Class BufferParameters

A value class containing the parameters which specify how a buffer should be constructed.

The parameters allow control over:

Quadrant segments (accuracy of approximation for circular arcs)
End Cap style
Join style
Mitre limit
whether the buffer is single-sided

Inheritance

Object

BufferParameters

Inherited Members

Object.Equals(Object)

Object.Equals(Object, Object)

Object.GetHashCode()

Object.GetType()

Object.MemberwiseClone()

Object.ReferenceEquals(Object, Object)

Object.ToString()

Namespace: NetTopologySuite.Operation.Buffer

Assembly: NetTopologySuite.dll

Syntax

public class BufferParameters

Constructors

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BufferParameters()

Creates a default set of parameters

Declaration

public BufferParameters()

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BufferParameters(Int32)

Creates a set of parameters with the given quadrantSegments value.

Declaration

public BufferParameters(int quadrantSegments)

Parameters

Type	Name	Description
Int32	quadrantSegments	The number of quadrant segments to use

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BufferParameters(Int32, EndCapStyle)

Creates a set of parameters with the given quadrantSegments and endCapStyle values.

Declaration

public BufferParameters(int quadrantSegments, EndCapStyle endCapStyle)

Parameters

Type	Name	Description
Int32	quadrantSegments	the number of quadrant segments to use
EndCapStyle	endCapStyle	the end cap style to use

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BufferParameters(Int32, EndCapStyle, JoinStyle, Double)

Creates a set of parameters with the given parameter values.

Declaration

public BufferParameters(int quadrantSegments, EndCapStyle endCapStyle, JoinStyle joinStyle, double mitreLimit)

Parameters

Type	Name	Description
Int32	quadrantSegments	the number of quadrant segments to use
EndCapStyle	endCapStyle	the end cap style to use
JoinStyle	joinStyle	the join style to use
Double	mitreLimit	the mitre limit to use

Fields

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DefaultJoinStyle

The default number of facets into which to divide a fillet of 90 degrees.
A value of 8 gives less than 2% max error in the buffer distance.

For a max error of < 1%, use QS = 12.

For a max error of < 0.1%, use QS = 18.

Declaration

public const JoinStyle DefaultJoinStyle = JoinStyle.Round

Field Value

Type	Description
JoinStyle

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DefaultMitreLimit

The default mitre limit Allows fairly pointy mitres.

Declaration

public const double DefaultMitreLimit = 5

Field Value

Type	Description
Double

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DefaultQuadrantSegments

The default number of facets into which to divide a fillet of 90 degrees.
A value of 8 gives less than 2% max error in the buffer distance.

For a max error of < 1%, use QS = 12.

For a max error of < 0.1%, use QS = 18.

Declaration

public const int DefaultQuadrantSegments = 8

Field Value

Type	Description
Int32

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DefaultSimplifyFactor

The default simplify factor. Provides an accuracy of about 1%, which matches the accuracy of the DefaultQuadrantSegments parameter.

Declaration

public const double DefaultSimplifyFactor = 0.01

Field Value

Type	Description
Double

Properties

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EndCapStyle

Gets or sets the end cap style of the generated buffer.

Declaration

public EndCapStyle EndCapStyle { get; set; }

Property Value

Type	Description
EndCapStyle

Remarks

The styles supported are Round, Flat, and Square.

The default is Round.

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IsSingleSided

Gets or sets whether the computed buffer should be single-sided. A single-sided buffer is constructed on only one side of each input line.

The side used is determined by the sign of the buffer distance:

a positive distance indicates the left-hand side
a negative distance indicates the right-hand side

The single-sided buffer of point geometries is the same as the regular buffer.

The End Cap Style for single-sided buffers is always ignored, and forced to the equivalent of Flat.

Declaration

public bool IsSingleSided { get; set; }

Property Value

Type	Description
Boolean

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JoinStyle

Gets/Sets the join style for outside (reflex) corners between line segments.

Declaration

public JoinStyle JoinStyle { get; set; }

Property Value

Type	Description
JoinStyle

Remarks

The styles supported are Round, Mitre and Bevel

The default is Round

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MitreLimit

Sets the limit on the mitre ratio used for very sharp corners.

Declaration

public double MitreLimit { get; set; }

Property Value

Type	Description
Double

Remarks

The mitre ratio is the ratio of the distance from the corner to the end of the mitred offset corner. When two line segments meet at a sharp angle, a miter join will extend far beyond the original geometry. (and in the extreme case will be infinitely far.) To prevent unreasonable geometry, the mitre limit allows controlling the maximum length of the join corner. Corners with a ratio which exceed the limit will be beveled.

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QuadrantSegments

Gets or sets the number of line segments in a quarter-circle used to approximate angle fillets in round endcaps and joins. The value should be at least 1.

This determines the error in the approximation to the true buffer curve.
The default value of 8 gives less than 2% error in the buffer distance.

For an error of < 1%, use QS = 12.

For an error of < 0.1%, use QS = 18.

The error is always less than the buffer distance (in other words, the computed buffer curve is always inside the true curve).

Declaration

public int QuadrantSegments { get; set; }

Property Value

Type	Description
Int32

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SimplifyFactor

Factor used to determine the simplify distance tolerance for input simplification. Simplifying can increase the performance of computing buffers. Generally the simplify factor should be greater than 0. Values between 0.01 and .1 produce relatively good accuracy for the generate buffer. Larger values sacrifice accuracy in return for performance.

Declaration

public double SimplifyFactor { get; set; }

Property Value

Type	Description
Double

Methods

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BufferDistanceError(Int32)

Computes the maximum distance error due to a given level of approximation to a true arc.

Declaration

public static double BufferDistanceError(int quadSegs)

Parameters

Type	Name	Description
Int32	quadSegs	The number of segments used to approximate a quarter-circle

Returns

Type	Description
Double	The error of approximation

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Copy()

Creates a copy

Declaration

public BufferParameters Copy()

Returns

Type	Description
BufferParameters