pub fn h3ids(lat: u64, lng: u64) -> Vec<String> {
  let geocoord = GeoCoord {
    lat: degs_to_rads((lat as f64) / 10_000_000f64),
    lon: degs_to_rads((lng as f64) / 10_000_000f64),
  };
  let mut ostream = vec![format!("{}-{}", 0, 0)];
  for resolution in 1..8 {
    let index = geo_to_h3(&geocoord, resolution - 1).unwrap();
    ostream.push(format!("{}-{}", resolution, index));
  }
  return ostream;
}