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ContourPlot class

The ContourPlot class draws line or filled contours with labels and annotations.

Synopsis

Header file:		ncarg/hlu/ContourPlot.h
Class name:		contourPlotClass
Class pointer:		NhlcontourPlotClass
Fortran class function:	NHLFCONTOURPLOTCLASS
Superclass:		DataComm
Composite classes:	LogLinTransformation, 
			IrregularTransformation,
			CurvilinearTransformation, 
			SphericalTransformation,
			TriangularMeshTransformation,
			PlotManager

Data specific class
Class name:		contourPlotDataDepClass
Class pointer:		NhlcontourPlotDataDepClass
Fortran class function:	NHLFCONTOURPLOTDATADEPCLASS
Superclass:		DataSpec

Class-defined types


Type name:		NhlTcnLevelUseMode
Definition:
typedef enum _NhlcnLevelUseMode {
	NhlNOLINE		= 0,	/* "NoLine"	  	*/
	NhlLINEONLY		= 1,	/* "LineOnly"	  	*/
	NhlLABELONLY		= 2,	/* "LabelOnly"	  	*/
	NhlLINEANDLABEL		= 3	/* "LineAndLabel"	*/
} NhlcnLevelUseMode;

Type name:		NhlTcnLevelUseModeGenArray
Definition:		An array of NhlTcnLevelUseMode elements.


Type name:		NhlTcnLineLabelPlacementMode
Definition:
typedef enum _NhlcnLineLabelSpacingMode {
	NhlCONSTANT		= 0,	/* "Constant"		*/
	NhlRANDOMIZED		= 1,	/* "Randomized"		*/
	NhlCOMPUTED		= 2	/* "Computed"		*/
} NhlcnLineLabelSpacingMode;

Type name:		NhlTcnHighLowLabelOverlapMode
Definition:
typedef enum _NhlcnHighLowLabelOverlapMode {
	NhlIGNOREOVERLAP	= 0,1	/* "IgnoreOverlap"	*/
	NhlOMITOVERHL		= 2,3	/* "OmitOverHL" 	*/
	NhlOMITOVERVP		= 4,5	/* "OmitOverVP"		*/
	NhlOMITOVERVPANDHL	= 6,7	/* "OmitOverVPAndHL"	*/
	NhlADJUSTVP		= 8,9	/* "AdjustVP"		*/
	NhlADJUSTVPOMITOVERHL	= 10,11	/* "AdjustVPOmitOverHL"	*/
} NhlcnHighLowLabelOverlapMode;

Type name:		NhlTcnFillMode
Definition:
typedef enum _NhlcnFillMode {
	NhlAREAFILL		= 0,	/* "AreaFill"		*/
	NhlRASTERFILL		= 1,	/* "RasterFill"		*/
	NhlCELLFILL		= 2	/* "CellFill"		*/
} NhlcnFillMode;

Resources

Local resources

+---------------------------------------------------------------+
|		ContourPlot Resource Set			|
|---------------------------------------------------------------|
| NAME				TYPE			ACCESS	|
|	CLASS				DEFAULT			|
|===============================================================|
| cnScalarFieldData             NhlTInteger             RCSG    |
|       CnScalarFieldData               <None>                  |
|---------------------------------------------------------------|
| cnLevelSelectionMode          NhlTLevelSelectionMode  RCSG    |
|       LevelSelectionMode              "AutomaticLevels"       |
|---------------------------------------------------------------|
| cnLevelCount                  NhlTInteger                G    |
|       CnLevelCount                    <dynamic>               |
|---------------------------------------------------------------|
| cnMaxLevelCount               NhlTInteger             RCSG    |
|       MaxLevelCount                   16                      |
|---------------------------------------------------------------|
| cnLevelSpacingF               NhlTFloat               RCSG    |
|       LevelSpacingF                   5.0                     |
|---------------------------------------------------------------|
| cnMinLevelValF                NhlTFloat               RCSG    |
|       MinLevelValF                    <dynamic>               |
|---------------------------------------------------------------|
| cnMaxLevelValF                NhlTFloat               RCSG    |
|       MaxLevelValF                    <dynamic>               |
|---------------------------------------------------------------|
| cnLevels                      NhlTFloatGenArray       RCSG    |
|       Levels                          <dynamic>               |
|---------------------------------------------------------------|
| cnMonoLevelFlag               NhlTBoolean             RCSG    |
|       CnMonoLevelFlag                 False                   |
|---------------------------------------------------------------|
| cnLevelFlag                   NhlTcnLevelUseMode      RCSG    |
|       CnLevelFlags                    "LineOnly"              |
|---------------------------------------------------------------|
| cnLevelFlags                  NhlTcnLevelUseModeGenArray RCSG |
|       CnLevelFlags                    <dynamic>               |
|---------------------------------------------------------------|
| cnLinesOn                     NhlTBoolean             RCSG    |
|       CnLinesOn                       True                    |
|---------------------------------------------------------------|
| cnLineDrawOrder               NhlTDrawOrder           RCSG    |
|       CnLineDrawOrder                 "Draw"                  |
|---------------------------------------------------------------|
| cnMonoLineColor               NhlTBoolean             RCSG    |
|       CnMonoLineColor                 True                    |
|---------------------------------------------------------------|
| cnLineColor                   NhlTColorIndex          RCSG    |
|       LineColor                       "Foreground"            |
|---------------------------------------------------------------|
| cnSpanLinePalette               NhlTBoolean             RCSG    |
|       CnSpanLinePalette                 True                    |
|---------------------------------------------------------------|
| cnLinePalette                  NhlTColorDefinitionGenArray  RCSG    |
|       CnLinePalette                    <None>               |
|---------------------------------------------------------------|
| cnLineColors                  NhlTColorIndexGenArray  RCSG    |
|       CnLineColors                    <dynamic>               |
|---------------------------------------------------------------|
| cnMonoLineDashPattern         NhlTBoolean             RCSG    |
|       CnMonoLineDashPattern           True                    |
|---------------------------------------------------------------|
| cnLineDashPattern             NhlTDashIndex           RCSG    |
|       LineDashPattern                 "SolidLine"             |
|---------------------------------------------------------------|
| cnLineDashPatterns            NhlTDashIndexGenArray   RCSG    |
|       CnLineDashPatterns              <dynamic>               |
|---------------------------------------------------------------|
| cnMonoLineThickness           NhlTBoolean             RCSG    |
|       CnMonoLineThickness             True                    |
|---------------------------------------------------------------|
| cnLineThicknessF              NhlTFloat               RCSG    |
|       LineThicknessF                 	1.0                     |
|---------------------------------------------------------------|
| cnLineThicknesses             NhlTFloatGenArray       RCSG    |
|       CnLineThicknesses               1.0 for all elements    |
|---------------------------------------------------------------|
| cnLineDashSegLenF             NhlTFloat               RCSG    |
|       LineDashSegLenF                 0.15                    |
|---------------------------------------------------------------|
| cnFillOn                      NhlTBoolean             RCSG    |
|       CnFillOn                        False                   |
|---------------------------------------------------------------|
| cnFillMode                    NhlTcnFillMode          RCSG    |
|       CnFillMode                      False                   |
|---------------------------------------------------------------|
| cnFillDrawOrder               NhlTDrawOrder           RCSG    |
|       CnFillDrawOrder                 "Draw"                  |
|---------------------------------------------------------------|
| cnFillBackgroundColor         NhlTColorIndex          RCSG    |
|       FillBackgroundColor             "Transparent"           |
|---------------------------------------------------------------|
| cnMonoFillColor               NhlTBoolean             RCSG    |
|       CnMonoFillColor                 False                   |
|---------------------------------------------------------------|
| cnFillColor                   NhlTColorIndex          RCSG    |
|       FillColor                       "Foreground"            |
|---------------------------------------------------------------|
| cnSpanFillColor               NhlTBoolean             RCSG    |
|       CnSpanFillColor                 True                    |
|---------------------------------------------------------------|
| cnFillPalette                  NhlTColorDefinitionGenArray  RCSG    |
|       CnFillPalette                    <None>               |
|---------------------------------------------------------------|
| cnFillColors                  NhlTColorIndexGenArray  RCSG    |
|       CnFillColors                    <dynamic>               |
|---------------------------------------------------------------|
| cnMonoFillPattern             NhlTBoolean             RCSG    |
|       CnMonoFillPattern               True                    |
|---------------------------------------------------------------|
| cnFillPattern                 NhlTFillIndex           RCSG    |
|       FillPattern                     "SolidFill"             |
|---------------------------------------------------------------|
| cnFillPatterns                NhlTFillIndexGenArray   RCSG    |
|       CnFillPatterns                  <dynamic>               |
|---------------------------------------------------------------|
| cnFillDotSizeF                NhlTFloat               RCSG    |
|       DotSizeF                        0.0                     |
|---------------------------------------------------------------|
| cnMonoFillScale               NhlTBoolean             RCSG    |
|       CnMonoFillScale                 True                    |
|---------------------------------------------------------------|
| cnFillScaleF                  NhlTFloat               RCSG    |
|       FillScaleF                      1.0                     |
|---------------------------------------------------------------|
| cnFillScales                  NhlTFloatGenArray       RCSG    |
|       CnFillScales                    1.0 for all elements    |
|---------------------------------------------------------------|
| cnCellFillEdgeColor           NhlTColorIndex          RCSG    |
|       EdgeColor                       "Transparent"           |
|---------------------------------------------------------------|
| cnCellFillMissingValEdgeColor NhlTColorIndex          RCSG    |
|       EdgeColor                       "Transparent"           |
|---------------------------------------------------------------|
| cnRasterModeOn		NhlTBoolean             RCSG    |
|       CnRasterModeOn                  False                   |
|---------------------------------------------------------------|
| cnRasterSmoothingOn		NhlTBoolean             RCSG    |
|       CnRasterSmoothingOn             False                   |
|---------------------------------------------------------------|
| cnRasterMinCellSizeF          NhlTFloat		RCSG    |
|       CnRasterMinCellSizeF            0.001                   |
|---------------------------------------------------------------|
| cnRasterSampleFactorF		NhlTFloat		RCSG    |
|       CnRasterSampleFactorF           False                   |
|---------------------------------------------------------------|
| cnRasterCellSizeF		NhlTFloat		RCSG    |
|       CnRasterCellSizeF               <dynamic>               |
|---------------------------------------------------------------|
| cnLabelDrawOrder              NhlTDrawOrder           RCSG    |
|       CnLabelDrawOrder                "Draw"                  |
|---------------------------------------------------------------|
| cnLabelMasking                NhlTBoolean             RCSG    |
|       CnLabelMasking                  False                   |
|---------------------------------------------------------------|
| cnLowUseHighLabelRes          NhlTBoolean             RCSG    |
|       CnLowUseHighLabelRes            False                   |
|---------------------------------------------------------------|
| cnHighUseLineLabelRes         NhlTBoolean             RCSG    |
|       CnHighUseLineLabelRes           False                   |
|---------------------------------------------------------------|
| cnConstFUseInfoLabelRes       NhlTBoolean             RCSG    |
|       CnConstFUseInfoLabelRes         False                   |
|---------------------------------------------------------------|
| cnHighLowLabelOverlapMode NhlTcnHighLowLabelOverlapMode RCSG  |
|       CnHighLowLabelOverlapMode       "IgnoreOverlap"         |
|---------------------------------------------------------------|
| cnLabelScalingMode            NhlTScalingMode         RCSG    |
|       CnLabelScalingMode              "ScaleFactor"           |
|---------------------------------------------------------------|
| cnLabelScaleValueF            NhlTFloat               RCSG    |
|       CnLabelScaleValueF              1.0                     |
|---------------------------------------------------------------|
| cnLabelScaleFactorF           NhlTFloat                  G    |
|       CnLabelScaleFactorF             <dynamic>               |
|---------------------------------------------------------------|
| cnMaxDataValueFormat          NhlTString              RCSG    |
|       CnMaxDataValueFormat            NULL                    |
|---------------------------------------------------------------|
| cnLineLabelsOn                NhlTBoolean             RCSG    |
|       PlotLabelsOn                    True                    |
|---------------------------------------------------------------|
| cnExplicitLineLabelsOn	NhlTBoolean             RCSG    |
|       CnExplicitLineLabelsOn		False                   |
|---------------------------------------------------------------|
| cnLineLabelPlacementMode NhlTcnLineLabelPlacementMode    RCSG |
|       CnLineLabelPlacementMode        "Randomized"            |
|---------------------------------------------------------------|
| cnLineLabelDensityF           NhlTFloat               RCSG    |
|      CnLineLabelDensityF              0.0                     |
|---------------------------------------------------------------|
| cnLineLabelInterval           NhlTFloat               RCSG    |
|       CnLineLabelInterval             2                       |
|---------------------------------------------------------------|
| cnLineLabelCount              NhlTInteger                G    |
|       CnLineLabelCount                0                       |
|---------------------------------------------------------------|
| cnLineLabelStrings            NhlTStringGenArray      RCSG    |
|       CnLineLabelStrings              <dynamic>               |
|---------------------------------------------------------------|
| cnMonoLineLabelFontColor      NhlTBoolean             RCSG    |
|       CnMonoLineLabelFontColor        True                    |
|---------------------------------------------------------------|
| cnLineLabelFontColor          NhlTColorIndex          RCSG    |
|       FontColor                       "Foreground"            |
|---------------------------------------------------------------|
| cnLineLabelFontColors         NhlTColorIndexGenArray  RCSG    |
|       CnLineLabelFontColors           <dynamic>               |
|---------------------------------------------------------------|
| cnLineLabelFormat             NhlTString              RCSG    |
|       NumberFormat                    "*+g"                   |
|---------------------------------------------------------------|
| cnLineLabelFontHeightF        NhlTFloat               RCSG    |
|       FontHeightF                     <dynamic>               |
|---------------------------------------------------------------|
| cnLineLabelFont               NhlTFont                RCSG    |
|       Font                            "pwritx"                |
|---------------------------------------------------------------|
| cnLineLabelFontAspectF        NhlTFloat               RCSG    |
|       FontAspectF                     1.3125                  |
|---------------------------------------------------------------|
| cnLineLabelFontThicknessF     NhlTFloat               RCSG    |
|       FontThicknessF                  1.0                     |
|---------------------------------------------------------------|
| cnLineLabelFontQuality	NhlTFontQuality		RCSG	|
|       FontQuality                     "High"                  |
|---------------------------------------------------------------|
| cnLineLabelConstantSpacingF   NhlTFloat               RCSG    |
|       TextConstantSpacingF            0.0                     |
|---------------------------------------------------------------|
| cnLineLabelAngleF             NhlTFloat               RCSG    |
|       CnLineLabelAngleF               -1.0                    |
|---------------------------------------------------------------|
| cnLineLabelFuncCode           NhlTCharacter           RCSG    |
|       TextFuncCode                    ':'                     |
|---------------------------------------------------------------|
| cnLineLabelBackgroundColor    NhlTColorIndex          RCSG    |
|       FillBackgroundColor             "Background"            |
|---------------------------------------------------------------|
| cnLineLabelPerimOn            NhlTInteger             RCSG    |
|       EdgesOn                         True                    |
|---------------------------------------------------------------|
| cnLineLabelPerimSpaceF        NhlTFloat               RCSG    |
|       EdgeBorderWidthF                0.33                    |
|---------------------------------------------------------------|
| cnLineLabelPerimColor         NhlTColorIndex          RCSG    |
|       EdgeColor                       "Foreground"            |
|---------------------------------------------------------------|
| cnLineLabelPerimThicknessF    NhlTFloat               RCSG    |
|       EdgeThicknessF                  1.0                     |
|---------------------------------------------------------------|
| cnHighLabelsOn                NhlTBoolean             RCSG    |
|       PlotLabelsOn                    False                   |
|---------------------------------------------------------------|
| cnHighLabelCount              NhlTInteger                G    |
|       CnHighLabelCount                0                       |
|---------------------------------------------------------------|
| cnHighLabelString             NhlTString              RCSG    |
|       CnHighLabelString               NULL                    |
|---------------------------------------------------------------|
| cnHighLabelFormat             NhlTString              RCSG    |
|       NumberFormat                    "*+g"                   |
|---------------------------------------------------------------|
| cnHighLabelFontHeightF        NhlTFloat               RCSG    |
|       FontHeightF                     <dynamic>               |
|---------------------------------------------------------------|
| cnHighLabelFont               NhlTFont                RCSG    |
|       Font                            "pwritx"                |
|---------------------------------------------------------------|
| cnHighLabelFontColor          NhlTColorIndex          RCSG    |
|       FontColor                       "Foreground"            |
|---------------------------------------------------------------|
| cnHighLabelFontAspectF        NhlTFloat               RCSG    |
|       FontAspectF                     1.3125                  |
|---------------------------------------------------------------|
| cnHighLabelFontThicknessF     NhlTFloat               RCSG    |
|       FontThicknessF                  1.0                     |
|---------------------------------------------------------------|
| cnHighLabelFontQuality	NhlTFontQuality		RCSG	|
|       FontQuality                     "High"                  |
|---------------------------------------------------------------|
| cnHighLabelConstantSpacingF   NhlTFloat               RCSG    |
|       TextConstantSpacingF            0.0                     |
|---------------------------------------------------------------|
| cnHighLabelAngleF             NhlTFloat               RCSG    |
|       TextAngleF                      0.0                     |
|---------------------------------------------------------------|
| cnHighLabelFuncCode           NhlTCharacter           RCSG    |
|       TextFuncCode                    ':'                     |
|---------------------------------------------------------------|
| cnHighLabelBackgroundColor    NhlTColorIndex          RCSG    |
|       FillBackgroundColor             "Background"            |
|---------------------------------------------------------------|
| cnHighLabelPerimOn            NhlTInteger             RCSG    |
|       EdgesOn                         True                    |
|---------------------------------------------------------------|
| cnHighLabelPerimSpaceF        NhlTFloat               RCSG    |
|       EdgeBorderWidthF                0.33                    |
|---------------------------------------------------------------|
| cnHighLabelPerimColor         NhlTColorIndex          RCSG    |
|       EdgeColor                       "Foreground"            |
|---------------------------------------------------------------|
| cnHighLabelPerimThicknessF    NhlTFloat               RCSG    |
|       EdgeThicknessF                  1.0                     |
|---------------------------------------------------------------|
| cnLowLabelsOn                 NhlTBoolean             RCSG    |
|       PlotLabelsOn                    False                   |
|---------------------------------------------------------------|
| cnLowLabelCount               NhlTInteger                G    |
|       CnLowLabelCount                 0                       |
|---------------------------------------------------------------|
| cnLowLabelString              NhlTString              RCSG    |
|       CnLowLabelString                NULL                    |
|---------------------------------------------------------------|
| cnLowLabelFormat              NhlTString              RCSG    |
|       NumberFormat                    "*+g"                   |
|---------------------------------------------------------------|
| cnLowLabelFontHeightF         NhlTFloat               RCSG    |
|       FontHeightF                     <dynamic>               |
|---------------------------------------------------------------|
| cnLowLabelFont                NhlTFont                RCSG    |
|       Font                            "pwritx"                |
|---------------------------------------------------------------|
| cnLowLabelFontColor           NhlTColorIndex          RCSG    |
|       FontColor                       "Foreground"            |
|---------------------------------------------------------------|
| cnLowLabelFontAspectF         NhlTFloat               RCSG    |
|       FontAspectF                     1.3125                  |
|---------------------------------------------------------------|
| cnLowLabelFontThicknessF      NhlTFloat               RCSG    |
|       FontThicknessF                  1.0                     |
|---------------------------------------------------------------|
| cnLowLabelFontQuality		NhlTFontQuality		RCSG	|
|       FontQuality                     "High"                  |
|---------------------------------------------------------------|
| cnLowLabelConstantSpacingF    NhlTFloat               RCSG    |
|       TextConstantSpacingF            0.0                     |
|---------------------------------------------------------------|
| cnLowLabelAngleF              NhlTFloat               RCSG    |
|       TextAngleF                      0.0                     |
|---------------------------------------------------------------|
| cnLowLabelFuncCode            NhlTCharacter           RCSG    |
|       TextFuncCode                    ':'                     |
|---------------------------------------------------------------|
| cnLowLabelBackgroundColor     NhlTColorIndex          RCSG    |
|       FillBackgroundColor             "Background"            |
|---------------------------------------------------------------|
| cnLowLabelPerimOn             NhlTInteger             RCSG    |
|       EdgesOn                         True                    |
|---------------------------------------------------------------|
| cnLowLabelPerimSpaceF         NhlTFloat               RCSG    |
|       EdgeBorderWidthF                0.33                    |
|---------------------------------------------------------------|
| cnLowLabelPerimColor          NhlTColorIndex          RCSG    |
|       EdgeColor                       "Foreground"            |
|---------------------------------------------------------------|
| cnLowLabelPerimThicknessF     NhlTFloat               RCSG    |
|       EdgeThicknessF                  1.0                     |
|---------------------------------------------------------------|
| cnInfoLabelOn                 NhlTBoolean             RCSG    |
|       AnnotationLabelsOn              True                    |
|---------------------------------------------------------------|
| cnInfoLabelString             NhlTString              RCSG    |
|       CnInfoLabelString               NULL                    |
|---------------------------------------------------------------|
| cnInfoLabelFormat             NhlTString              RCSG    |
|       NumberFormat                    "*+g"                   |
|---------------------------------------------------------------|
| cnInfoLabelFontHeightF        NhlTFloat               RCSG    |
|       FontHeightF                     <dynamic>               |
|---------------------------------------------------------------|
| cnInfoLabelTextDirection      NhlTTextDirection       RCSG    |
|       TextDirection                   "Across"                |
|---------------------------------------------------------------|
| cnInfoLabelFont               NhlTFont                RCSG    |
|       Font                            "pwritx"                |
|---------------------------------------------------------------|
| cnInfoLabelFontColor          NhlTColorIndex          RCSG    |
|       FontColor                       "Foreground"            |
|---------------------------------------------------------------|
| cnInfoLabelFontAspectF        NhlTFloat               RCSG    |
|       FontAspectF                     1.3125                  |
|---------------------------------------------------------------|
| cnInfoLabelFontThicknessF     NhlTFloat               RCSG    |
|       FontThicknessF                  1.0                     |
|---------------------------------------------------------------|
| cnInfoLabelFontQuality	NhlTFontQuality		RCSG	|
|       FontQuality                     "High"                  |
|---------------------------------------------------------------|
| cnInfoLabelConstantSpacingF   NhlTFloat               RCSG    |
|       TextConstantSpacingF            0.0                     |
|---------------------------------------------------------------|
| cnInfoLabelAngleF             NhlTFloat               RCSG    |
|       TextAngleF                      0.0                     |
|---------------------------------------------------------------|
| cnInfoLabelFuncCode           NhlTCharacter           RCSG    |
|       TextFuncCode                    ':'                     |
|---------------------------------------------------------------|
| cnInfoLabelBackgroundColor    NhlTColorIndex          RCSG    |
|       FillBackgroundColor             "Background"            |
|---------------------------------------------------------------|
| cnInfoLabelPerimOn            NhlTInteger             RCSG    |
|       EdgesOn                         True                    |
|---------------------------------------------------------------|
| cnInfoLabelPerimSpaceF        NhlTFloat               RCSG    |
|       EdgeBorderWidthF                0.33                    |
|---------------------------------------------------------------|
| cnInfoLabelPerimColor         NhlTColorIndex          RCSG    |
|       EdgeColor                       "Foreground"            |
|---------------------------------------------------------------|
| cnInfoLabelPerimThicknessF    NhlTFloat               RCSG    |
|       EdgeThicknessF                  1.0                     |
|---------------------------------------------------------------|
| cnInfoLabelZone               NhlTInteger             RCSG    |
|       CnInfoLabelZone                 3                       |
|---------------------------------------------------------------|
| cnInfoLabelSide               NhlTPosition            RCSG    |
|       CnInfoLabelSide                 "Bottom"                |
|---------------------------------------------------------------|
| cnInfoLabelJust               NhlTJustification       RCSG    |
|       CnInfoLabelJust                 "TopRight"              |
|---------------------------------------------------------------|
| cnInfoLabelParallelPosF       NhlTFloat               RCSG    |
|       CnInfoLabelParallelPosF         1.0                     |
|---------------------------------------------------------------|
| cnInfoLabelOrthogonalPosF     NhlTFloat               RCSG    |
|       CnInfoLabelOrthogonalPosF       0.02                    |
|---------------------------------------------------------------|
| cnNoDataLabelOn               NhlTBoolean             RCSG    |
|       AnnotationLabelsOn              True                    |
|---------------------------------------------------------------|
| cnNoDataLabelString           NhlTString              RCSG    |
|       CnNoDataLabelString             NULL                    |
|---------------------------------------------------------------|
| cnConstFLabelOn               NhlTBoolean             RCSG    |
|       AnnotationLabelsOn              True                    |
|---------------------------------------------------------------|
| cnConstFLabelString           NhlTString              RCSG    |
|       CnConstFLabelString             NULL                    |
|---------------------------------------------------------------|
| cnConstFLabelFormat           NhlTString              RCSG    |
|       NumberFormat                    "*+g"                   |
|---------------------------------------------------------------|
| cnConstFLabelFontHeightF      NhlTFloat               RCSG    |
|       FontHeightF                     <dynamic>               |
|---------------------------------------------------------------|
| cnConstFLabelTextDirection    NhlTTextDirection       RCSG    |
|       TextDirection                   "Across"                |
|---------------------------------------------------------------|
| cnConstFLabelFont             NhlTFont                RCSG    |
|       Font                            "pwritx"                |
|---------------------------------------------------------------|
| cnConstFLabelFontColor        NhlTColorIndex          RCSG    |
|       FontColor                       "Foreground"            |
|---------------------------------------------------------------|
| cnConstFLabelFontAspectF      NhlTFloat               RCSG    |
|       FontAspectF                     1.3125                  |
|---------------------------------------------------------------|
| cnConstFLabelFontThicknessF   NhlTFloat               RCSG    |
|       FontThicknessF                  1.0                     |
|---------------------------------------------------------------|
| cnConstFLabelFontQuality	NhlTFontQuality		RCSG	|
|       FontQuality                     "High"                  |
|---------------------------------------------------------------|
| cnConstFLabelConstantSpacingF NhlTFloat               RCSG    |
|       TextConstantSpacingF            0.0                     |
|---------------------------------------------------------------|
| cnConstFLabelAngleF           NhlTFloat               RCSG    |
|       TextAngleF                      0.0                     |
|---------------------------------------------------------------|
| cnConstFLabelFuncCode         NhlTCharacter           RCSG    |
|       TextFuncCode                    ':'                     |
|---------------------------------------------------------------|
| cnConstFLabelBackgroundColor  NhlTColorIndex          RCSG    |
|       FillBackgroundColor             "Background"            |
|---------------------------------------------------------------|
| cnConstFLabelPerimOn          NhlTInteger             RCSG    |
|       EdgesOn                         True                    |
|---------------------------------------------------------------|
| cnConstFLabelPerimSpaceF      NhlTFloat               RCSG    |
|       EdgeBorderWidthF                0.33                    |
|---------------------------------------------------------------|
| cnConstFLabelPerimColor       NhlTColorIndex          RCSG    |
|       EdgeColor                       "Foreground"            |
|---------------------------------------------------------------|
| cnConstFLabelPerimThicknessF  NhlTFloat               RCSG    |
|       EdgeThicknessF                  1.0                     |
|---------------------------------------------------------------|
| cnConstFLabelZone             NhlTInteger             RCSG    |
|       CnConstFLabelZone               0                       |
|---------------------------------------------------------------|
| cnConstFLabelSide             NhlTPosition            RCSG    |
|       CnConstFLabelSide               "Bottom"                |
|---------------------------------------------------------------|
| cnConstFLabelJust             NhlTJustification       RCSG    |
|       CnConstFLabelJust               "CenterCenter"          |
|---------------------------------------------------------------|
| cnConstFLabelParallelPosF     NhlTFloat               RCSG    |
|       CnConstFLabelParallelPosF       0.0                     |
|---------------------------------------------------------------|
| cnConstFLabelOrthogonalPosF   NhlTFloat               RCSG    |
|       CnConstFLabelOrthogonalPosF     0.0                     |
|---------------------------------------------------------------|
| cnMissingValPerimOn           NhlTBoolean             RCSG    |
|       EdgesOn                         False                   |
|---------------------------------------------------------------|
| cnMissingValPerimGridBoundOn  NhlTBoolean             RCSG    |
|       CnMissingValPerimGridBoundOn    False                   |
|---------------------------------------------------------------|
| cnMissingValPerimThicknessF   NhlTFloat               RCSG    |
|       EdgeThicknessF                  1.0                     |
|---------------------------------------------------------------|
| cnMissingValPerimDashPattern  NhlTDashIndex           RCSG    |
|       EdgeDashPattern                 "SolidLine"             |
|---------------------------------------------------------------|
| cnMissingValPerimColor        NhlTColorIndex          RCSG    |
|       EdgeColor                       "Foreground"            |
|---------------------------------------------------------------|
| cnMissingValFillColor         NhlTColorIndex          RCSG    |
|       FillColor                       "Background"            |
|---------------------------------------------------------------|
| cnMissingValFillPattern       NhlTInteger             RCSG    |
|       FillPattern                     "HollowFill"            |
|---------------------------------------------------------------|
| cnMissingValFillScaleF        NhlTFloat               RCSG    |
|       FillScaleF                      1.0                     |
|---------------------------------------------------------------|
| cnGridBoundPerimOn            NhlTInteger             RCSG    |
|       EdgesOn                         False                   |
|---------------------------------------------------------------|
| cnGridBoundPerimThicknessF    NhlTFloat               RCSG    |
|       EdgeThicknessF                  1.0                     |
|---------------------------------------------------------------|
| cnGridBoundPerimDashPattern   NhlTDashIndex           RCSG    |
|       EdgeDashPattern                 "SolidLine"             |
|---------------------------------------------------------------|
| cnGridBoundPerimColor         NhlTColorIndex          RCSG    |
|       EdgeColor                       "Foreground"            |
|---------------------------------------------------------------|
| cnOutOfRangePerimOn           NhlTInteger             RCSG    |
|       EdgesOn                         False                   |
|---------------------------------------------------------------|
| cnOutOfRangePerimThicknessF   NhlTFloat               RCSG    |
|       EdgeThicknessF                  1.0                     |
|---------------------------------------------------------------|
| cnOutOfRangePerimDashPattern  NhlTDashIndex           RCSG    |
|       EdgeDashPattern                 "SolidLine"             |
|---------------------------------------------------------------|
| cnOutOfRangePerimColor        NhlTColorIndex          RCSG    |
|       EdgeColor                       "Foreground"            |
|---------------------------------------------------------------|
| cnSmoothingOn                 NhlTBoolean             RCSG    |
|       CnSmoothingOn                   False                   |
|---------------------------------------------------------------|
| cnSmoothingTensionF           NhlTFloat               RCSG    |
|       CnSmoothingTensionF             -2.5                    |
|---------------------------------------------------------------|
| cnSmoothingDistanceF          NhlTFloat               RCSG    |
|       CnSmoothingDistanceF            0.01                    |
|---------------------------------------------------------------|
| cnMaxPointDistanceF		NhlTFloat               RCSG    |
|       CnMaxPointDistanceF		0.05                    |
|---------------------------------------------------------------|
| cnExplicitLabelBarLabelsOn    NhlTBoolean             RCSG    |
|       CnExplicitLabelBarLabelsOn      False                   |
|---------------------------------------------------------------|
| cnLabelBarEndLabelsOn         NhlTBoolean             RCSG    |
|       CnLabelBarEndLabelsOn           False                   |
|---------------------------------------------------------------|
| cnLabelBarEndStyle            NhlTLabelBarEndStyle    RCSG    |
|       CnLabelBarEndStyle              "IncludeOuterBoxes"     |
|---------------------------------------------------------------|
| cnExplicitLegendLabelsOn	NhlTBoolean             RCSG    |
|       CnExplicitLegendLabelsOn        False                   |
|---------------------------------------------------------------|
| cnLegendLevelFlags            NhlTcnLevelUseModeGenArray RCSG |
|       CnLegendLevelFlags              NULL                    |
|---------------------------------------------------------------|
| cnConpackParams               NhlTStringGenArray      RCS     |
|       CnConpackParams                 NULL                    |
|---------------------------------------------------------------|
| cnFixFillBleed                NhlTBoolean             RCS     |
|       CnFixFillBleed                  NULL                    |
+---------------------------------------------------------------+

Data specific resources

The ContourPlot class does not currently use any data specific resources.

Composite resources

Transformation resources

Transformation class resources specify the extent, direction and grid type of the data coordinate system. The Transformation class is the superclass of all classes used to perform data transformations, and you can access all its resources. However, note that ContourPlot intercepts its resources, as follows:
  • trXMinF
    By default trXMinF is set to the minimum data coordinate value along the X Axis, as determined from the contents of the ScalarField object.
  • trXMaxF
    By default trXMaxF is set to the maximum data coordinate value along the X Axis, as determined from the contents of the ScalarField object.
  • trXReverse
    By default trXReverse is set based on the direction of the X Axis implied by the contents of the ScalarField object.
  • trYMinF
    By default trYMinF is set to the minimum data coordinate value along the Y Axis, as determined from the contents of the ScalarField object.
  • trYMaxF
    By default trYMaxF is set to the maximum data coordinate value along the Y Axis, as determined from the contents of the ScalarField object.
  • trYReverse
    By default trYReverse is set based on the direction of the Y Axis implied by the contents of the ScalarField object.
  • trGridType
    If trGridType is set to TriangularMesh ContourPlot does not alter the set value. If cnScalarFieldData is set using a MeshScalarField object, trGridType is forced to TriangularMesh. Otherwise, If cnScalarFieldData is set using a regular ScalarField object, trGridType is forced to LogLin if sfXArray and sfYArray both have NULL values. It is forced to Irregular if sfXArray and/or sfYArray contain 1D coordinate arrays. If sfXArray and sfYArray contain 2D coordinate arrays, trGridType defaults to Spherical but it can optionally be set to Curvilinear or TriangularMesh.

LogLinTransformation resources

The ContourPlot class uses the LogLinTransformation to handle its transformations as long as neither of the ScalarField array resources, sfXArray or sfYArray, is set. LogLinTransformation has resources for selecting between linear and logarithmic coordinates for each axis.

You can access all LogLinTransformation resources. However, note that ContourPlot intercepts LogLinTransformation resources, as follows:

  • trXLog
    ContourPlot issues a warning if trXLog is set True when the set value of trXMinF is less than or equal to 0.0. In this case it resets trXLog to False. If the IrregularTransformation resource trXAxisType is set, ContourPlot sets trXLog True if trXAxisType is set to LogAxis. If trXAxisType is set to any other value, it sets trXLog False.
  • trYLog
    ContourPlot issues a warning if trYLog is set True when the set value of trYMinF is less than or equal to 0.0. In this case it resets trYLog to False. If the IrregularTransformation resource trYAxisType is set, ContourPlot sets trYLog True if trYAxisType is set to LogAxis. If trYAxisType is set to any other value, it sets trYLog False.

IrregularTransformation resources

ContourPlot automatically uses the IrregularTransformation to handle its transformations if the ScalarField array resources sfXArray and/or sfYArray are set with one-dimensional arrays, implying that one or both of the coordinate axes is irregularly spaced.

All Transformation superclass resources are accessible. However, ContourPlot blocks access to all resources specific to the IrregularTransformation except for:

and for the following intercepted resources:
  • trXAxisType
    If the ScalarField resource sfXArray is non-NULL and trXAxisType is set to any value other than IrregularAxis, ContourPlot switches to a coordinate extent bounded by 0 and the length of the X-Axis dimension minus one. If trXAxisType is not set, but the LogLinTransformation resource trXLog is set, ContourPlot sets trXAxisType to LogAxis if trXLog is True; if trXLog is False, it changes trXAxisType to LinearAxis if it had been set to LogAxis and leaves it unchanged otherwise. trXAxisType can be set to LogAxis without error only when the X-Axis coordinate extent as passed from the ScalarField is entirely positive. If this is not the case, trXAxisType will default to LinearAxis.

    V4.1 Status Note 1

  • trYAxisType
    If the ScalarField resource sfYArray is non-NULL and trYAxisType is set to any value other than IrregularAxis, ContourPlot switches to a coordinate extent bounded by 0 and the length of the Y-Axis dimension minus one. If trYAxisType is not set, but the LogLinTransformation resource trYLog is set, ContourPlot sets trYAxisType to LogAxis if trYLog is True; if trYLog is False, it changes trYAxisType to LinearAxis if it had been set to LogAxis and leaves it unchanged otherwise. trYAxisType can be set to LogAxis without error only when the Y-Axis coordinate extent as passed from the ScalarField is entirely positive. If this is not the case, trYAxisType will default to LinearAxis.

    V4.1 Status Note 1

CurvilinearTransformation resources

ContourPlot uses the CurvilinearTransformation to handle its transformations if the ScalarField array resources sfXArray and sfYArray are set with two-dimensional arrays and the Transformation class resource trGridType is set to Curvilinear. The CurvilinearTransformation class has no user-accessible resources.

SphericalTransformation resources

ContourPlot uses the SphericalTransformation to handle its transformations if the ScalarField array resources sfXArray and sfYArray are set with two-dimensional arrays and the Transformation class resource trGridType is set to Spherical. The SphericalTransformation class has no user-accessible resources.

TriangularMeshTransformation resources

ContourPlot uses the TriangularMeshTransformation to handle its transformations if cnScalarFieldData is set using a MeshScalarField object, or otherwise if the Transformation class resource trGridType is explicitly set to TriangularMesh. The TriangularMeshTransformation class has no user-accessible resources.

PlotManager resources

If tfPlotManagerOn is True when a ContourPlot object is created, you can access all PlotManager resources. However, note that ContourPlot intercepts certain PlotManager resources, as follows: You can also access resources for any of composite classes of the PlotManager class. However, the PlotManager class modifies the access and behavior of some of the resources belonging to these classes, as follows: The ContourPlot class itself also modifies the access and behavior of a number of LabelBar and Legend resources.
Additional modifications to LabelBar resources
The ContourPlot class disables a number of LabelBar resources, since it sets them automatically based on the current values of certain relevant ContourPlot resources. The disabled resources include: In addition, the ContourPlot class intercepts certain LabelBar resources, as follows:
Additional modifications to Legend resources
The ContourPlot object disables a number of Legend resources, since it sets them automatically based on the current values of certain relevant ContourPlot resources. The disabled resources include: In addition, the ContourPlot class intercepts two Legend resources, as follows:

Superclass resources

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


Description

The ContourPlot object draws a contour plot from two-dimensional data provided by an object belonging to the ScalarField class. The plot may consist only of lines, or may be filled using color and/or fill patterns to distinguish the various contour regions. You can control how the contour levels are selected. Selected contour levels, as well as regional high and low points, may be labeled. You can cause a number of annotational items to appear, including an informational label, tick marks, titles, a labelbar, and a line legend. These items automatically adjust themselves to the current state of the ContourPlot object. You may also differentiate certain special areas with unique lines or fill, and control to some extent the algorithms used to generate the contour lines.

The ContourPlot object provides what may seem like an overwhelming number of resources, but keep in mind that generally you will need to use only a few of them. In fact, there is only one resource you need to set explicitly in order to generate a meaningful contour plot. You need to focus only on resources that modify the features of the ContourPlot object that are important to you. All the others will default to generally usable values. Moreover, resources that provide control over related attributes of the various ContourPlot elements have related names. As an example, all resources that specify the color of the text used for the various labels available in the ContourPlot object have names of the form cn...LabelFontColor(s), where the plural form is used for resources that represent arrays.

Data input

The only resource you must set in order to generate an actual contour plot is cnScalarFieldData. This resource specifies the id of a pre-existing object belonging to the ScalarField class or its sub-class MeshScalarField. Note that both regular ScalarField and MeshScalarField objects belong to the ScalarField class. Therefore they are both ScalarField objects.

Use a regular ScalarField object for topologically rectangular gridded data. This is data that can be specified using a two-dimensional array with the common property that, for any interior element of the array e[j,i], a line through the location of the 8 elements e[j +/- 1, i +/- 1] would separate the element e[j,i] from the locations in data space of all other elements. You may define the coordinate space of the ScalarField data array using 1 or 2 dimensional coordinate arrays, or simply by setting the start and end locations along each axis. If you do not set any coordinate array resources the coordinate space defaults to the the array index extents.

Use a MeshScalarField if the data cannot be specified using a two-dimensional array as described above, but you can specify the location of each data element explicitly. You must set each data value and its location along the X and Y Axes as the corresponding elements of three one-dimensional arrays. You may explicitly or implicitly specify the mesh to be created from the data nodes using MeshScalarField resources. If you do not specify the mesh, ContourPlot generates it by calculating a Delauney triangulation in the projection plane, using Jonathan Shewchuk's Triangle package. A ScalarField object accepts data in a variety of types and configurations and allows you to specify how it is to be interpreted. As received by the ContourPlot object, the data are accompanied by information specifying the extents of the data in the data coordinate system and the minimum and maximum data values.

Coordinate transformations

ContourPlot intrinsically supports linear, logarithmic, and irregular rectangular gridded data coordinate spaces.

ContourPlot also supports topologically rectangular grids defined using 2D coordinate arrays.

If the cnScalarFieldData is set using a MeshScalarField object, ContourPlot supports non-rectangular data spaces. These may include pre-defined triangular meshes or simply consist of singly-dimensioned data and location arrays.

ContourPlot instantiates child objects to manage transformations between the data coordinate system and NDC space. The LogLinTransformation manages linear and logarithmic transformations, and the IrregularTransformation manages the transformation if one or both axes are irregularly spaced. If the grid is defined using 2D coordinate arrays, ContourPlot instantiates either the CurvilinearTransformation or the SphericalTransformation to handle the transformations. ContourPlot uses the TriangularMeshTransformation to manage transformations for non-rectangular data meshes. Optionally, the TriangularMeshTransformation can be used for rectangular grids as well.

By default the data coordinate extents are based on the extents of the supplied ScalarField object data, but you may adjust them using resources belonging to the Transformation super-class.

Use of the LogLinTransformation object

ContourPlot uses a LogLinTransformation object as long as the ScalarField resources sfXArray and sfYArray are both NULL. The coordinate extents of a linear axis may arbitrarily intersect or encompass the data extent. If you set a logarithmic axis, then the coordinate extent of that axis must be entirely positive, but otherwise may intersect or extend beyond the data extent.

Use of the IrregularTransformation object

If either of the ScalarField coordinate array resources sfXArray and sfYArray are non-NULL and they are not set with 2D arrays, ContourPlot uses an IrregularTransformation object. Note that ContourPlot treats an axis with an associated coordinate array as irregular even if the coordinate array actually has evenly spaced values. ContourPlot represents an irregular axis not by stretching and compressing various regions of the plot, but by displaying it with irregularly spaced tick marks.

In addition to a small performance penalty, there are some restrictions associated with use of the IrregularTransformation object. Although you may limit the coordinate extent to a subspace of the data coordinate extent of the ScalarField object data, you are not allowed to define a coordinate range that extends outside the range of the data coordinates of an irregular axis. Using the IrregularTransformation resources trXAxisType or trYAxisType, it is possible to set an irregular axis to LinearAxis or even, under certain conditions, to LogAxis, but the results are probably not what you want. Since ContourPlot does not intrinsically support a linearization transformation for irregularly spaced data, it can only switch to a linear system by replacing the data coordinates with array index coordinates, which are, in fact, linearly spaced. To properly transform irregularly spaced data into a linear or logarithmic coordinate system, you must use the overlay mechanism (V4.1 Status Note 1).

Use of the CurvilinearTransformation object

If both the ScalarField coordinate array resources sfXArray and sfYArray are set using 2D coordinate arrays and the Transformation class resource trGridType is set to Curvilinear ContourPlot uses a CurvilinearTransformation object. As with the IrregularTransformation you cannot set the coordinate range outside, the range of the data. Also, since X and Y coordinate locations both vary along the grid edges, tickmarks are disabled. In order to place the the data in context, you need to overlay the ContourPlot on another plot such as a mapplot.

Use of the SphericalTransformation object

If both the ScalarField coordinate array resources sfXArray and sfYArray are set using 2D coordinate arrays and the Transformation class resource trGridType is set to Spherical ContourPlot uses a CurvilinearTransformation object. As with the IrregularTransformation you cannot set the coordinate range outside the range of the data. Also, since X and Y coordinate locations both vary along the grid edges, tickmarks are disabled. In order to place the the data in context, you need to overlay the ContourPlot on another plot such as a mapplot.

Use of the TriangularMeshTransformation object

If you set cnScalarFieldData using a MeshScalarField object, ContourPlot uses the TriangularMeshTransformation to perform transformations from data space into the plotting space. Optionally, if you set the Transformation resource trGridType to TriagularMesh, ContourPlot can use the TriangularMeshTransformation for normal ScalarField data as well. The TriangularMeshTransformation always transforms the data space into a linear cartesian coordinate space, meaning it will linearize irregularly gridded or non-rectangular mesh data without requiring an overlay. In contrast to the behavior of SphericalTransformation and CurvilinearTransformation, tickmarks are enabled for the TriangularMeshTransformation. You can overlay a ContourPlot that uses the TriangularMeshTransformation in the normal way.

Besides its primary use as the transformation engine for non-rectangular mesh data, the TriangularMeshTransformation may have performance advantages for some types of rectangular grids. Also, it can be used for for certain grids, such as 2D grids with missing values in the coordinate arrays, when the other Transformation classes would fail.

Currently, there are a few unresolved issues with the TriangularMeshTransformation. When overlaid on a mapplot, for certain projections, the edges of the plot may have a ragged appearance and not completely fill the projected data boundaries. This is particularly true when cnFillMode is set to RasterFill, but can also be the case for AreaFill if cnScalarFieldData is set with a MeshScalarField object.

Prior to version 6.2.0, when a MeshScalarField object provided the data, the CellFill mode was unavailable. Now it is possible to use the CellFill mode provided the vertices of each cell are specified using the sfXCellBounds and sfYCellBounds resources.

Overlays

By overlaying a ContourPlot on various types of base plot, it is possible to map contours of arbitrary ScalarField data into a variety of coordinate spaces. You can overlay a ContourPlot on a mapplot to transform the data into any of 10 different map projections. You can overlay contours of irregularly gridded data on a loglinplot to have the data appear in a linear or logarithmic coordinate space. You can also overlay any contoured data on an irregularplot, either to project regularly gridded data into an irregular coordinate space, or perhaps to overcome the data extent limitations of the ContourPlot's intrinsic IrregularTransformation object. You can overlay a ContourPlot on any type of base plot in a one-step operation using the NhlAddOverlay function.

Controlling draw order

The ContourPlot object allows you to control the order in which its major elements are drawn. You may separately control the drawing order for lines, fill, and labels using the resources cnLineDrawOrder, cnFillDrawOrder, and cnLabelDrawOrder. There are three drawing phases: the predraw phase, the draw phase, and the postdraw phase. By default, ContourPlot draws all plot elements during the draw phase: first the fill, then the lines, and finally the labels. When a ContourPlot is drawn by itself, this is usually a reasonable order that results in the important features of the plot being visible. However, when a ContourPlot object is overlaid over a base plot, particularly when masking is involved, you often need to adjust the drawing order to ensure that the features you want to see remain visible.

Note that annotations associated with the ContourPlot, including the informational and constant field labels, are always drawn during the postdraw phase.

Controlling annotations

The ContourPlot object supports three kinds of annotations: those that it creates on its own, the informational and constant field embedded annotations; those that are created by its composite PlotManager object, including Title, Tickmark, LabelBar, and Legend intrinsic annotations; and finally arbitrary user-defined external annotations. The Transform class resource tfPlotManagerOn must be set True (its default value) when the ContourPlot object is created in order for the intrinsic or external annotations to be available. The informational label (and the constant field label under the appropriate conditions) appear by default. Assuming tfPlotManagerOn is set True, tick marks also appear by default. Titles appear if you set the appropriate title string resource to any non-NULL string value. In order for a labelbar or legend to appear, you must set the PlotManager resources pmLabelBarDisplayMode or pmLegendDisplayMode to the values Conditional or Always.

Except for the tick marks and the titles, all these annotations are positioned using resources that follow the PlotManager Location Control Model. The ContourPlot object provides resources for controlling attributes of the informational and the constant field labels. You can control the resources of the objects that render the intrinsic annotations directly, subject to some access and behavioral modifications imposed by the PlotManager object and by the ContourPlot object itself. These objects are the TickMark object, the Title object, the LabelBar object, and theLegend object.

Selecting levels

By appropriately setting the cnLevelSelectionMode resource, you can choose from four level-selection modes to set up the levels used in the contour plot. The default mode, AutomaticLevels, is easy to use. It selects a "nice" spacing starting from the smallest relatively round number greater than the minimum data value, such that the number of contour levels is as close as possible to, but less than, the value of the resource cnMaxLevelCount. EqualSpacedLevels mode defines exactly cnMaxLevelCount levels spaced evenly from the data minimum value to the data maximum value. In ManualLevels mode, you set the maximum and minimum contour levels using the resources cnMinLevelValF and cnMaxLevelValF with a spacing defined by the resource cnLevelSpacingF. Finally, Explicit mode allows you to define the level values yourself by setting the array resource cnLevels. The ManualLevels and ExplicitLevels modes have the advantage that they are independent of the maximum and minimum values of the particular dataset you are contouring, and therefore can be used to enforce consistency in the contouring of a series of related datasets. ExplicitLevels is the only mode that allows you to establish variably spaced contour levels.

Once you have established the contour levels, you can retrieve the number of levels actually used by getting the value of the read-only resource cnLevelCount. Based on this value, you can set the cnLevelFlags enumerated array resource to specify whether you want lines only, labels only, lines and labels, or nothing at each individual contour level. This resource also has a scalar equivalent, cnLevelFlag, which you can set instead if you want all levels to appear the same way. If you set neither of these resources, then line labels automatically appear at contour levels spaced apart by the value of the resource cnLineLabelInterval, set by default to the value 2.

Contour lines

You can control whether contour lines appear at all by setting the boolean resource cnLinesOn. By default it is set True, meaning that contour lines will appear. If set False, no contour lines will appear regardless of the setting of cnLevelFlags or cnLevelFlag. You can control the color, the dash pattern and the thickness of contour lines individually or uniformly as a group. Individual control is through the array resources cnLineColors, cnLineDashPatterns, and cnLineThicknesses while control as a group is through the scalar resources cnLineColor, cnLineDashPattern, and cnLineThicknessF. You choose the scalar resources by setting the boolean resources cnMonoLineColor, cnMonoLineDashPattern, and cnMonoLineThickness True; you choose the array resources by setting them False. There is also a scalar resource, cnLineDashSegLenF that sets the segment length for all dash patterns used.

Contour fill

ContourPlot supports three methods for filling contour regions: area, raster and cell fill. Turn on fill for contour regions by setting the boolean resource cnFillOn True. Select the fill method by setting the enumerated resource cnFillMode to one of the three choices: AreaFill, RasterFill, or CellFill.

Area fill

For area fill, you can control the color, the fill pattern, and the scale of the fill pattern for all filled contour regions either individually or uniformly as a group. Individual control is through the array resources, cnFillColors, cnFillPatterns, and cnFillScales while control as a group is through the scalar resources cnFillColor, cnFillPattern, cnFillDotSizeF, and cnFillScaleF. You choose the scalar resources by setting the boolean resources cnMonoFillColor, cnMonoFillPattern, and cnMonoFillScale True; you choose the array resources by setting them False.

Raster fill

ContourPlot performs raster fill by assigning appropriate colors to each cell of a two-dimensional array of equally sized rectangular cells superimposed on the area occupied by the data grid. If cnRasterSmoothingOn is set True, the level (and hence the color) assigned to each cell is determined by interpolating the values of neighboring points in the data grid. If cnRasterSmoothingOn is False (the default), ContourPlot creates a discrete raster plot: any raster cell whose center lies within the rectangular area bounded by lines halfway between each grid point (in data space) is given the color assigned to the level representing the grid point datum.

By default, ContourPlot dynamically tries to achieve an optimal size for the cell array based on the resolution of the workstation, the density of the data grid, the data transformation in effect, and whether smoothing is turned on. However, resources are provided for controlling the density of the raster cell grid. You can either set the cell size explicitly, using the resource cnRasterCellSizeF, or you can adjust the dynamically determined density, using the resource cnRasterSampleFactorF. The cnRasterMinCellSizeF resource sets a lower bound for the size of dynamically sized raster cells and consequently an upper limit on the raster cell density. Its purpose is to prevent the cell array from becoming unreasonably large for high-resolution workstations.

As with area fill, raster fill colors are specified using the cnFillColors resource. The fill pattern and fill scale resources are ignored when in raster fill mode.

Beginning with version 6.2.0, the raster fill mode fully supports transparency and the Transparent color index (-1). Previous versions substituted the Background color whenever Transparent was specified for a color index used in a raster fill context.

Cell fill

ContourPlot performs cell fill by drawing filled polygons whose edges are defined by the borders between adjacent grid cells. If the data grid is defined using cell edges, these boundaries are obtained explicitly from the coordinate arrays. Otherwise, the edges are calculated from the halfway points between the cell centers. Optionally, you may draw lines around the edges by setting the resource cnCellFillEdgeColor to a color other than the default: Transparent. The color of the edges of cells containing missing data values is controlled using a separate resource cnCellFillMissingValEdgeColor.

As with area fill, cell fill colors are specified using the cnFillColors resource. The fill pattern and fill scale resources are ignored when in cell fill mode.

Beginning with version 6.2.0, the cell fill mode can render cells with 3, 4, 5, 6, or more vertices as supplied by various non-structured grids. The vertices of the cells must be explicitly specified using the resources sfXCellBounds and sfYCellBounds.

Labels

Almost two thirds of the ContourPlot object's resources involve attributes of various kinds of labels. This section describes the label types and classifies the label attributes.

ContourPlot supports five label types: line labels, high labels, low labels, an informational label, and a constant field label. The constant field label also has the ability to act as a label indicating that no data have been supplied. Each type has its own set of resources allowing individual control of the particular label type. The resources controlling label attributes have a generally uniform behavior for all label types. The resource names follow a consistent naming scheme for distinguishing the label types and their attributes. There are broadly three categories of label attributes that apply to all labels: those that control the content and format of the text string; those that control the appearance of the text, called font attributes; and those that control the appearance of the label background and perimeter. The informational and constant field labels support a fourth category of label attributes: those that control the location of the label. In addition to these general categories, there are several resources that apply globally to all label types, as well as a few that only apply to a single label type.

To simplify the management of label resources, there are several resources that allow you tie many of the resources of different label types together. cnLowUseHighLabelRes, when set True, causes all low label resources except cnLowLabelString to take on the value of the corresponding high label resource. Similarly, cnHighUseLineLabelRes, when set True, causes all high label resources except cnHighLabelString and cnHighLabelAngleF to take on the value of the corresponding line label resource. And finally, cnConstFUseInfoLabelRes, when set True, causes all constant field label resources except cnConstFLabelString to take on the value of the corresponding informational label resource.

Note that because of constraints imposed by the low level utilities, some attributes of high and low labels are tied together regardless of the setting of cnLowUseHighLabelRes. Also, the line label resources differ because several of them are array resources, allowing individual control of the labels that appear with each contour line.

The following sections discuss each label attribute category as it applies to all label types. The ellipsis marks (...) in the resource names below stand for the names of the label types:

  • Line for line labels
  • High for high labels
  • Low for low labels
  • Info for the informational label
  • ConstF for the constant field label

String content and formatting attributes

These resources control the content and format of all the label types:
cn...Label(s)On
Turns the label on and off. Line, high, and low labels use the plural form. The informational and constant field labels use the singular form.
cn...LabelString(s)
Specifies the text of the label. Line labels use the plural form to indicate an array of strings.
cn...LabelFuncCode
Sets the function code character used for the label text.
cn...LabelFormat
Specifies the format string used for numeric substitutions within the label text.
Since the information in the labels provided by the ContourPlot object is closely tied to the values in the dataset being contoured, there are several resources that apply for all label types to numbers generated from the dataset. Using the resources cnLabelScalingMode and cnLabelScaleValueF, you can choose from a number of methods of scaling the values of the dataset. The point may be to make the label numbers fit within some standard range or simply to make them easier to read. Once you have set these resources, you can get the value of the read-only resource cnLabelScaleFactorF to determine the scale factor used to achieve the desired results. Multiplying the numbers in the labels by the value of cnLabelScaleFactorF gives the actual data values the numbers represent.

You specify the format string for numerical substitutions according to the HLU Floating Point Format Specification scheme. This scheme allows certain aspects of a number's format to be determined dynamically. The ContourPlot object uses this facility to allow you to base the formatting of all labels--in particular the assumed rightmost significant digit--on the dataset element with the maximum absolute value. The resource cnMaxDataValueFormat specifies a format for the dataset element with the maximum absolute value. The value and the format used together determine the specification of each dynamically specified format option for all label types.

The ContourPlot object recognizes a number of special substitution strings that are replaced on output with certain key values related to the dataset and the contour levels. How or whether a particular substitution string is recognized depends on the label type as follows:

$CIU$
The contour interval used (value of cnLevelSpacingF); informational label only.
$CMN$
The minimum contour level (first element of cnLevels); informational label only.
$CMX$
The maximum contour level (last element of cnLevels); informational label only.
$SFU$
The scale factor used (value of cnLabelScaleFactorF); informational label only.
$ZMN$
The minimum data value (value of ScalarField resource sfDataMinV); informational label only.
$ZMX$
The maximum data value (value of ScalarField resource sfDataMaxV); informational label only.
$ZDV$
The current low, high, and constant field value for low, high and constant field labels, respectively.
Note that line labels do not accept any substitution strings; by default the cnLineLabelStrings array is filled with strings representing the value of each contour level.

Font attributes

These resources set font attributes for all the label types:
cn...LabelFontHeightF
Sets the height of the label text.
cn...LabelFont
Sets the font used for the label text.
cn...LabelFontColor(s)
Sets the color of the label text. Line labels use both the plural and singular form for array and scalar versions of the resource.
cn...LabelFontAspectF
Sets the height-to-width ratio of the characters used for the label text.
cn...LabelFontThicknessF
Sets the thickness of the lines used to draw fonts that are stroked rather than filled for the label text.
cn...LabelFontQuality
Sets one of three qualities of fonts to use for the label text.
cn...LabelConstantSpacingF
Determines whether the characters used for label text should have constant spacing, and if so, determines the spacing to use.
cn...LabelAngleF
Sets the angle at which the label text is drawn.
Note that text height and angle for low labels cannot be set differently from high label text height and angle. Currently the resources cnLowLabelFontHeightF and cnLowLabelAngleF are ignored.

If the resource cnMonoLineLabelFontColor is set True, ContourPlot uses the scalar resource cnLineLabelFontColor for all line labels; otherwise it uses the array resource, cnLineLabelFontColors. Also the resource cnLineLabelAngleF is ignored if cnLineLabelPlacementMode is set to Constant.

Backgrounds and perimeter outline attributes

These resources set background and perimeter outline attributes for all the label types:
cn...LabelBackgroundColor
Sets the background color for the area inside the label perimeter.
cn...LabelPerim
Turns the label perimeter outline on and off.
cn...LabelPerimSpaceF
Determines the amount of space between the edges of the label text and the label perimeter.
cn...LabelPerimColor
Sets the color used for the label perimeter line.
cn...LabelPerimThicknessF
Sets the thickness of the label perimeter line.
Note that low label perimeter space and background color cannot be set differently from high label perimeter space and background color. Currently the resources cnLowLabelPerimSpaceF and cnLowLabelBackgroundColor are ignored. Also note that all background and perimeter resources for line labels are ignored when cnLineLabelPlacementMode is set to Constant.

Location and density attributes

You can position the informational and constant field labels using resources that follow the PlotManager Location Control Model. These are:
cn...LabelZone
Sets the overlay zone of the label.
cn...LabelSide
Sets the side on which the label will be located in the plot viewport.
cn...LabelJust
Sets the justification mode used to position the label.
cn...LabelParallelPosF
Sets the offset from the zone origin parallel to the viewport side.
cn...LabelOrthogonalPosF
Sets the offset from the zone origin orthogonal to the viewport side.

There are three ways to position line labels using the resource cnLineLabelPlacementMode. The Constant mode is the most basic: the line label is rendered as a part of the dash pattern. This implies that the label density can be controlled by setting the cnLineDashSegLenF resource, which controls the length of the dash pattern.

For the other two methods, Randomized and Computed, the labels are drawn separately from the lines. You can increase or decrease the density of labels for these modes using cnLineLabelDensityF. For more precise control, you can set a number low level line label positioning parameters using the cnConpackParams resource.

Also you can control in a limited way the location of high and low labels with the resource cnHighLowLabelOverlapMode. There are no native resources for adjusting the high/low label density, but low level control is possible using cnConpackParams.

Special areas and boundaries

There are several boundaries within the viewport of a ContourPlot that separate regions where contours appear from regions where they do not: the boundaries of missing value areas, the data grid boundaries, and the boundaries of regions where the data coordinates map to an out-of-range value. Missing value areas lie in those portions of the data grid whose elements are set to the special signal missing value as set by the ScalarField object's sfMissingValueV resource. You can outline the boundaries of missing value areas and also fill the interior of these areas. On the other hand, you can only draw boundary lines of the data grid and the out-of-range regions.

You control the line attributes of the boundaries with the following resources. The ellipsis marks (...) in the resource names below stand for the names of the boundary types: MissingValue, Grid, or OutOfRange.

cn...BoundPerim
Turns the perimeter line on and off.
cn...BoundPerimThicknessF
Sets the thickness of the line used to draw the perimeter.
cn...BoundPerimDashPattern
Sets the dash pattern of the line used to draw the perimeter.
cn...BoundPerimColor
Sets the color of the line used to draw the perimeter.
The ContourPlot object sets the dash pattern segment length for these special lines with the same resource used for the regular contour lines: cnLineDashSegLenF.

Missing values areas have in addition the resources cnMissingValFillColor, cnMissingValFillPattern, and cnMissingValFillScaleF for controlling the fill attributes of the missing value areas. If the raster mode of contour filling is enabled, only the resource cnMissingValFillColor has any effect.

Contour line rendering control

There are several resources you can use to control the way ContourPlot draws the contour lines. The resource cnSmoothingOn controls whether the contour lines are smoothed (using cubic splines under tension). cnSmoothingTensionF and cnSmoothingDistanceF control parameters of the smoothing algorithm. The resource cnMaxPointDistanceF controls the accuracy with which contour lines near discontinuous points in the mapping are rendered.


Support functions

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

Status notes for Release 4.1

1. The support for irregular transformations is at a transitional stage. Eventually, ContourPlot will be able to perform transformations from irregular coordinates to linear and logarithmic coordinates without using the overlay mechanism. This will eliminate the need for a switch to the index coordinate system.

3. Under certain conditions when part of the data space is outside the viewport, the Computed line label placement mode seems to fail, and the plot appears without any line labels at all. This problem requires further investigation.

4. Large values of cnSmoothingTensionF above 10.0 or so often cause the ContourPlot object to improperly project lines out of the plotter frame. This needs to be examined more closely. Also note that when lines cross, contour fill often 'bleeds' out of its boundaries.

5. Since the ContourPlot object creates the informational label using an Annotation object managed by the PlotManager object, Conpack has no way of knowing the position of the Informational label. Therefore, there is no way to support the option of omitting high and low labels that overlap the informational label. For the time being at least, the type NhlTcnHighLowLabelOverlapMode maps directly to the Conpack internal parameter, 'HLO'. Therefore, numerically speaking, this type effectively has two values for each functionally unique enumerated value.


See also