org.tinfour.standard

Class IntegrityCheck

java.lang.Object

org.tinfour.standard.IntegrityCheck

All Implemented Interfaces:

IIntegrityCheck

public class IntegrityCheck
extends Object
implements IIntegrityCheck

A tool for checking the correctness of a tin, in particular the relationship between adjacent triangles. The name of this class is inspired by the idea of a "relational integrity check" in relational database management systems. And that choice of nomenclature should give some sense of its intended role.

Method Summary

Modifier and Type	Method and Description
int	getConstrainedViolationCount() Gets the number of constrained edges that would violate the Delaunay criterion
double	getConstrainedViolationMaximum() Get the maximum calculated in-circle score for constrained edges that violate the Delaunay criterion
double	getContrainedViolationAverage() Get the average calculated in-circle score for constrained edges that violate the Delaunay criterion
String	getMessage() Gets descriptive information about the cause of a test failure.
boolean	inspect() Performs an inspection of the TIN checking for conditions that violate the construction rules.
boolean	inspectLinks() Inspects the references that connect various edges in the TIN.
boolean	inspectPerimeterLinks() Inspects the edges related to the perimeter (convex hull) of the TIN.
boolean	inspectTriangleGeometry() Inspects the triangles forming the TIN.
boolean	isCheckOkay() Determines whether the most recent integrity check completed okay.
void	printSummary(PrintStream ps) Prints a summary of data collected during inspection of a TIN.
boolean	testGetVerticesAgainstInputList(List<Vertex> inputList) Compares the list of vertices from the getVertices() method to the original list of input vertices and determines whether they are consistent.

Methods inherited from class java.lang.Object

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

Method Detail

inspect

public boolean inspect()

Performs an inspection of the TIN checking for conditions that violate the construction rules.

The Rules

• Ensure that every edge links to two valid triangular circuits (one on each side).
• Ensure that the set of ghost triangles forms a closed loop around the convex hull (perimeter) of the TIN
• Ensure that all ghost triangles are included in the perimeter loop
• Ensure that no triangles are degenerate (negative or zero area)
• Ensure that all triangle pairs are Delaunay or close-to-Delaunay optimal

Specified by:

inspect in interface IIntegrityCheck

Returns:

if the TIN passes inspection, true; otherwise, false.

inspectLinks

public boolean inspectLinks()

Inspects the references that connect various edges in the TIN. This test passes if the following conditions are met:

• Proper triangular circuits are formed
• Forward and reverse references are mutually consistent
• All allocated edges are fully populated with references

If an inspection fails, information about the cause may be obtained through a call to getMessage().

Returns:

true if all inspection criteria are met; otherwise false.

inspectPerimeterLinks

public boolean inspectPerimeterLinks()

Inspects the edges related to the perimeter (convex hull) of the TIN. This test passes if the following conditions are met:

• The dual of all perimeter edges is the base of a ghost triangle.
• Forward and reverse references are mutually consistent
• The number of perimeter edges equals the number of ghost edges
• The area of the perimeter as obtained using the getPermiter() method is greater than zero (e.g. has a counterclockwise orientation).

If an inspection fails, information about the cause may be obtained through a call to getMessage().

Returns:

true if all inspection criteria are met; otherwise false.

inspectTriangleGeometry

public boolean inspectTriangleGeometry()

Inspects the triangles forming the TIN. This test passes if the following conditions are met:

• All triangles are non-degenerate (have an area greater than zero).
• The two triangles associated with each edge do not violate the Delaunay criterion within a degree of tolerance specified by the delaunayThreshold for the TIN.

This inspection has a limitation in that the method of checking the Delaunay criterion uses the same finite-precision logic that the TIN building routine uses. So, at best, a passing result verifies that the logic is self-consistent, but does not guarantee that the triangular mesh is truly Delaunay optimal.

If an inspection fails, information about the cause may be obtained through a call to getMessage().

Returns:

true if all inspection criteria are met; otherwise false.

getMessage

public String getMessage()

Gets descriptive information about the cause of a test failure.

Specified by:

getMessage in interface IIntegrityCheck

Returns:

if a failure occurred, descriptive information; otherwise a string indicating that No Error Detected.

isCheckOkay

public boolean isCheckOkay()

Determines whether the most recent integrity check completed okay.

Returns:

true if the integrity check was okay.

printSummary

public void printSummary(PrintStream ps)

Description copied from interface: IIntegrityCheck

Prints a summary of data collected during inspection of a TIN.

Specified by:

printSummary in interface IIntegrityCheck

Parameters:

ps - a print stream to receive the output.

testGetVerticesAgainstInputList

public boolean testGetVerticesAgainstInputList(List<Vertex> inputList)

Description copied from interface: IIntegrityCheck

Compares the list of vertices from the getVertices() method to the original list of input vertices and determines whether they are consistent. The getVertices method must return one, and only one, instance of each vertex in the input list.

This method does not account for cases where constraints have been added to the TIN. If constraints have been added, it will return a value of false.

Important: The test assumes that each vertex in the input set is unique. If a vertex occurs more than once, the test will fail.

Specified by:

testGetVerticesAgainstInputList in interface IIntegrityCheck

Parameters:

inputList - the list of vertices input into the TIN.

Returns:

true if the test passes; otherwise false

getConstrainedViolationCount

public int getConstrainedViolationCount()

Description copied from interface: IIntegrityCheck

Gets the number of constrained edges that would violate the Delaunay criterion

Specified by:

getConstrainedViolationCount in interface IIntegrityCheck

Returns:

a positive integer.

getConstrainedViolationMaximum

public double getConstrainedViolationMaximum()

Description copied from interface: IIntegrityCheck

Get the maximum calculated in-circle score for constrained edges that violate the Delaunay criterion

Specified by:

getConstrainedViolationMaximum in interface IIntegrityCheck

Returns:

a positive number, or zero if no violations occurred.

getContrainedViolationAverage

public double getContrainedViolationAverage()

Description copied from interface: IIntegrityCheck

Get the average calculated in-circle score for constrained edges that violate the Delaunay criterion

Specified by:

getContrainedViolationAverage in interface IIntegrityCheck

Returns:

a positive number, or zero if no violations occurred.