Class GeoEncodingUtils


  • public final class GeoEncodingUtils
    extends Object
    reusable geopoint encoding methods
    WARNING: This API is experimental and might change in incompatible ways in the next release.
    • Field Detail

      • BITS

        public static final short BITS
        number of bits used for quantizing latitude and longitude values
        See Also:
        Constant Field Values
      • MIN_LON_ENCODED

        public static final int MIN_LON_ENCODED
      • MAX_LON_ENCODED

        public static final int MAX_LON_ENCODED
    • Method Detail

      • encodeLatitude

        public static int encodeLatitude​(double latitude)
        Quantizes double (64 bit) latitude into 32 bits (rounding down: in the direction of -90)
        Parameters:
        latitude - latitude value: must be within standard +/-90 coordinate bounds.
        Returns:
        encoded value as a 32-bit int
        Throws:
        IllegalArgumentException - if latitude is out of bounds
      • encodeLatitudeCeil

        public static int encodeLatitudeCeil​(double latitude)
        Quantizes double (64 bit) latitude into 32 bits (rounding up: in the direction of +90)
        Parameters:
        latitude - latitude value: must be within standard +/-90 coordinate bounds.
        Returns:
        encoded value as a 32-bit int
        Throws:
        IllegalArgumentException - if latitude is out of bounds
      • encodeLongitude

        public static int encodeLongitude​(double longitude)
        Quantizes double (64 bit) longitude into 32 bits (rounding down: in the direction of -180)
        Parameters:
        longitude - longitude value: must be within standard +/-180 coordinate bounds.
        Returns:
        encoded value as a 32-bit int
        Throws:
        IllegalArgumentException - if longitude is out of bounds
      • encodeLongitudeCeil

        public static int encodeLongitudeCeil​(double longitude)
        Quantizes double (64 bit) longitude into 32 bits (rounding up: in the direction of +180)
        Parameters:
        longitude - longitude value: must be within standard +/-180 coordinate bounds.
        Returns:
        encoded value as a 32-bit int
        Throws:
        IllegalArgumentException - if longitude is out of bounds
      • decodeLatitude

        public static double decodeLatitude​(int encoded)
        Turns quantized value from encodeLatitude(double) back into a double.
        Parameters:
        encoded - encoded value: 32-bit quantized value.
        Returns:
        decoded latitude value.
      • decodeLatitude

        public static double decodeLatitude​(byte[] src,
                                            int offset)
        Turns quantized value from byte array back into a double.
        Parameters:
        src - byte array containing 4 bytes to decode at offset
        offset - offset into src to decode from.
        Returns:
        decoded latitude value.
      • decodeLongitude

        public static double decodeLongitude​(int encoded)
        Turns quantized value from encodeLongitude(double) back into a double.
        Parameters:
        encoded - encoded value: 32-bit quantized value.
        Returns:
        decoded longitude value.
      • decodeLongitude

        public static double decodeLongitude​(byte[] src,
                                             int offset)
        Turns quantized value from byte array back into a double.
        Parameters:
        src - byte array containing 4 bytes to decode at offset
        offset - offset into src to decode from.
        Returns:
        decoded longitude value.
      • createDistancePredicate

        public static GeoEncodingUtils.DistancePredicate createDistancePredicate​(double lat,
                                                                                 double lon,
                                                                                 double radiusMeters)
        Create a predicate that checks whether points are within a distance of a given point. It works by computing the bounding box around the circle that is defined by the given points/distance and splitting it into between 1024 and 4096 smaller boxes (4096*0.75^2=2304 on average). Then for each sub box, it computes the relation between this box and the distance query. Finally at search time, it first computes the sub box that the point belongs to, most of the time, no distance computation will need to be performed since all points from the sub box will either be in or out of the circle.
        NOTE: This API is for internal purposes only and might change in incompatible ways in the next release.