encode method

String encode(double longitude, double latitude, { int precision = 12, })

Encodes a given Longitude and Latitude into a String geohash

Implementation

String encode(double longitude, double latitude, {int precision = 12}) {
  bool precisionOdd = precision % 2 == 1;
  int originalPrecision = precision + 0;
  if (longitude < -180.0 || longitude > 180.0) {
    throw RangeError.range(longitude, -180, 180, "Longitude");
  }
  if (latitude < -90.0 || latitude > 90.0) {
    throw RangeError.range(latitude, -90, 90, "Latitude");
  }
  if (precision % 2 == 1) {
    precision = precision + 1;
  }
  if (precision != 1) precision ~/= 2;

  List<int> longitudeBits = _doubleToBits(
      value: longitude, lower: -180.0, upper: 180.0, length: precision * 5);
  List<int> latitudeBits = _doubleToBits(
      value: latitude, lower: -90.0, upper: 90.0, length: precision * 5);

  List<int> ret = [];
  for (int i = 0; i < longitudeBits.length; i++) {
    ret.add(longitudeBits[i]);
    ret.add(latitudeBits[i]);
  }

  String geohashString = _bitsToGeoHash(ret);

  return originalPrecision == 1
      ? geohashString.substring(0, 1)
      : (precisionOdd
          ? geohashString.substring(0, geohashString.length - 1)
          : geohashString);
}