com.vividsolutions.jts.operation

Class IsSimpleOp


  • public class IsSimpleOp
extends Object
    Tests whether a Geometry is simple. In general, the SFS specification of simplicity follows the rule:
    • A Geometry is simple if and only if the only self-intersections are at boundary points.

    Simplicity is defined for each Geometry type as follows:

    • Polygonal geometries are simple by definition, so isSimple trivially returns true. (Note: this means that isSimple cannot be used to test for (invalid) self-intersections in Polygons. In order to check if a Polygonal geometry has self-intersections, use Geometry.isValid()).
    • Linear geometries are simple iff they do not self-intersect at interior points (i.e. points other than boundary points). This is equivalent to saying that no two linear components satisfy the SFS Geometry.touches(Geometry) predicate.
    • Zero-dimensional (point) geometries are simple if and only if they have no repeated points.
    • Empty geometries are always simple, by definition
    For Lineal geometries the evaluation of simplicity can be customized by supplying a BoundaryNodeRule to define how boundary points are determined. The default is the SFS-standard BoundaryNodeRule.MOD2_BOUNDARY_RULE. Note that under the Mod-2 rule, closed LineStrings (rings) will never satisfy the touches predicate at their endpoints, since these are interior points, not boundary points. If it is required to test whether a set of LineStrings touch only at their endpoints, use IsSimpleOp with BoundaryNodeRule.ENDPOINT_BOUNDARY_RULE. For example, this can be used to validate that a set of lines form a topologically valid linear network.
    See Also:
    BoundaryNodeRule

    • Constructor Detail

      • IsSimpleOp

        public IsSimpleOp()
        Deprecated.  use IsSimpleOp(Geometry)
        Creates a simplicity checker using the default SFS Mod-2 Boundary Node Rule

      • IsSimpleOp

        public IsSimpleOp(Geometry geom)
        Creates a simplicity checker using the default SFS Mod-2 Boundary Node Rule
        Parameters:
        geom - the geometry to test

      • IsSimpleOp

        public IsSimpleOp(Geometry geom,
                  BoundaryNodeRule boundaryNodeRule)
        Creates a simplicity checker using a given BoundaryNodeRule
        Parameters:
        geom - the geometry to test
        boundaryNodeRule - the rule to use.

    • Method Detail

      • isSimple

        public boolean isSimple()
        Tests whether the geometry is simple.
        Returns:
        true if the geometry is simple

      • getNonSimpleLocation

        public Coordinate getNonSimpleLocation()
        Gets a coordinate for the location where the geometry fails to be simple. (i.e. where it has a non-boundary self-intersection). isSimple() must be called before this method is called.
        Returns:
        a coordinate for the location of the non-boundary self-intersection or null if the geometry is simple

      • isSimple

        public boolean isSimple(LineString geom)
        Deprecated.  use isSimple()
        Reports whether a LineString is simple.
        Parameters:
        geom - the lineal geometry to test
        Returns:
        true if the geometry is simple

      • isSimple

        public boolean isSimple(MultiLineString geom)
        Deprecated.  use isSimple()
        Reports whether a MultiLineString geometry is simple.
        Parameters:
        geom - the lineal geometry to test
        Returns:
        true if the geometry is simple

      • isSimple

        public boolean isSimple(MultiPoint mp)
        Deprecated.  use isSimple()
        A MultiPoint is simple iff it has no repeated points