IrregularTransObj class

The IrregularTransObj class manages forward and backward transformations in an irregular rectangular coordinate space.

Synopsis

Header file:		ncarg/hlu/IrregularTransObj.h
Class name:		irregularTransObjClass
Class pointer:		<Not referenceable>
Fortran class function:	<Not referenceable>
Superclass:		TransObj
Composite classes:	<None>

Class-defined types

Type name:		NhlTAxisType
Definition:
typedef enum _NhlAxisType {
	NhlIRREGULARAXIS	= 0,	/* "IrregularAxis"	*/
	NhlLINEARAXIS		= 1,	/* "LinearAxis"		*/
	NhlLOGAXIS		= 2	/* "LogAxis"		*/
} NhlAxisType;

Resources

Local resources

+---------------------------------------------------------------+
|			IrregularTransObj Resource Set		|
|---------------------------------------------------------------|
| NAME				TYPE			ACCESS	|
|	CLASS				DEFAULT			|
|===============================================================|
| trXAxisType			NhlTAxisType		RCSG	|
|	TrXAxisType			"LinearAxis"		|
|---------------------------------------------------------------|
| trXCoordPoints		NhlTFloatGenArray	RCSG	|
|	TrXCoordPoints			NULL			|
|---------------------------------------------------------------|
| trXInterPoints		NhlTFloatGenArray	RCSG	|
|	TrXInterPoints			NULL			|
|---------------------------------------------------------------|
| trXMaxF			NhlTFloat		RCSG	|
|	TrXMaxF				0.0			|
|---------------------------------------------------------------|
| trXMinF			NhlTFloat		RCSG	|
|	TrXMinF				0.0			|
|---------------------------------------------------------------|
| trXReverse			NhlTBoolean		RCSG	|
|	TrXReverse			False			|
|---------------------------------------------------------------|
| trXTensionF			NhlTFloat		RCSG	|
|	TrXTensionF			2.0			|
|---------------------------------------------------------------|
| trXSamples			NhlTInteger		RCSG	|
|	TrXSamples			9			|
|---------------------------------------------------------------|
| trYAxisType			NhlTAxisType		RCSG	|
|	TrYAxisType			"LinearAxis"		|
|---------------------------------------------------------------|
| trYCoordPoints		NhlTFloatGenArray	RCSG	|
|	TrYCoordPoints			NULL			|
|---------------------------------------------------------------|
| trYInterPoints		NhlTFloatGenArray	RCSG	|
|	TrYInterPoints			NULL			|
|---------------------------------------------------------------|
| trYMaxF			NhlTFloat		RCSG	|
|	TrYMaxF				0.0			|
|---------------------------------------------------------------|
| trYMinF			NhlTFloat		RCSG	|
|	TrYMinF				0.0			|
|---------------------------------------------------------------|
| trYReverse			NhlTBoolean		RCSG	|
|	TrYReverse			False			|
|---------------------------------------------------------------|
| trYTensionF			NhlTFloat		RCSG	|
|	TrYTensionF			2.0			|
|---------------------------------------------------------------|
| trYSamples			NhlTInteger		RCSG	|
|	TrYSamples			9			|
+---------------------------------------------------------------+

Composite resources

The IrregularTransObj class has no composite class objects.

Superclass resources

You can set all resources defined by the superclasses of the IrregularTransObj object class, including:

TransObj resources

Description

The IrregularTransObj provides transformations into a rectangular irregularly gridded coordinate space for plot objects belonging to the Transform class. It contains resources for specifying the mapping from the linear space into the irregularly gridded space. Within the defined coordinate bounds you can specify the coordinate extent along each of its axes. You can specify the direction of increasing coordinate values. You can also choose to create a transformation that is irregular along one axis and logarithmic or linear along the other. (Actually, there is nothing to prevent you from making both axes linear or logarithmic, but you would pay a performance penalty compared with simply using the LogLinTransObj in this case.)

Currently some plot objects, such as the XyPlot object, have their own resources for setting the IrregularTransObj resources. For these objects the IrregularTransObj resources are considered private. The ContourPlot object allows access only to the boundary setting resources. The IrregularPlot object currently allows you to access all resources of the IrregularTransObj.

The ContourPlot object requires that the extent of an irregular coordinate system be coincident with or a subset of the data extent as defined by the array resources sfXArray and sfYArray belonging to the ScalarField object. However, by overlaying a ContourPlot object on an IrregularPlot object, you can create a ContourPlot plot that is arbitrarily positioned in relation to the plot as a whole.

Support functions

The IrregularTransObj object does not define any support functions, but inherits all the support functions available to its superclass.

Status

2: Irregular transformations may fail if the values of trXCoordPoints or trYCoordPoints represent samples of a transformation that is "too" irregular. What constitutes a "too" irregular transformation requires further investigation.

4:Large values of trXTensionF or trYTensionF (> ~10.0) may cause instability in the irregular transformation.

Copyright

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$Revision: 1.13 $ $Date: 1995/07/26 23:29:48 $