Package org.locationtech.jts.algorithm
Class MinimumDiameter
java.lang.Object
org.locationtech.jts.algorithm.MinimumDiameter
Computes the minimum diameter of a
Geometry
.
The minimum diameter is defined to be the
width of the smallest band that
contains the geometry,
where a band is a strip of the plane defined
by two parallel lines.
This can be thought of as the smallest hole that the geometry can be
moved through, with a single rotation.
The first step in the algorithm is computing the convex hull of the Geometry. If the input Geometry is known to be convex, a hint can be supplied to avoid this computation.
This class can also be used to compute a line segment representing the minimum diameter, the supporting line segment of the minimum diameter, and a minimum rectangle enclosing the input geometry. This rectangle will have width equal to the minimum diameter, and have one side parallel to the supporting segment.
- Version:
- 1.7
- See Also:
-
Field Summary
FieldsModifier and TypeFieldDescriptionprivate Coordinate[]
private final Geometry
private final boolean
private LineSegment
private int
private double
private Coordinate
-
Constructor Summary
ConstructorsConstructorDescriptionMinimumDiameter
(Geometry inputGeom) Compute a minimum diameter for a givenGeometry
.MinimumDiameter
(Geometry inputGeom, boolean isConvex) Compute a minimum diameter for a giverGeometry
, with a hint if the Geometry is convex (e.g. -
Method Summary
Modifier and TypeMethodDescriptionprivate static double
computeC
(double a, double b, Coordinate p) private void
Compute the width information for a ring ofCoordinate
s.private void
private static LineSegment
computeSegmentForLine
(double a, double b, double c) private void
computeWidthConvex
(Geometry convexGeom) private int
findMaxPerpDistance
(Coordinate[] pts, LineSegment seg, int startIndex) Gets aLineString
which is a minimum diameterdouble
Gets the length of the minimum diameter of the input Geometrystatic Geometry
getMinimumDiameter
(Geometry geom) Gets the length of the minimum diameter enclosing a geometryGets the minimum rectangularPolygon
which encloses the input geometry.static Geometry
getMinimumRectangle
(Geometry geom) Gets the minimum rectangle enclosing a geometry.Gets the segment forming the base of the minimum diameterGets theCoordinate
forming one end of the minimum diameterprivate static int
nextIndex
(Coordinate[] pts, int index)
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Field Details
-
inputGeom
-
isConvex
private final boolean isConvex -
convexHullPts
-
minBaseSeg
-
minWidthPt
-
minPtIndex
private int minPtIndex -
minWidth
private double minWidth
-
-
Constructor Details
-
MinimumDiameter
Compute a minimum diameter for a givenGeometry
.- Parameters:
inputGeom
- a Geometry
-
MinimumDiameter
Compute a minimum diameter for a giverGeometry
, with a hint if the Geometry is convex (e.g. a convex Polygon or LinearRing, or a two-point LineString, or a Point).- Parameters:
inputGeom
- a Geometry which is convexisConvex
-true
if the input geometry is convex
-
-
Method Details
-
getMinimumRectangle
Gets the minimum rectangle enclosing a geometry.- Parameters:
geom
- the geometry- Returns:
- the minimum rectangle enclosing the geometry
-
getMinimumDiameter
Gets the length of the minimum diameter enclosing a geometry- Parameters:
geom
- the geometry- Returns:
- the length of the minimum diameter of the geometry
-
getLength
public double getLength()Gets the length of the minimum diameter of the input Geometry- Returns:
- the length of the minimum diameter
-
getWidthCoordinate
Gets theCoordinate
forming one end of the minimum diameter- Returns:
- a coordinate forming one end of the minimum diameter
-
getSupportingSegment
Gets the segment forming the base of the minimum diameter- Returns:
- the segment forming the base of the minimum diameter
-
getDiameter
Gets aLineString
which is a minimum diameter- Returns:
- a
LineString
which is a minimum diameter
-
computeMinimumDiameter
private void computeMinimumDiameter() -
computeWidthConvex
-
computeConvexRingMinDiameter
Compute the width information for a ring ofCoordinate
s. Leaves the width information in the instance variables.- Parameters:
pts
-
-
findMaxPerpDistance
-
nextIndex
-
getMinimumRectangle
Gets the minimum rectangularPolygon
which encloses the input geometry. The rectangle has width equal to the minimum diameter, and a longer length. If the convex hull of the input is degenerate (a line or point) aLineString
orPoint
is returned.The minimum rectangle can be used as an extremely generalized representation for the given geometry.
- Returns:
- the minimum rectangle enclosing the input (or a line or point if degenerate)
-
computeC
-
computeSegmentForLine
-