/// <summary>
/// Shortens the full code by removing four or six digits, depending on the provided reference point
/// </summary>
/// <param name="latitude">Reference location latitude</param>
/// <param name="longitude">Reference location longitude</param>
/// <returns>Returns a new Open Location Code with less digits</returns>
public static OpenLocationCode Shorten(this OpenLocationCode code, double latitude, double longitude)
{
if (!code.IsFull)
{
throw new InvalidOperationException("Can only shorten a full Open Location Code.");
}
if (code.IsPadded)
{
throw new InvalidOperationException("Can only shorten an Open Location Code that isn't padded.");
}
Bounds bounds = code.Decode();
double latitudeDiff = Math.Abs(latitude - bounds.CenterLatitude);
double longitudeDiff = Math.Abs(longitude - bounds.CenterLongitude);
if (latitudeDiff < Constants.LatitudePrecision8Digits && longitudeDiff < Constants.LatitudePrecision8Digits)
{
return(new OpenLocationCode(code.Code.Substring(8)));
}
else if (latitudeDiff < Constants.LatitudePrecision6Digits && longitudeDiff < Constants.LatitudePrecision6Digits)
{
return(new OpenLocationCode(code.Code.Substring(6)));
}
else if (latitudeDiff < Constants.LatitudePrecision4Digits && longitudeDiff < Constants.LatitudePrecision4Digits)
{
return(new OpenLocationCode(code.Code.Substring(4)));
}
throw new ArgumentException("Location is too far from the Open Location Code center.");
}
public static OpenLocationCode Recover(this OpenLocationCode code, double latitude, double longitude)
{
if (code.IsFull)
{
return(code);
}
latitude = Builder.ClipLatitude(latitude);
longitude = Builder.NormalizeLongitude(longitude);
int digitsToRecover = 8 - code.Code.IndexOf(Constants.Separator);
double paddedArea = Math.Pow(20, 2 - (digitsToRecover / 2));
// use reference location to pad the supplied code
string prefix = OpenLocationCode.Encode(latitude, longitude)
.Substring(0, digitsToRecover);
var recoveredCode = new OpenLocationCode(prefix + code.Code);
var recoveredCodeBounds = recoveredCode.Decode();
double recoveredLatitude = recoveredCodeBounds.CenterLatitude;
double recoveredLongitude = recoveredCodeBounds.CenterLongitude;
// adjust latitude resolution
double latitudeDiff = recoveredLatitude - latitude;
if (latitudeDiff > (paddedArea / 2))
{
recoveredLatitude -= paddedArea;
}
else if (latitudeDiff < (-paddedArea / 2))
{
recoveredLatitude += paddedArea;
}
// adjust longitude resolution
double longitudeDiff = recoveredLongitude - longitude;
if (longitudeDiff > (paddedArea / 2))
{
recoveredLongitude -= paddedArea;
}
else if (longitudeDiff < (-paddedArea / 2))
{
recoveredLongitude += paddedArea;
}
return(new OpenLocationCode(recoveredLatitude, recoveredLongitude, recoveredCode.Code.Length - 1));
}
/// <summary>
/// Decodes code into object encapsulating latitude/longitude bounding box
/// </summary>
/// <returns>Returns the area boundaries for the provided code</returns>
public static Bounds Decode(this OpenLocationCode code)
{
if (!code.IsFull)
{
throw new InvalidOperationException(string.Format("'{0}' is not a full Open Location Code. Only full codes can be decoded.", code.Code));
}
string decoded = Regex.Replace(code.Code, "[0+]", "");
// Decode the lat/lng pair component.
decimal southLatitude = 0;
decimal westLongitude = 0;
int digit = 0;
double latitudeResolution = 400;
double longitudeResolution = 400;
// Decode pair
while (digit < decoded.Length)
{
if (digit < 10)
{
latitudeResolution /= 20.0;
longitudeResolution /= 20.0;
southLatitude += new decimal(latitudeResolution * Constants.AlphabetIndex[decoded[digit]]);
westLongitude += new decimal(longitudeResolution * Constants.AlphabetIndex[decoded[digit + 1]]);
digit += 2;
}
else
{
latitudeResolution /= 5;
longitudeResolution /= 4;
southLatitude += new decimal(latitudeResolution * (Constants.AlphabetIndex[decoded[digit]] / 4.0));
westLongitude += new decimal(longitudeResolution * (Constants.AlphabetIndex[decoded[digit]] % 4.0));
digit += 1;
}
}
var bounds = new Bounds(
southLatitude - 90
, westLongitude - 180
, (southLatitude - 90) + new decimal(latitudeResolution)
, (westLongitude - 180) + new decimal(longitudeResolution));
return(bounds);
}
