ISpatialReferenceTolerance Interface

Provides access to members that specify the spatial and M tolerances of a spatial reference.

Product Availability

When To Use

Use the ISpatialReferenceTolerance interface to define default and user-specified XYTolerance and ZTolerance parameters utilized by the topology engine when performing geometric and relational operations on geometries associated with this spatial reference.  This interface also provides access to define the MTolerance used by the geometric and relational operations associated with this spatial reference.

Members

	Name	Description
	IsMToleranceEqual	Returns true if the measure tolerances of the two spatial references are the same.
	IsXYToleranceEqual	Returns true if the XY tolerances of the two spatial references are the same.
	IsZToleranceEqual	Returns true if the Z tolerances of the two spatial references are the same.
	MTolerance	The tolerance used to determine equality of M values.
	MToleranceValid	Returns true if the M tolerance is well defined (not NaN) and >= the minimum M tolerance.
	SetDefaultMTolerance	Sets the default tolerance used to determine equality of M values (2.0 * m resolution).
	SetDefaultXYTolerance	Sets the default cluster tolerance used to control point coalescing in the X and Y dimensions (the equivalent of 1 mm in the current spatial reference units).
	SetDefaultZTolerance	Sets the default value for the Z cluster tolerance used to control point coalescing strictly along the Z axis (the equivalent of 1 mm in the current vertical coordinate system units).
	SetMinimumMTolerance	Sets the minimum tolerance (i.e., pre 9.2) used to determine equality of M values (2.0 * m resolution).
	SetMinimumXYTolerance	Sets the xy cluster tolerance to be 2.0 * resolution. Use this value for compatibility with pre-9.2 topological and relational operators.
	SetMinimumZTolerance	Sets the minimum value for the Z cluster tolerance (i.e., pre 9.2) used to control point coalescing strictly along the Z axis (the equivalent of 1 mm in the current vertical coordinate system units).
	XYTolerance	The xy tolerance used to control point coalescing in the X and Y dimensions.
	XYToleranceValid	Returns esriSRToleranceOK if the XY tolerance is well defined (not NaN) and >= the minimum XY tolerance.
	ZTolerance	The tolerance used to control point coalescing strictly along the Z axis.
	ZToleranceValid	Returns true if the Z tolerance is well defined (not NaN) and >= the minimum Z tolerance.

Classes that implement ISpatialReferenceTolerance

Remarks

The tolerance values for a spatial reference remain NaN until they are either set explicitly using one of the methods or properties available on this interface or as a result of calling a method which defines the resolution of the spatial reference, including ISpatialReference::SetDomain, ISpatialReference::SetZDomain, ISpatialReference::SetMDomain, ISpatialReference::SetFalseOriginAndUnits, ISpatialReference::SetZFalseOriginAndUnits and ISpatialReference::SetMFalseOriginAndUnits.  These methods will set the corresponding tolerance to its minimum value if it is currently undefined (NaN). 

It is generally good practice to check the validity of the tolerance after setting it using any of the available methods.

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