geohashQueryBounds method

List<List<String>> geohashQueryBounds(GeoPoint center, double radius)

Calculates a set of query bounds to fully contain a given circle, each being a start, end pair where any geohash is guaranteed to be lexicographically larger than start and smaller than end.

@param center The center given as latitude, longitude pair. @param radius The radius of the circle. @return An array of geohash query bounds, each containing a start, end pair.

Implementation

List<List<String>> geohashQueryBounds(GeoPoint center, double radius) {
  validateLocation(center);
  int queryBits = max(1, boundingBoxBits(center, radius));
  var geohashPrecision = (queryBits / _BITS_PER_CHAR).ceil();
  var coordinates = boundingBoxCoordinates(center, radius);
  var queries = coordinates.map((coordinate) {
    return geohashQuery(
            geoHashForLocation(coordinate, precision: geohashPrecision),
            queryBits)
        .toList();
  });
  List<List<String>> filteredList = [];
  var tempList =
      queries.toList().map((e) => e.toString()).toList().toSet().toList();
  for (int i = 0; i < tempList.length; i++) {
    filteredList.add([
      tempList[i].split(',')[0].replaceAll('[', '').trim(),
      tempList[i].split(',')[1].replaceAll(']', '').trim()
    ]);
  }
  return filteredList;
}