Class CoverageValidator

Validates a polygonal coverage, and returns the locations of invalid polygon boundary segments if found.

A polygonal coverage is a set of polygons which may be edge-adjacent but do not overlap. Coverage algorithms(such as { @link CoverageUnion} or simplification) generally require the input coverage to be valid to produce correct results. A polygonal coverage is valid if:

1. The interiors of all polygons do not intersect(are disjoint). This is the case if no polygon has a boundary which intersects the interior of another polygon, and no two polygons are identical.
2. If the boundaries of polygons intersect, the vertices and line segments of the intersection match exactly.

A valid coverage may contain holes(regions of no coverage). Sometimes it is desired to detect whether coverages contain narrow gaps between polygons (which can be a result of digitizing error or misaligned data). This class can detect narrow gaps, by specifying a maximum gap width using {@link #setGapWidth(double)}. Note that this also identifies narrow gaps separating disjoint coverage regions, and narrow gores. In some situations it may also produce false positives (linework identified as part of a gap which is actually wider). See CoverageGapFinder for an alternate way to detect gaps which may be more accurate.

Inheritance

object

CoverageValidator

Inherited Members

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.MemberwiseClone()

object.ReferenceEquals(object, object)

object.ToString()

Namespace: NetTopologySuite.Coverage

Assembly: NetTopologySuite.dll

Syntax

public class CoverageValidator

Constructors

CoverageValidator(Geometry[])

Creates a new coverage validator

Declaration

public CoverageValidator(Geometry[] coverage)

Parameters

Type	Name	Description
Geometry[]	coverage	An array of polygons representing a polygonal coverage

Properties

GapWidth

Gets or sets a value indicating the maximum gap, if narrow gaps are to be detected.

Declaration

public double GapWidth { get; set; }

Property Value

Type	Description
double

Methods

HasInvalidResult(Geometry[])

Tests if some element of an array of geometries is a coverage invalidity indicator.

Declaration

public static bool HasInvalidResult(Geometry[] validateResult)

Parameters

Type	Name	Description
Geometry[]	validateResult	An array produced by a polygonal coverage validation

Returns

Type	Description
bool	true if the result has at least one invalid indicator

IsValid(Geometry[])

Tests whether a polygonal coverage is valid.

Declaration

public static bool IsValid(Geometry[] coverage)

Parameters

Type	Name	Description
Geometry[]	coverage	An array of polygons forming a coverage

Returns

Type	Description
bool	true if the coverage is valid

Remarks

Named isValid in JTS

Validate()

Validates the polygonal coverage. The result is an array of the same size as the input coverage. Each array entry is either null, or if the polygon does not form a valid coverage, a linear geometry containing the boundary segments which intersect polygon interiors, which are mismatched, or form gaps (if checked).

Declaration

public Geometry[] Validate()

Returns

Type	Description
Geometry[]	An array of nulls or linear geometries

Validate(Geometry[])

Validates that a set of polygons forms a valid polygonal coverage, and returns linear geometries indicating the locations of invalidities, if any.

Declaration

public static Geometry[] Validate(Geometry[] coverage)

Parameters

Type	Name	Description
Geometry[]	coverage	An array of polygons forming a coverage

Returns

Type	Description
Geometry[]	An array of linear geometries indicating coverage errors, or nulls

Validate(Geometry[], double)

Validates that a set of polygons forms a valid polygonal coverage and contains no gaps narrower than a specified width. The result is an array of linear geometries indicating the locations of invalidities, or null if the polygon is coverage-valid.

Declaration

public static Geometry[] Validate(Geometry[] coverage, double gapWidth)

Parameters

Type	Name	Description
Geometry[]	coverage	An array of polygons forming a coverage
double	gapWidth	The maximum width of invalid gaps

Returns

Type	Description
Geometry[]	An array of linear geometries indicating coverage errors, or nulls