R/gBufferDS.R

In tombisho/dsGeo: DataSHIELD server side geospatial functions

#'
#' @title Wrapper for gBuffer() function from rgeos package
#' @description This function is a wrapper for the gBuffer() function from the
#' rgeos package
#' @details See the gBuffer() function from rgeos package for more details
#' @param input sp object as defined in package sp
#' @param by_id Logical determining if the function should be applied across subgeometries
#'  (TRUE) or the entire object (FALSE)
#' @param ip_width Distance from original geometry to include in the new geometry.
#'  Negative values are allowed. Either a numeric vector of length 1 when byid is
#'  FALSE; if byid is TRUE: of length 1 replicated to the number of input
#'  geometries, or of length equal to the number of input geometries
#' @return SpatialPolygons (or a SpatialPolygonsDataFrame if by_id=TRUE and
#' input has a data.frame); if negative width(s) lead the object to disappear,
#' NULL is returned for by_id FALSE, and component Polygons objects are dropped if
#' empty for byid TRUE; the SpatialPolygonsDataFrame is subsetted by row.names or id
#' if given to retain non-empty geometry rows
#' @author Bishop, T.
#' @export
#'

gBufferDS <- function(input,by_id=FALSE,ip_width){

  #require(rgeos)

  if(!is.null(input)){
    sdf <- get(input, envir = parent.frame())
  }else{
    sdf <- NULL
  }

  temp <- rgeos::gBuffer(sdf, byid=by_id, width=ip_width)
  return(temp)

}