com.revolsys.gis.algorithm

Class MatchDistance

java.lang.Object

com.revolsys.gis.algorithm.MatchDistance

public final class MatchDistance
extends Object

Computes various distance functions for determining how far apart are two matched segments. In general these functions use the Hausdorff distance to compute how far apart geometries are, since the normal Euclidean distance is not a useful measure of "far apartness".

Method Summary

Methods

Modifier and Type	Method and Description
static double	maxDistance(LineString a, LineString b) Computes the maximum distance apart between two linestrings.
static double	nearnessFraction(LineString a, LineString b, double tolerance) Computes the fraction of length of LineStrings which is within a given tolerance value, after trimming.
static double	nearnessFraction(LineString a, LineString b, double tolerance, boolean trimLines) Computes the fraction of length of LineStrings which is within a given tolerance value, after trimming.
static double	nearnessFraction(LineString a, LineString b, double maxDistance, double tolerance, boolean trimLines) Computes the fraction of length of matched LineStrings which is nearer than a given tolerance value (optionally after trimming).
static double	trimmedDistance(LineString a, LineString b) Computes how far apart are two linestrings after trimming any unmatched length at the ends.

Methods inherited from class java.lang.Object

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

Method Detail

maxDistance

public static double maxDistance(LineString a,
                 LineString b)

Computes the maximum distance apart between two linestrings. (Note this is NOT the distance between the two furthest points on the linestrings, which is not a useful measure of "farness").

Parameters:

a -

b -

Returns:

nearnessFraction

public static double nearnessFraction(LineString a,
                      LineString b,
                      double tolerance)

Computes the fraction of length of LineStrings which is within a given tolerance value, after trimming. The previously computed maxDistance between the lines can be supplied to allow optimizing the calculation (if maxDistance < tolerance, the nearness fraction = 1.0).

Parameters:

a - a LineString

b - a LineString

fullDistance - the full distance between the lines (previously computed)

tolerance - the distance beyond which to total the length

Returns:

the fraction of length beyond the tolerance

nearnessFraction

public static double nearnessFraction(LineString a,
                      LineString b,
                      double tolerance,
                      boolean trimLines)

Computes the fraction of length of LineStrings which is within a given tolerance value, after trimming.

Parameters:

a - a LineString

b - a LineString

tolerance - the distance beyond which to total the length

trimLines - true if the computation should take the trimmed lines into account

Returns:

the fraction of matched line length beyond the tolerance

nearnessFraction

public static double nearnessFraction(LineString a,
                      LineString b,
                      double maxDistance,
                      double tolerance,
                      boolean trimLines)

Computes the fraction of length of matched LineStrings which is nearer than a given tolerance value (optionally after trimming). The previously computed maxDistance between the lines can be supplied to allow optimizing the calculation (if maxDistance < tolerance, the nearness fraction = 1.0).

Parameters:

a - a LineString

b - a LineString

maxDistance - the maximum distance between the lines (if previously computed)

tolerance - the distance beyond which to total the length

trimLines - true if the computation should take the trimmed lines into account

Returns:

the fraction of matched line length beyond the tolerance

trimmedDistance

public static double trimmedDistance(LineString a,
                     LineString b)

Computes how far apart are two linestrings after trimming any unmatched length at the ends.

Parameters:

a -

b -

Returns:

See Also:

MaximalNearestSubline