org.locationtech.jts.algorithm

Class MinimumDiameter

java.lang.Object

org.locationtech.jts.algorithm.MinimumDiameter

public class MinimumDiameter
extends Object

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
• the minimum-width rectangle of the input geometry. The rectangle has width equal to the minimum diameter, and has one side parallel to the supporting segment. In degenerate cases the rectangle may be a LineString or a Point. (Note that this may not be the enclosing rectangle with minimum area; use MinimumAreaRectangle to compute this.)

Version:

1.7

See Also:

ConvexHull, MinimumAreaRectangle

Constructor Summary

Constructors

Constructor and Description
MinimumDiameter(Geometry inputGeom) Compute a minimum diameter for a given Geometry.
MinimumDiameter(Geometry inputGeom, boolean isConvex) Compute a minimum diameter for a giver Geometry, with a hint if the Geometry is convex (e.g.

Method Summary

Modifier and Type	Method and Description
LineString	getDiameter() Gets a LineString which is a minimum diameter
double	getLength() Gets the length of the minimum diameter of the input Geometry
static Geometry	getMinimumDiameter(Geometry geom) Gets the length of the minimum diameter enclosing a geometry
Geometry	getMinimumRectangle() Gets the rectangular Polygon which encloses the input geometry and is based on the minimum diameter supporting segment.
static Geometry	getMinimumRectangle(Geometry geom) Gets the minimum-width rectangular Polygon which encloses the input geometry and is based along the supporting segment.
LineString	getSupportingSegment() Gets the segment forming the base of the minimum diameter
Coordinate	getWidthCoordinate() Gets the Coordinate forming one end of the minimum diameter

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

MinimumDiameter

public MinimumDiameter(Geometry inputGeom)

Compute a minimum diameter for a given Geometry.

Parameters:

inputGeom - a Geometry

MinimumDiameter

public MinimumDiameter(Geometry inputGeom,
                       boolean isConvex)

Compute a minimum diameter for a giver Geometry, 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 convex

isConvex - true if the input geometry is convex

Method Detail

getMinimumRectangle

public static Geometry getMinimumRectangle(Geometry geom)

Gets the minimum-width rectangular Polygon which encloses the input geometry and is based along the supporting segment. 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) a LineString or Point is returned.

This is not necessarily the rectangle with minimum area. Use MinimumAreaRectangle to compute this.

Parameters:

geom - the geometry

Returns:

the minimum-width rectangle enclosing the geometry

See Also:

MinimumAreaRectangle

getMinimumDiameter

public static Geometry getMinimumDiameter(Geometry geom)

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

public Coordinate getWidthCoordinate()

Gets the Coordinate forming one end of the minimum diameter

Returns:

a coordinate forming one end of the minimum diameter

getSupportingSegment

public LineString getSupportingSegment()

Gets the segment forming the base of the minimum diameter

Returns:

the segment forming the base of the minimum diameter

getDiameter

public LineString getDiameter()

Gets a LineString which is a minimum diameter

Returns:

a LineString which is a minimum diameter

getMinimumRectangle

public Geometry getMinimumRectangle()

Gets the rectangular Polygon which encloses the input geometry and is based on the minimum diameter supporting segment. 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) a LineString or Point is returned.

This is not necessarily the enclosing rectangle with minimum area.

Returns:

a rectangle enclosing the input (or a line or point if degenerate)

See Also:

MinimumAreaRectangle