Constructor Detail

• LocationIndexedLine

  public LocationIndexedLine(Geometry linearGeom)

  Constructs an object which allows linear referencing along a given linear Geometry.

  Parameters:

  linearGeom - the linear geometry to reference along

Method Detail

• extractPoint

  public Coordinate extractPoint(LinearLocation index)

  Computes the Coordinate for the point on the line at the given index. If the index is out of range the first or last point on the line will be returned. The Z-ordinate of the computed point will be interpolated from the Z-ordinates of the line segment containing it, if they exist.

  Parameters:

  index - the index of the desired point

  Returns:

  the Coordinate at the given index

• extractPoint

  public Coordinate extractPoint(LinearLocation index,
                                 double offsetDistance)

  Computes the Coordinate for the point on the line at the given index, offset by the given distance. If the index is out of range the first or last point on the line will be returned. The computed point is offset to the left of the line if the offset distance is positive, to the right if negative. The Z-ordinate of the computed point will be interpolated from the Z-ordinates of the line segment containing it, if they exist.

  Parameters:

  index - the index of the desired point

  offsetDistance - the distance the point is offset from the segment (positive is to the left, negative is to the right)

  Returns:

  the Coordinate at the given index

• extractLine

  public Geometry extractLine(LinearLocation startIndex,
                              LinearLocation endIndex)

  Computes the LineString for the interval on the line between the given indices. If the start location is after the end location, the computed linear geometry has reverse orientation to the input line.

  Parameters:

  startIndex - the index of the start of the interval

  endIndex - the index of the end of the interval

  Returns:

  the linear geometry between the indices

• indexOf

  public LinearLocation indexOf(Coordinate pt)

  Computes the index for a given point on the line.

  The supplied point does not necessarily have to lie precisely on the line, but if it is far from the line the accuracy and performance of this function is not guaranteed. Use project(com.vividsolutions.jts.geom.Coordinate) to compute a guaranteed result for points which may be far from the line.

  Parameters:

  pt - a point on the line

  Returns:

  the index of the point

  See Also:

  project(Coordinate)

• indexOfAfter

  public LinearLocation indexOfAfter(Coordinate pt,
                                     LinearLocation minIndex)

  Finds the index for a point on the line which is greater than the given index. If no such index exists, returns minIndex. This method can be used to determine all indexes for a point which occurs more than once on a non-simple line. It can also be used to disambiguate cases where the given point lies slightly off the line and is equidistant from two different points on the line. The supplied point does not necessarily have to lie precisely on the line, but if it is far from the line the accuracy and performance of this function is not guaranteed. Use project(com.vividsolutions.jts.geom.Coordinate) to compute a guaranteed result for points which may be far from the line.

  Parameters:

  pt - a point on the line

  minIndex - the value the returned index must be greater than

  Returns:

  the index of the point greater than the given minimum index

  See Also:

  project(Coordinate)

• indicesOf

  public LinearLocation[] indicesOf(Geometry subLine)

  Computes the indices for a subline of the line. (The subline must conform to the line; that is, all vertices in the subline (except possibly the first and last) must be vertices of the line and occcur in the same order).

  Parameters:

  subLine - a subLine of the line

  Returns:

  a pair of indices for the start and end of the subline.

• project

  public LinearLocation project(Coordinate pt)

  Computes the index for the closest point on the line to the given point. If more than one point has the closest distance the first one along the line is returned. (The point does not necessarily have to lie precisely on the line.)

  Parameters:

  pt - a point on the line

  Returns:

  the index of the point

• getStartIndex

  public LinearLocation getStartIndex()

  Returns the index of the start of the line

  Returns:

  the location index

• getEndIndex

  public LinearLocation getEndIndex()

  Returns the index of the end of the line

  Returns:

  the location index

• isValidIndex

  public boolean isValidIndex(LinearLocation index)

  Tests whether an index is in the valid index range for the line.

  Parameters:

  index - the index to test

  Returns:

  true if the index is in the valid range

• clampIndex

  public LinearLocation clampIndex(LinearLocation index)

  Computes a valid index for this line by clamping the given index to the valid range of index values

  Returns:

  a valid index value