public GeoHashQuery JoinWith(GeoHashQuery other)
{
if (other.IsPrefix(this))
{
return(new GeoHashQuery(_startValue, other._endValue));
}
if (IsPrefix(other))
{
return(new GeoHashQuery(other._startValue, _endValue));
}
if (IsSuperQuery(other))
{
return(other);
}
if (other.IsSuperQuery(this))
{
return(this);
}
throw new ArgumentException("Can't join these 2 queries: " + this + ", " + other);
}
public static HashSet <GeoHashQuery> QueriesAtLocation(GeoPoint location, double radius)
{
var queryBits = Math.Max(1, Utils.BitsForBoundingBox(location, radius));
var geoHashPrecision = (int)Math.Ceiling((float)queryBits / Base32Utils.BitsPerBase32Char);
var latitude = location.Latitude;
var longitude = location.Longitude;
var latitudeDegrees = radius / Constants.MetersPerDegreeLatitude;
var latitudeNorth = Math.Min(90, latitude + latitudeDegrees);
var latitudeSouth = Math.Max(-90, latitude - latitudeDegrees);
var longitudeDeltaNorth = GeoUtils.DistanceToLongitudeDegrees(radius, latitudeNorth);
var longitudeDeltaSouth = GeoUtils.DistanceToLongitudeDegrees(radius, latitudeSouth);
var longitudeDelta = Math.Max(longitudeDeltaNorth, longitudeDeltaSouth);
var queries = new HashSet <GeoHashQuery>();
var geoHash = new GeoHash(latitude, longitude, geoHashPrecision);
var geoHashW = new GeoHash(latitude, GeoUtils.WrapLongitude(longitude - longitudeDelta), geoHashPrecision);
var geoHashE = new GeoHash(latitude, GeoUtils.WrapLongitude(longitude + longitudeDelta), geoHashPrecision);
var geoHashN = new GeoHash(latitudeNorth, longitude, geoHashPrecision);
var geoHashNw = new GeoHash(latitudeNorth, GeoUtils.WrapLongitude(longitude - longitudeDelta), geoHashPrecision);
var geoHashNE = new GeoHash(latitudeNorth, GeoUtils.WrapLongitude(longitude + longitudeDelta), geoHashPrecision);
var geoHashS = new GeoHash(latitudeSouth, longitude, geoHashPrecision);
var geoHashSW = new GeoHash(latitudeSouth, GeoUtils.WrapLongitude(longitude - longitudeDelta), geoHashPrecision);
var geoHashSE = new GeoHash(latitudeSouth, GeoUtils.WrapLongitude(longitude + longitudeDelta), geoHashPrecision);
queries.Add(QueryForGeoHash(geoHash, queryBits));
queries.Add(QueryForGeoHash(geoHashE, queryBits));
queries.Add(QueryForGeoHash(geoHashW, queryBits));
queries.Add(QueryForGeoHash(geoHashN, queryBits));
queries.Add(QueryForGeoHash(geoHashNE, queryBits));
queries.Add(QueryForGeoHash(geoHashNw, queryBits));
queries.Add(QueryForGeoHash(geoHashS, queryBits));
queries.Add(QueryForGeoHash(geoHashSE, queryBits));
queries.Add(QueryForGeoHash(geoHashSW, queryBits));
// Join queries
bool didJoin;
do
{
GeoHashQuery query1 = null;
GeoHashQuery query2 = null;
foreach (var query in queries)
{
foreach (var other in queries.Where(other => query != other && query.CanJoinWith(other)))
{
query1 = query;
query2 = other;
break;
}
}
if (query1 != null && query2 != null)
{
queries.Remove(query1);
queries.Remove(query2);
queries.Add(query1.JoinWith(query2));
didJoin = true;
}
else
{
didJoin = false;
}
} while (didJoin);
return(queries);
}
protected bool Equals(GeoHashQuery other)
{
return(_startValue == other._startValue && _endValue == other._endValue);
}
public bool CanJoinWith(GeoHashQuery other)
{
return(IsPrefix(other) || other.IsPrefix(this) || IsSuperQuery(other) || other.IsSuperQuery(this));
}
private bool IsSuperQuery(GeoHashQuery other)
{
var startCompare = Compare(other._startValue, this._startValue, StringComparison.Ordinal);
return(startCompare <= 0 && Compare(other._endValue, this._endValue, StringComparison.Ordinal) >= 0);
}
private bool IsPrefix(GeoHashQuery other)
{
return(Compare(other._endValue, this._startValue, StringComparison.Ordinal) >= 0 &&
Compare(other._startValue, this._startValue, StringComparison.Ordinal) < 0 &&
Compare(other._endValue, this._endValue, StringComparison.Ordinal) < 0);
}
