org.locationtech.jts:jts-core 1.17.0
org.locationtech.jts.algorithm.construct

## Class MaximumInscribedCircle

• java.lang.Object
• org.locationtech.jts.algorithm.construct.MaximumInscribedCircle

• ```public class MaximumInscribedCircle
extends Object```
Constructs the Maximum Inscribed Circle for a polygonal `Geometry`, up to a specified tolerance. The Maximum Inscribed Circle is determined by a point in the interior of the area which has the farthest distance from the area boundary, along with a boundary point at that distance.

In the context of geography the center of the Maximum Inscribed Circle is known as the Pole of Inaccessibility. A cartographic use case is to determine a suitable point to place a map label within a polygon.

The radius length of the Maximum Inscribed Circle is a measure of how "narrow" a polygon is. It is the distance at which the negative buffer becomes empty.

The class supports polygons with holes and multipolygons.

The implementation uses a successive-approximation technique over a grid of square cells covering the area geometry. The grid is refined using a branch-and-bound algorithm. Point containment and distance are computed in a performant way by using spatial indexes.

### Future Enhancements

• Support a polygonal constraint on placement of center
Author:
Martin Davis
• ### Constructor Summary

Constructors
Constructor and Description
```MaximumInscribedCircle(Geometry polygonal, double tolerance)```
Creates a new instance of a Maximum Inscribed Circle computation.
• ### Method Summary

All Methods
Modifier and Type Method and Description
`Point` `getCenter()`
Gets the center point of the maximum inscribed circle (up to the tolerance distance).
`static Point` ```getCenter(Geometry polygonal, double tolerance)```
Computes the center point of the Maximum Inscribed Circle of a polygonal geometry, up to a given tolerance distance.
`LineString` `getRadiusLine()`
Gets a line representing a radius of the Largest Empty Circle.
`static LineString` ```getRadiusLine(Geometry polygonal, double tolerance)```
Computes a radius line of the Maximum Inscribed Circle of a polygonal geometry, up to a given tolerance distance.
`Point` `getRadiusPoint()`
Gets a point defining the radius of the Maximum Inscribed Circle.
• ### Methods inherited from class java.lang.Object

`equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`
• ### Constructor Detail

• #### MaximumInscribedCircle

```public MaximumInscribedCircle(Geometry polygonal,
double tolerance)```
Creates a new instance of a Maximum Inscribed Circle computation.
Parameters:
`polygonal` - an areal geometry
`tolerance` - the distance tolerance for computing the centre point
• ### Method Detail

• #### getCenter

```public static Point getCenter(Geometry polygonal,
double tolerance)```
Computes the center point of the Maximum Inscribed Circle of a polygonal geometry, up to a given tolerance distance.
Parameters:
`polygonal` - a polygonal geometry
`tolerance` - the distance tolerance for computing the center point
Returns:
the center point of the maximum inscribed circle

```public static LineString getRadiusLine(Geometry polygonal,
double tolerance)```
Computes a radius line of the Maximum Inscribed Circle of a polygonal geometry, up to a given tolerance distance.
Parameters:
`polygonal` - a polygonal geometry
`tolerance` - the distance tolerance for computing the center point
Returns:
a line from the center to a point on the circle
• #### getCenter

`public Point getCenter()`
Gets the center point of the maximum inscribed circle (up to the tolerance distance).
Returns:
the center point of the maximum inscribed circle

`public Point getRadiusPoint()`
Gets a point defining the radius of the Maximum Inscribed Circle. This is a point on the boundary which is nearest to the computed center of the Maximum Inscribed Circle. The line segment from the center to this point is a radius of the constructed circle, and this point lies on the boundary of the circle.
Returns:
a point defining the radius of the Maximum Inscribed Circle
`public LineString getRadiusLine()`