com.vividsolutions.jts.geom
Class LineSegment
java.lang.Object
com.vividsolutions.jts.geom.LineSegment
- Comparable, Serializable
public class LineSegment
extends java.lang.Object
implements Comparable, Serializable
Represents a line segment defined by two
Coordinate
s.
Provides methods to compute various geometric properties
and relationships of line segments.
This class is designed to be easily mutable (to the extent of
having its contained points public).
This supports a common pattern of reusing a single LineSegment
object as a way of computing segment properties on the
segments defined by arrays or lists of
Coordinate
s.
LineSegment
public LineSegment()
angle
public double angle()
- the angle this segment makes with the x-axis (in radians)
closestPoint
public Coordinate closestPoint(Coordinate p)
Computes the closest point on this line segment to another point.
p
- the point to find the closest point to
- a Coordinate which is the closest point on the line segment to the point p
closestPoints
public Coordinate[] closestPoints(LineSegment line)
Computes the closest points on two line segments.
- a pair of Coordinates which are the closest points on the line segments
compareTo
public int compareTo(Object o)
Compares this object with the specified object for order.
Uses the standard lexicographic ordering for the points in the LineSegment.
o
- the LineSegment
with which this LineSegment
is being compared
- a negative integer, zero, or a positive integer as this
LineSegment
is less than, equal to, or greater than the specified LineSegment
distance
public double distance(Coordinate p)
Computes the distance between this line segment and a point.
distance
public double distance(LineSegment ls)
Computes the distance between this line segment and another one.
distancePerpendicular
public double distancePerpendicular(Coordinate p)
Computes the perpendicular distance between the (infinite) line defined
by this line segment and a point.
equals
public boolean equals(Object o)
Returns true
if other
has the same values for
its points.
true
if other
is a LineSegment
with the same values for the x and y ordinates.
equalsTopo
public boolean equalsTopo(LineSegment other)
Returns true
if other
is
topologically equal to this LineSegment (e.g. irrespective
of orientation).
other
- a LineSegment
with which to do the comparison.
true
if other
is a LineSegment
with the same values for the x and y ordinates.
getCoordinate
public Coordinate getCoordinate(int i)
getLength
public double getLength()
Computes the length of the line segment.
- the length of the line segment
intersection
public Coordinate intersection(LineSegment line)
Computes an intersection point between two segments, if there is one.
There may be 0, 1 or many intersection points between two segments.
If there are 0, null is returned. If there is 1 or more, a single one
is returned (chosen at the discretion of the algorithm). If
more information is required about the details of the intersection,
the
RobustLineIntersector
class should be used.
- an intersection point, or
null
if there is none
isHorizontal
public boolean isHorizontal()
Tests whether the segment is horizontal.
true
if the segment is horizontal
isVertical
public boolean isVertical()
Tests whether the segment is vertical.
true
if the segment is vertical
normalize
public void normalize()
Puts the line segment into a normalized form.
This is useful for using line segments in maps and indexes when
topological equality rather than exact equality is desired.
orientationIndex
public int orientationIndex(LineSegment seg)
Determines the orientation of a LineSegment relative to this segment.
The concept of orientation is specified as follows:
Given two line segments A and L,
- A is to the left of a segment L if A lies wholly in the
closed half-plane lying to the left of L
- A is to the right of a segment L if A lies wholly in the
closed half-plane lying to the right of L
- otherwise, A has indeterminate orientation relative to L. This
happens if A is collinear with L or if A crosses the line determined by L.
seg
- the LineSegment to compare
- 1 if
seg
is to the left of this segment
project
public Coordinate project(Coordinate p)
Compute the projection of a point onto the line determined
by this line segment.
Note that the projected point
may lie outside the line segment. If this is the case,
the projection factor will lie outside the range [0.0, 1.0].
project
public LineSegment project(LineSegment seg)
Project a line segment onto this line segment and return the resulting
line segment. The returned line segment will be a subset of
the target line line segment. This subset may be null, if
the segments are oriented in such a way that there is no projection.
Note that the returned line may have zero length (i.e. the same endpoints).
This can happen for instance if the lines are perpendicular to one another.
seg
- the line segment to project
- the projected line segment, or
null
if there is no overlap
projectionFactor
public double projectionFactor(Coordinate p)
Compute the projection factor for the projection of the point p
onto this LineSegment. The projection factor is the constant k
by which the vector for this segment must be multiplied to
equal the vector for the projection of p.
reverse
public void reverse()
Reverses the direction of the line segment.
setCoordinates
public void setCoordinates(LineSegment ls)
toString
public String toString()