R/convertRasterLayerToSmoof.R

In jakob-r/geo2smoof: Geo2Smoof converts Elevation Informations to Smoof Functions

#' @title Converts a Raster Layer to Single Objective Function
#' @description Takes the altitude informations from a RasterLayer Object as an objective for a smoof function.
#' @param raster.layer [\code{raster::RasterLayer}]
#' @param maximize [\code{logical(1)}]
#' @param use.constraint.fn [\code{logical(1)}]
#'   If \code{TRUE} the \code{smoof} function will also have a constraint function that returns \code{FALSE} for all input coordinates that are outside of the region coverd in the \code{raster.layer}.
#'   Otherwise the function will just return \code{NA} there.
#' @param interpolate [\code{logical(1)}]
#'   Elevation information for this type of data is just available for integer coordinates.
#'   If \code{interpolate} is \code{TRUE} the function will round the input and return the elevation for the closest integer coordinate.
#' @return \code{smoof function}
#' @export

convertRasterLayerToSmoof = function(raster.layer, maximize = TRUE, interpolate = TRUE, use.constraint.fn = FALSE) {
  if (is.list(raster.layer)) {
    assertList(raster.layer, types = "RasterLayer")
  } else {
    assertClass(raster.layer, "RasterLayer")
  }
  assertFlag(maximize)
  assertFlag(interpolate)
  assertFlag(use.constraint.fn)

  if (maximize) {
    ref = raster.layer@data@max
  } else {
    ref = raster.layer@data@min
  }
  # opt = which(alt.mat == ref, arr.ind = TRUE)
  ymin = raster.layer@extent@ymin
  ymax = raster.layer@extent@ymax
  xmin = raster.layer@extent@xmin
  xmax = raster.layer@extent@xmax
  ps = makeNumericParamSet('coords', 2, lower = c(xmin, ymin), upper = c(xmax, ymax))
  fn = function(x) {
    if (is.null(dim(x))) {
      coords = t(x)
    } else {
      coords = x
    }
    #coords = coords[,c(2,1),drop = FALSE]
    coords = sp::SpatialPoints(coords = coords)
    raster::extract(raster.layer, coords, method = ifelse(interpolate, "bilinear", "simple"))
  }
  if (!use.constraint.fn) constraint.fn = NULL else {
    constraint.fn = function(x) {!is.na(fn(x))}
  }
  makeSingleObjectiveFunction(name = coalesce(names(raster.layer), 'RasterLayer'), fn = fn, has.simple.signature = TRUE, par.set = ps, constraint.fn = constraint.fn, global.opt.value = ref, minimize = !maximize)
}