polygon order `Error: Polygon with clockwise exterior ring:`

[beausoleilmo]

I used a custom polygon in rgbif::occ_download and got this error

pol_wkt = "POLYGON ((-80.43372 47.0636, -79.81893 52.32097, -80.92362 54.72415, -77.77697 56.47879, -79.87082 58.54605, -79.32995 62.70702, -72.96321 63.06364, -68.36592 61.4554, -67.4021 59.34233, -65.65498 60.91404, -63.60196 60.7996, -62.17351 58.8368, -62.17406 55.19059, -63.23293 54.00381, -66.31831 54.06506, -65.16292 53.0203, -63.65638 53.62978, -58.17867 53.37907, -55.83661 52.0045, -60.70562 46.36289, -62.5469 46.18651, -64.336 47.45411, -66.34416 47.35701, -68.86137 46.63709, -70.35774 44.65409, -74.17295 44.31865, -79.22104 45.75107, -80.43372 47.0636))"

download_key <- rgbif::occ_download(
  rgbif::pred(key = "OCCURRENCE_STATUS", value = "present"),
  rgbif::pred_in(key = "BASIS_OF_RECORD", 
                 value = c("MACHINE_OBSERVATION", "HUMAN_OBSERVATION")),
  rgbif::pred_within(
    value = pol_wkt
  ),
  format = "SIMPLE_PARQUET"
)

Error: Polygon with clockwise exterior ring: POLYGON (([...]))

But this makes it work.

pol_wkt =   pol_wkt |> 
  sf::st_geometry() |>
  sf::st_make_valid() |>
  # Pts polygon 'CW' clockwise.
  lwgeom::st_force_polygon_cw() |>
  st_reverse() |> 
    # GBIF requires CRS epsg:4326 (WGS 84, latitude + longitude) 
    st_transform(crs = 4326) |> 
    # text only
    sf::st_as_text()

Should this be included in the function to make it easier when providing a polygon ?

packageVersion("rgbif")
[1] ‘3.8.1’

Might be related to this : #712

[jhnwllr]

@beausoleilmo this clockwise polygon issue is well known. We could perhaps improve the handling of these polygon issues with downloads in general, since it is common problem.