Package org.locationtech.jts.geom

Class Polygon

  • All Implemented Interfaces:
    Serializable, Cloneable, Comparable, Polygonal
    public class Polygon
extends Geometry
implements Polygonal
    Represents a polygon with linear edges, which may include holes. The outer boundary (shell) and inner boundaries (holes) of the polygon are represented by LinearRings. The boundary rings of the polygon may have any orientation. Polygons are closed, simple geometries by definition.

    The polygon model conforms to the assertions specified in the OpenGIS Simple Features Specification for SQL.

    A Polygon is topologically valid if and only if:

    • the coordinates which define it are valid coordinates
    • the linear rings for the shell and holes are valid (i.e. are closed and do not self-intersect)
    • holes touch the shell or another hole at at most one point (which implies that the rings of the shell and holes must not cross)
    • the interior of the polygon is connected, or equivalently no sequence of touching holes makes the interior of the polygon disconnected (i.e. effectively split the polygon into two pieces).
    Version:
    1.7
    See Also:
    Serialized Form

    • Field Detail

      • shell

        protected LinearRing shell
        The exterior boundary, or null if this Polygon is empty.

      • holes

        protected LinearRing[] holes
        The interior boundaries, if any. This instance var is never null. If there are no holes, the array is of zero length.

    • Constructor Detail

      • Polygon

        public Polygon​(LinearRing shell,
               PrecisionModel precisionModel,
               int SRID)
        Deprecated.
        Use GeometryFactory instead
        Constructs a Polygon with the given exterior boundary.
        Parameters:
        shell - the outer boundary of the new Polygon, or null or an empty LinearRing if the empty geometry is to be created.
        precisionModel - the specification of the grid of allowable points for this Polygon
        SRID - the ID of the Spatial Reference System used by this Polygon

      • Polygon

        public Polygon​(LinearRing shell,
               LinearRing[] holes,
               PrecisionModel precisionModel,
               int SRID)
        Deprecated.
        Use GeometryFactory instead
        Constructs a Polygon with the given exterior boundary and interior boundaries.
        Parameters:
        shell - the outer boundary of the new Polygon, or null or an empty LinearRing if the empty geometry is to be created.
        holes - the inner boundaries of the new Polygon , or null or empty LinearRings if the empty geometry is to be created.
        precisionModel - the specification of the grid of allowable points for this Polygon
        SRID - the ID of the Spatial Reference System used by this Polygon

      • Polygon

        public Polygon​(LinearRing shell,
               LinearRing[] holes,
               GeometryFactory factory)
        Constructs a Polygon with the given exterior boundary and interior boundaries.
        Parameters:
        shell - the outer boundary of the new Polygon, or null or an empty LinearRing if the empty geometry is to be created.
        holes - the inner boundaries of the new Polygon , or null or empty LinearRings if the empty geometry is to be created.

    • Method Detail

      • getCoordinate

        public Coordinate getCoordinate()
        Description copied from class: Geometry
        Returns a vertex of this Geometry (usually, but not necessarily, the first one). The returned coordinate should not be assumed to be an actual Coordinate object used in the internal representation.
        Specified by:
        getCoordinate in class Geometry
        Returns:
        a Coordinate which is a vertex of this Geometry.

      • getNumPoints

        public int getNumPoints()
        Description copied from class: Geometry
        Returns the count of this Geometrys vertices. The Geometry s contained by composite Geometrys must be Geometry's; that is, they must implement getNumPoints
        Specified by:
        getNumPoints in class Geometry
        Returns:
        the number of vertices in this Geometry

      • getDimension

        public int getDimension()
        Description copied from class: Geometry
        Returns the dimension of this geometry. The dimension of a geometry is is the topological dimension of its embedding in the 2-D Euclidean plane. In the JTS spatial model, dimension values are in the set {0,1,2}.

        Note that this is a different concept to the dimension of the vertex Coordinates. The geometry dimension can never be greater than the coordinate dimension. For example, a 0-dimensional geometry (e.g. a Point) may have a coordinate dimension of 3 (X,Y,Z).

        Specified by:
        getDimension in class Geometry
        Returns:
        the topological dimension of this geometry.

      • getBoundaryDimension

        public int getBoundaryDimension()
        Description copied from class: Geometry
        Returns the dimension of this Geometrys inherent boundary.
        Specified by:
        getBoundaryDimension in class Geometry
        Returns:
        the dimension of the boundary of the class implementing this interface, whether or not this object is the empty geometry. Returns Dimension.FALSE if the boundary is the empty geometry.

      • isEmpty

        public boolean isEmpty()
        Description copied from class: Geometry
        Tests whether the set of points covered by this Geometry is empty.
        Specified by:
        isEmpty in class Geometry
        Returns:
        true if this Geometry does not cover any points

      • isRectangle

        public boolean isRectangle()
        Tests if a valid polygon is simple. This method always returns true, since a valid polygon is always simple
        Overrides:
        isRectangle in class Geometry
        Returns:
        true

      • getExteriorRing

        public LineString getExteriorRing()

      • getNumInteriorRing

        public int getNumInteriorRing()

      • getInteriorRingN

        public LineString getInteriorRingN​(int n)

      • getGeometryType

        public String getGeometryType()
        Description copied from class: Geometry
        Returns the name of this Geometry's actual class.
        Specified by:
        getGeometryType in class Geometry
        Returns:
        the name of this Geometrys actual class

      • getArea

        public double getArea()
        Returns the area of this Polygon
        Overrides:
        getArea in class Geometry
        Returns:
        the area of the polygon

      • getLength

        public double getLength()
        Returns the perimeter of this Polygon
        Overrides:
        getLength in class Geometry
        Returns:
        the perimeter of the polygon

      • computeEnvelopeInternal

        protected Envelope computeEnvelopeInternal()
        Description copied from class: Geometry
        Returns the minimum and maximum x and y values in this Geometry , or a null Envelope if this Geometry is empty. Unlike getEnvelopeInternal, this method calculates the Envelope each time it is called; getEnvelopeInternal caches the result of this method.
        Specified by:
        computeEnvelopeInternal in class Geometry
        Returns:
        this Geometrys bounding box; if the Geometry is empty, Envelope#isNull will return true

      • equalsExact

        public boolean equalsExact​(Geometry other,
                           double tolerance)
        Description copied from class: Geometry
        Returns true if the two Geometrys are exactly equal, up to a specified distance tolerance. Two Geometries are exactly equal within a distance tolerance if and only if:
        • they have the same structure
        • they have the same values for their vertices, within the given tolerance distance, in exactly the same order.
        This method does not test the values of the GeometryFactory, the SRID, or the userData fields.

        To properly test equality between different geometries, it is usually necessary to Geometry.normalize() them first.

        Specified by:
        equalsExact in class Geometry
        Parameters:
        other - the Geometry with which to compare this Geometry
        tolerance - distance at or below which two Coordinates are considered equal
        Returns:
        true if this and the other Geometry have identical structure and point values, up to the distance tolerance.
        See Also:
        Geometry.equalsExact(Geometry), Geometry.normalize(), Geometry.norm()

      • apply

        public void apply​(CoordinateFilter filter)
        Description copied from class: Geometry
        Performs an operation with or on this Geometry's coordinates. If this method modifies any coordinate values, Geometry.geometryChanged() must be called to update the geometry state. Note that you cannot use this method to modify this Geometry if its underlying CoordinateSequence's #get method returns a copy of the Coordinate, rather than the actual Coordinate stored (if it even stores Coordinate objects at all).
        Specified by:
        apply in class Geometry
        Parameters:
        filter - the filter to apply to this Geometry's coordinates

      • apply

        public void apply​(GeometryFilter filter)
        Description copied from class: Geometry
        Performs an operation with or on this Geometry and its subelement Geometrys (if any). Only GeometryCollections and subclasses have subelement Geometry's.
        Specified by:
        apply in class Geometry
        Parameters:
        filter - the filter to apply to this Geometry (and its children, if it is a GeometryCollection).

      • apply

        public void apply​(GeometryComponentFilter filter)
        Description copied from class: Geometry
        Performs an operation with or on this Geometry and its component Geometry's. Only GeometryCollections and Polygons have component Geometry's; for Polygons they are the LinearRings of the shell and holes.
        Specified by:
        apply in class Geometry
        Parameters:
        filter - the filter to apply to this Geometry.

      • clone

        public Object clone()
        Deprecated.
        Creates and returns a full copy of this Polygon object. (including all coordinates contained by it).
        Overrides:
        clone in class Geometry
        Returns:
        a clone of this instance

      • copyInternal

        protected Polygon copyInternal()
        Description copied from class: Geometry
        An internal method to copy subclass-specific geometry data.
        Specified by:
        copyInternal in class Geometry
        Returns:
        a copy of the target geometry object.

      • convexHull

        public Geometry convexHull()
        Description copied from class: Geometry
        Computes the smallest convex Polygon that contains all the points in the Geometry. This obviously applies only to Geometry s which contain 3 or more points; the results for degenerate cases are specified as follows:
        Number of Points in argument Geometry Geometry class of result
        0 empty GeometryCollection
        1 Point
        2 LineString
        3 or more Polygon
        Overrides:
        convexHull in class Geometry
        Returns:
        the minimum-area convex polygon containing this Geometry' s points

      • normalize

        public void normalize()
        Description copied from class: Geometry
        Converts this Geometry to normal form (or canonical form ). Normal form is a unique representation for Geometry s. It can be used to test whether two Geometrys are equal in a way that is independent of the ordering of the coordinates within them. Normal form equality is a stronger condition than topological equality, but weaker than pointwise equality. The definitions for normal form use the standard lexicographical ordering for coordinates. "Sorted in order of coordinates" means the obvious extension of this ordering to sequences of coordinates.

        NOTE that this method mutates the value of this geometry in-place. If this is not safe and/or wanted, the geometry should be cloned prior to normalization.

        Specified by:
        normalize in class Geometry

      • compareToSameClass

        protected int compareToSameClass​(Object o)
        Description copied from class: Geometry
        Returns whether this Geometry is greater than, equal to, or less than another Geometry having the same class.
        Specified by:
        compareToSameClass in class Geometry
        Parameters:
        o - a Geometry having the same class as this Geometry
        Returns:
        a positive number, 0, or a negative number, depending on whether this object is greater than, equal to, or less than o, as defined in "Normal Form For Geometry" in the JTS Technical Specifications

      • compareToSameClass

        protected int compareToSameClass​(Object o,
                                 CoordinateSequenceComparator comp)
        Description copied from class: Geometry
        Returns whether this Geometry is greater than, equal to, or less than another Geometry of the same class. using the given CoordinateSequenceComparator.
        Specified by:
        compareToSameClass in class Geometry
        Parameters:
        o - a Geometry having the same class as this Geometry
        comp - a CoordinateSequenceComparator
        Returns:
        a positive number, 0, or a negative number, depending on whether this object is greater than, equal to, or less than o, as defined in "Normal Form For Geometry" in the JTS Technical Specifications

      • reverse

        public Geometry reverse()
        Description copied from class: Geometry
        Computes a new geometry which has all component coordinate sequences in reverse order (opposite orientation) to this one.
        Specified by:
        reverse in class Geometry
        Returns:
        a reversed geometry