R/simulate_coordinates.R

In stefmue/georefum: Processing and Linking of Spatial Data Within the GeorefUm Project at GESIS

# simulate_coordinates.R
#' Simulate coordinates
#'@param mun.N Number of municipalties that should be sampled
#'@param resp.N Number of respondents that should be sampled within the already
#'sampled municipalities
#'@export

simulate_coordinates <- function(mun.N = 100,
                                 resp.N = 100,
                                 mun = "") {

  # load census shape for sampling ---------------------------------------------
  data(census.shapes)

  # case: pure random sample ---------------------------------------------------
  if (mun == "") {

    # draw random sample of municipalities -------------------------------------
    municipalities.random <- sp::rbind.SpatialPolygonsDataFrame(
      census.shapes$municipalities[
        sample(nrow(census.shapes$municipalities), mun.N),]#,
      #census.shapes$municipalities[
      #  census.shapes$municipalities@data$GEN == "Köln" |
      #    census.shapes$municipalities@data$GEN == "München",]
      )

    # draw random sample of random municipalities ------------------------------
    for (i in 1:nrow(municipalities.random)) {

      # check whether coordinates object already exists ------------------------
      if (!exists("k")) {

        # draw sample ----------------------------------------------------------
        k <- sp::spsample(municipalities.random[i,], 100, type = "random")
      }

      # if coordinates object already exists -----------------------------------
      else {

        # draw sample ----------------------------------------------------------
        k <- sp::rbind.SpatialPoints(k, sp::spsample(municipalities.random[i,],
                                                     100, type = "random"))
      }
    }
  }

  # case: random sample from selected municipalities ---------------------------
  else {

    for (i in 1:length(mun)) {
      print(mun[i])
      if (!exists("municipalities.random")) {
        municipalities.random <- census.shapes$municipalities[
          census.shapes$municipalities@data$GEN == mun[i],]
      } else {
        municipalities.random <- sp::rbind.SpatialPolygonsDataFrame(
          municipalities.random,
          census.shapes$municipalities[
            census.shapes$municipalities@data$GEN == mun[i],])
      }
    }

    # draw random sample of random municipalities ------------------------------
    for (i in 1:nrow(municipalities.random)) {

      # check whether coordinates object already exists ------------------------
      if (!exists("k")) {

        # draw sample ----------------------------------------------------------
        k <- sp::spsample(municipalities.random[i,], 100, type = "random")
      }

      # if coordinates object already exists -----------------------------------
      else {

        # draw sample ----------------------------------------------------------
        k <- sp::rbind.SpatialPoints(k, sp::spsample(municipalities.random[i,],
                                                     100, type = "random"))
      }
    }
  }

  # assign random id to every case ---------------------------------------------
  #data(key.dat)

  k <- sp::SpatialPointsDataFrame(coords = k@coords,
                                  data = as.data.frame(stringr::str_pad(
                                    sample(1:(mun.N * resp.N), (mun.N * resp.N),
                                           replace = FALSE),
                                    nchar((mun.N * resp.N)), pad = "0")),
                                  proj4string = sp::CRS('+init=epsg:3035'))
  names(k) <- "id2"

  # remove no longer needed internal datasets ----------------------------------
  #if (exists("key.dat")) {
  #  rm("key.dat", envir = globalenv())
  #}
  if(exists("census.shapes")) {
    rm("census.shapes", envir = globalenv())
  }

  # return object --------------------------------------------------------------
  return(k)
}