com.vividsolutions.jts.linearref

Class LinearLocation

java.lang.Object

com.vividsolutions.jts.linearref.LinearLocation

All Implemented Interfaces:

Comparable

public class LinearLocation
extends Object
implements Comparable

Represents a location along a LineString or MultiLineString. The referenced geometry is not maintained within this location, but must be provided for operations which require it. Various methods are provided to manipulate the location value and query the geometry it references.

Constructor Summary

Constructors

Constructor and Description
LinearLocation() Creates a location referring to the start of a linear geometry
LinearLocation(int segmentIndex, double segmentFraction)
LinearLocation(int componentIndex, int segmentIndex, double segmentFraction)
LinearLocation(LinearLocation loc) Creates a new location equal to a given one.

Method Summary

Methods

Modifier and Type	Method and Description
void	clamp(Geometry linear) Ensures the indexes are valid for a given linear Geometry.
Object	clone() Copies this location
int	compareLocationValues(int componentIndex1, int segmentIndex1, double segmentFraction1) Compares this object with the specified index values for order.
static int	compareLocationValues(int componentIndex0, int segmentIndex0, double segmentFraction0, int componentIndex1, int segmentIndex1, double segmentFraction1) Compares two sets of location values for order.
int	compareTo(Object o) Compares this object with the specified object for order.
int	getComponentIndex() Gets the component index for this location.
Coordinate	getCoordinate(Geometry linearGeom) Gets the Coordinate along the given linear Geometry which is referenced by this location.
static LinearLocation	getEndLocation(Geometry linear) Gets a location which refers to the end of a linear Geometry.
LineSegment	getSegment(Geometry linearGeom) Gets a LineSegment representing the segment of the given linear Geometry which contains this location.
double	getSegmentFraction() Gets the segment fraction for this location
int	getSegmentIndex() Gets the segment index for this location
double	getSegmentLength(Geometry linearGeom) Gets the length of the segment in the given Geometry containing this location.
boolean	isEndpoint(Geometry linearGeom) Tests whether this location is an endpoint of the linear component it refers to.
boolean	isOnSameSegment(LinearLocation loc) Tests whether two locations are on the same segment in the parent Geometry.
boolean	isValid(Geometry linearGeom) Tests whether this location refers to a valid location on the given linear Geometry.
boolean	isVertex() Tests whether this location refers to a vertex
static Coordinate	pointAlongSegmentByFraction(Coordinate p0, Coordinate p1, double frac) Computes the Coordinate of a point a given fraction along the line segment (p0, p1).
void	setToEnd(Geometry linear) Sets the value of this location to refer to the end of a linear geometry.
void	snapToVertex(Geometry linearGeom, double minDistance) Snaps the value of this location to the nearest vertex on the given linear Geometry, if the vertex is closer than minDistance.
LinearLocation	toLowest(Geometry linearGeom) Converts a linear location to the lowest equivalent location index.
String	toString()

Methods inherited from class java.lang.Object

equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

LinearLocation

public LinearLocation()

Creates a location referring to the start of a linear geometry

LinearLocation

public LinearLocation(int segmentIndex,
              double segmentFraction)

LinearLocation

public LinearLocation(int componentIndex,
              int segmentIndex,
              double segmentFraction)

LinearLocation

public LinearLocation(LinearLocation loc)

Creates a new location equal to a given one.

Parameters:

loc - a LinearLocation

Method Detail

getEndLocation

public static LinearLocation getEndLocation(Geometry linear)

Gets a location which refers to the end of a linear Geometry.

Parameters:

linear - the linear geometry

Returns:

a new LinearLocation

pointAlongSegmentByFraction

public static Coordinate pointAlongSegmentByFraction(Coordinate p0,
                                     Coordinate p1,
                                     double frac)

Computes the Coordinate of a point a given fraction along the line segment (p0, p1). If the fraction is greater than 1.0 the last point of the segment is returned. If the fraction is less than or equal to 0.0 the first point of the segment is returned. The Z ordinate is interpolated from the Z-ordinates of the given points, if they are specified.

Parameters:

p0 - the first point of the line segment

p1 - the last point of the line segment

frac - the length to the desired point

Returns:

the Coordinate of the desired point

clamp

public void clamp(Geometry linear)

Ensures the indexes are valid for a given linear Geometry.

Parameters:

linear - a linear geometry

snapToVertex

public void snapToVertex(Geometry linearGeom,
                double minDistance)

Snaps the value of this location to the nearest vertex on the given linear Geometry, if the vertex is closer than minDistance.

Parameters:

linearGeom - a linear geometry

minDistance - the minimum allowable distance to a vertex

getSegmentLength

public double getSegmentLength(Geometry linearGeom)

Gets the length of the segment in the given Geometry containing this location.

Parameters:

linearGeom - a linear geometry

Returns:

the length of the segment

setToEnd

public void setToEnd(Geometry linear)

Sets the value of this location to refer to the end of a linear geometry.

Parameters:

linear - the linear geometry to use to set the end

getComponentIndex

public int getComponentIndex()

Gets the component index for this location.

Returns:

the component index

getSegmentIndex

public int getSegmentIndex()

Gets the segment index for this location

Returns:

the segment index

getSegmentFraction

public double getSegmentFraction()

Gets the segment fraction for this location

Returns:

the segment fraction

isVertex

public boolean isVertex()

Tests whether this location refers to a vertex

Returns:

true if the location is a vertex

getCoordinate

public Coordinate getCoordinate(Geometry linearGeom)

Gets the Coordinate along the given linear Geometry which is referenced by this location.

Parameters:

linearGeom - the linear geometry referenced by this location

Returns:

the Coordinate at the location

getSegment

public LineSegment getSegment(Geometry linearGeom)

Gets a LineSegment representing the segment of the given linear Geometry which contains this location.

Parameters:

linearGeom - a linear geometry

Returns:

the LineSegment containing the location

isValid

public boolean isValid(Geometry linearGeom)

Tests whether this location refers to a valid location on the given linear Geometry.

Parameters:

linearGeom - a linear geometry

Returns:

true if this location is valid

compareTo

public int compareTo(Object o)

Compares this object with the specified object for order.

Specified by:

compareTo in interface Comparable

Parameters:

o - the LineStringLocation with which this Coordinate is being compared

Returns:

a negative integer, zero, or a positive integer as this LineStringLocation is less than, equal to, or greater than the specified LineStringLocation

compareLocationValues

public int compareLocationValues(int componentIndex1,
                        int segmentIndex1,
                        double segmentFraction1)

Compares this object with the specified index values for order.

Parameters:

componentIndex1 - a component index

segmentIndex1 - a segment index

segmentFraction1 - a segment fraction

Returns:

a negative integer, zero, or a positive integer as this LineStringLocation is less than, equal to, or greater than the specified locationValues

compareLocationValues

public static int compareLocationValues(int componentIndex0,
                        int segmentIndex0,
                        double segmentFraction0,
                        int componentIndex1,
                        int segmentIndex1,
                        double segmentFraction1)

Compares two sets of location values for order.

Parameters:

componentIndex0 - a component index

segmentIndex0 - a segment index

segmentFraction0 - a segment fraction

componentIndex1 - another component index

segmentIndex1 - another segment index

segmentFraction1 - another segment fraction

Returns:

a negative integer, zero, or a positive integer as the first set of location values is less than, equal to, or greater than the second set of locationValues

isOnSameSegment

public boolean isOnSameSegment(LinearLocation loc)

Tests whether two locations are on the same segment in the parent Geometry.

Parameters:

loc - a location on the same geometry

Returns:

true if the locations are on the same segment of the parent geometry

isEndpoint

public boolean isEndpoint(Geometry linearGeom)

Tests whether this location is an endpoint of the linear component it refers to.

Parameters:

linearGeom - the linear geometry referenced by this location

Returns:

true if the location is a component endpoint

toLowest

public LinearLocation toLowest(Geometry linearGeom)

Converts a linear location to the lowest equivalent location index. The lowest index has the lowest possible component and segment indices.

Specifically:

• if the location point is an endpoint, a location value is returned as (nseg-1, 1.0)
• if the location point is ambiguous (i.e. an endpoint and a startpoint), the lowest endpoint location is returned

If the location index is already the lowest possible value, the original location is returned.

Parameters:

linearGeom - the linear geometry referenced by this location

Returns:

the lowest equivalent location

clone

public Object clone()

Copies this location

Overrides:

clone in class Object

Returns:

a copy of this location

toString

public String toString()

Overrides:

toString in class Object