Class ShapeField


  • public final class ShapeField
    extends java.lang.Object
    A base shape utility class used for both LatLon (spherical) and XY (cartesian) shape fields.

    Polygon's and Line's are decomposed into a triangular mesh using the Tessellator utility class. Each ShapeField.Triangle is encoded by this base class and indexed as a seven dimension multi-value field.

    Finding all shapes that intersect a range (e.g., bounding box), or target shape, at search time is efficient.

    This class defines the static methods for encoding the three vertices of a tessellated triangles as a seven dimension point. The coordinates are converted from double precision values into 32 bit integers so they are sortable at index time.

    • Field Detail

      • BYTES

        static final int BYTES
        vertex coordinates are encoded as 4 byte integers
        See Also:
        Constant Field Values
      • TYPE

        protected static final FieldType TYPE
        tessellated triangles are seven dimensions; the first four are the bounding box index dimensions
      • MINY_MINX_MAXY_MAXX_Y_X

        private static final int MINY_MINX_MAXY_MAXX_Y_X
        See Also:
        Constant Field Values
      • MINY_MINX_Y_X_MAXY_MAXX

        private static final int MINY_MINX_Y_X_MAXY_MAXX
        See Also:
        Constant Field Values
      • MAXY_MINX_Y_X_MINY_MAXX

        private static final int MAXY_MINX_Y_X_MINY_MAXX
        See Also:
        Constant Field Values
      • MAXY_MINX_MINY_MAXX_Y_X

        private static final int MAXY_MINX_MINY_MAXX_Y_X
        See Also:
        Constant Field Values
      • Y_MINX_MINY_X_MAXY_MAXX

        private static final int Y_MINX_MINY_X_MAXY_MAXX
        See Also:
        Constant Field Values
      • Y_MINX_MINY_MAXX_MAXY_X

        private static final int Y_MINX_MINY_MAXX_MAXY_X
        See Also:
        Constant Field Values
      • MAXY_MINX_MINY_X_Y_MAXX

        private static final int MAXY_MINX_MINY_X_Y_MAXX
        See Also:
        Constant Field Values
      • MINY_MINX_Y_MAXX_MAXY_X

        private static final int MINY_MINX_Y_MAXX_MAXY_X
        See Also:
        Constant Field Values
    • Constructor Detail

      • ShapeField

        private ShapeField()
    • Method Detail

      • encodeTriangle

        public static void encodeTriangle​(byte[] bytes,
                                          int aY,
                                          int aX,
                                          boolean ab,
                                          int bY,
                                          int bX,
                                          boolean bc,
                                          int cY,
                                          int cX,
                                          boolean ca)
        A triangle is encoded using 6 points and an extra point with encoded information in three bits of how to reconstruct it. Triangles are encoded with CCW orientation and might be rotated to limit the number of possible reconstructions to 2^3. Reconstruction always happens from west to east.