`seegSDM::nearestLand()` does not permit lon/lat coordinates

[edwardlavender]

I am just leaving this comment here for others that are interested in taking advantage of this package - I appreciate it is not necessarily designed for wider use though. I noticed that seegSDM::nearestLand() assumes planar coordinates. It would be very helpful to add this to the documentation. Alternatively, you could consider tweaking the function to enable correct geodesic distance calculations, e.g.,:

nearestLand2 <- 
  function(points, raster, max_distance, lonlat) {
    nearest <- function(lis, raster) {
      neighbours <- matrix(lis[[1]], ncol = 2)
      point <- lis[[2]]
      land <- !is.na(neighbours[, 2])
      if (!any(land)) {
        return(c(NA, NA))
      }
      else {
        coords <- raster::xyFromCell(raster, neighbours[land, 1])
        if (nrow(coords) == 1) {
          return(coords[1, ])
        }
        # Use raster::pointDistance() or a related function to permit lon/lat distance calculations 
        dists <- raster::pointDistance(coords, cbind(point[1], point[2]), lonlat = lonlat)
        return(coords[which.min(dists), ])
      }
    }
    neighbour_list <- raster::extract(raster, points, buffer = max_distance, 
                                      cellnumbers = TRUE)
    neighbour_list <- lapply(1:nrow(points), function(i) {
      list(neighbours = neighbour_list[[i]], point = as.numeric(points[i, 
      ]))
    })
    return(t(sapply(neighbour_list, nearest, raster)))
  }