Interface S2Shape

    • Method Detail

      • numEdges

        int numEdges()
        Returns the number of edges in this shape.
      • getEdge

        void getEdge​(int index,
                     S2Shape.MutableEdge result)
        Returns the edge for the given index in result. Must not return zero-length edges.
        Parameters:
        index - which edge to set into result, from 0 to numEdges() - 1
      • hasInterior

        boolean hasInterior()
        Returns true if this shape has an interior, i.e. the shape consists of one or more closed non-intersecting loops.
      • containsOrigin

        boolean containsOrigin()
        Returns true if this shape contains S2.origin(). Should return false for shapes that do not have an interior.
      • numChains

        int numChains()
        Returns the number of contiguous edge chains in the shape. For example, a shape whose edges are [AB, BC, CD, AE, EF] may consist of two chains [A, B, C, D] and [A, E, F]. Every chain is assigned a chain id numbered sequentially starting from zero.

        An empty shape has no chains. A full shape (which contains the entire globe) has one chain with no edges. Other shapes should have at least one chain, and the sum of all valid chain lengths should equal numEdges() (that is, edges may only be used by a single chain).

        Note that it is always acceptable to implement this method by returning numEdges() (i.e. every chain consists of a single edge), but this may reduce the efficiency of some algorithms.

      • getChainStart

        int getChainStart​(int chainId)
        Returns the first edge id corresponding to the edge chain for the given chain id. The edge chains must form contiguous, non-overlapping ranges that cover the entire range of edge ids.
        Parameters:
        chainId - which edge chain to return its start, from 0 to numChains() - 1
      • getChainLength

        int getChainLength​(int chainId)
        Returns the number of edge ids corresponding to the edge chain for the given chain id. The edge chains must form contiguous, non-overlapping ranges that cover the entire range of edge ids.
        Parameters:
        chainId - which edge chain to return its length, from 0 to numChains() - 1
      • getChainEdge

        void getChainEdge​(int chainId,
                          int offset,
                          S2Shape.MutableEdge result)
        Returns the edge for the given chain id and offset in result. Must not return zero-length edges.
        Parameters:
        chainId - which chain contains the edge to return, from 0 to numChains() - 1
        offset - position from chain start for the edge to return, from 0 to getChainLength(int) - 1
      • chain

        default java.util.List<S2Point> chain​(int chain)
        Returns a view of the vertices in the given chain. Note 2D shapes omit the last vertex, as it's a duplicate of the first.
      • chains

        default java.util.List<java.util.List<S2Point>> chains()
        Returns a view of the chains in this shape.
      • dimension

        int dimension()
        Returns the dimension of the geometry represented by this shape.
        • 0 - Point geometry. Each point is represented as a degenerate edge.
        • 1 - Polyline geometry. Polyline edges may be degenerate. A shape may represent any number of polylines. Polylines edges may intersect.
        • 2 - Polygon geometry. Edges should be oriented such that the polygon interior is always on the left. In theory the edges may be returned in any order, but typically the edges are organized as a collection of edge chains where each chain represents one polygon loop. Polygons may have degeneracies, e.g., degenerate edges or sibling pairs consisting of an edge and its corresponding reversed edge. A polygon loop may also be full (containing all points on the sphere); by convention this is represented as a chain with no edges.

        Note that this method allows degenerate geometry of different dimensions to be distinguished, e.g., it allows a point to be distinguished from a polyline or polygon that has been simplified to a single point.

      • getReferencePoint

        default S2Shape.ReferencePoint getReferencePoint()
        Returns a point referenced to, i.e. indicating containment by, this shape.