R/fix_extent.R

In spatial.tools: R Functions for Working with Spatial Data

#' Forces a list of Raster*s to all have the same extent.
#' @param extent_reference Raster*. A Raster* object that will provide the extent to all the other Raster*s.  If unassigned, will assume it is the first Raster* in the broken_extents list. 
#' @param broken_extents list of Raster* objects. Raster* objects that will be coerced to the extent_reference's extent.
#' @author Jonathan A. Greenberg (\email{spatial.tools@@estarcion.net})
#' @seealso \code{\link{extent}},\code{\link{stack}}
#' 
#' @examples
#' library("raster")
#' tahoe_highrez <- brick(system.file("external/tahoe_highrez.tif", package="spatial.tools"))
#' tahoe_highrez
#' tahoe_highrez_broken <- tahoe_highrez
#' # We'll "break" the extent:
#' extent(tahoe_highrez_broken) <- c(0,360,-90,90)
#' tahoe_highrez_broken
#' tahoe_highrez_fixed <- fix_extent(tahoe_highrez,tahoe_highrez_broken)
#' tahoe_highrez_fixed
#' 
#' @import raster
#' @export


fix_extent <- function(extent_reference,broken_extents)
{
	if(missing(extent_reference))
	{
		extent_reference = broken_extents[[1]]
	}
	if(class(broken_extents) != "list") broken_extents <- list(broken_extents)
	
	base_extent=extent(extent_reference)
	fixed_extents=mapply(
		function(x,base_extent) 
		{ 
			extent(x)=base_extent
			return(x)
		},broken_extents,MoreArgs=list(base_extent=base_extent) 
	)
	return(fixed_extents)
}