R/project_compare.R

In jhollist/miscPackage: Package with JWHs Miscellaneous Functions

#' Compare projections
#' 
#' Different projections represent the distortions resulting from projection 
#' spatial data in different ways.  This results in variation of basic 
#' measurements that result solely from the projection chosen.  This function
#' compares the resultant area and/or length measurements that result from 
#' different projections.
#' 
#' @param insp An Spatial* object from the \code{sp} package.  Input CRS must
#'             be defined 
#' @param ...  spTransform arguments
#' 
#' @export
project_compare <- function(insp, ...) {
    # Need to test for CRS on insp
    
    # Check units on
    insp2 <- sp::spTransform(insp, ...)
    myList <- list(Original = list(proj = proj4string(insp), area = rgeos::gArea(insp), perim = rgeos::gLength(insp)), 
        Projected = list(proj = proj4string(insp2), area = rgeos::gArea(insp2), perim = rgeos::gLength(insp2)))
    return(myList)
}