R/estima_dc2.R

In PabloMBooster/vmsR: For analysing VMS data

estima_dc2 <- function(lon, lat, polygon = NULL){

  require(sf)

    # convert to sf and project on a projected coord system
    area <- st_as_sfc(polygon, crs = 4326L)
    area <- st_set_crs(area, 4326L)
    # points with long/lat coords
    pnts <-
      data.frame(
        long = lon,
        lat = lat
      )

    # convert to sf with the same crs
    pnts_sf <- st_as_sf(pnts, crs = 4326L, coords = c("long", "lat"))
    pnts_sf = st_set_crs(pnts_sf, 4326L)

    # check if crs are equal
    all.equal(st_crs(pnts_sf),st_crs(area))
    output = as.numeric(st_distance(pnts_sf, area)*0.000539957)

  return(output)
}