo",
					"eco","q","sds","stats")),
			vector = list(
					varnames <- c("outsize","scale","srcwin",
					"projwin","a_ullr","gcp")),
			scalar = list(
					varnames <- c("a_nodata")),
			character = list(
					varnames <- c("ot","of","mask","expand","a_srs",
					"src_dataset","dst_dataset")),
			repeatable = list(
					varnames <- c("b","mo","co")))

parameter_order <- c(
			"strict","unscale","epo","eco","q","sds","stats",
			"outsize","scale","srcwin","projwin","a_ullr","gcp",
			"a_nodata",
			"ot","of","mask","expand","a_srs",
			"b","mo","co",
			"src_dataset","dst_dataset")

parameter_noflags <- c("src_dataset","dst_dataset")

# Now assign some parameters:
parameter_values = list(
	src_dataset = "input.tif",
	dst_dataset = "output.envi",
	of = "ENVI",
	strict = TRUE
)

cmd <- gdal_cmd_builder(
			executable=executable,
			parameter_variables=parameter_variables,
			parameter_values=parameter_values,
			parameter_order=parameter_order,
			parameter_noflags=parameter_noflags)

cmd
system(cmd,intern=TRUE) 
# }

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