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ContourPlot (cn) Resources

If cnFillMode is set to CellFill, this resource specifies the color used to draw boundaries around the edges of the data grid cells that contain valid non-missing values. If set to the default value, Transparent, the boundaries do not appear.

You can use a color index value (integer) or a named color (string).

Default: Transparent (-1)

cnCellFillMissingValEdgeColor

If cnFillMode is set to CellFill, this resource specifies the color used to draw boundaries around the edges of the data grid cells that contain missing values. If set to the default value, Transparent, the boundaries do not appear.

You can use a color index value (integer) or a named color (string).

Default: Transparent (-1)

cnConpackParams

This string array resource allows you limited access to a number of parameters belonging to the LLU Conpack package, in order to control certain plot features for which ContourPlot does not yet have native resources. Each element of the array is a string consisting of a Conpack parameter name and its desired value separated by the colon character. Here is an example of its use in a resource file:

*cnConpackParams: (/ RC1:0.05 , RC2:0.1 , RC3:0.05 , \
	PC1:7.0 , PC2:20.0 , PC3:120.0 , PC4:0.01 , PC5:0.05 , PC6:0.05 , \
	PW1:0.0 , PW2:0.0 , PW3:0.0 , PW4:0.0 /)

If set programmatically, each string element would need to quoted as appropriate for the source language. The example given above includes all the parameters that affect the density of line labels when the cnLineLabelPlacementMode is set to Randomized or Computed. The example values should normally result in the appearance of more labels than the default settings. See the Conpack parameter descriptions for more information.

Note that the only Conpack parameters accessible using the cnConpackParams resource are ones that ContourPlot does not set internally and are unlikely to have an interaction with parameters that ContourPlot does set. Here is a categorized list of the Conpack parameters that can be set using cnConpackParams:

Contour hachuring control

High/low label density

Computed placement mode ("Penalty scheme" in Conpack) label density

Randomized placement mode ("Regular scheme" in Conpack) label density

Point interpolation for lines and edges

Note that you cannot get the value of cnConpackParams. Attempts to do so will result in an error.

Default: NULL

cnConstFLabelAngleF

This resource specifies the angle, in degrees, of the constant field label text and its surrounding box.

Default: 0.0

cnConstFLabelBackgroundColor

This resource sets the background color used to fill the box surrounding the constant field label. If you do not want the box to be filled at all, set cnConstFLabelBackgroundColor to Transparent (-1).

You can use a color index value (integer) or a named color (string).

Default: Background (0)

cnConstFLabelConstantSpacingF

Normally when cnLineLabelFontQuality is set to High, the ContourPlot object writes constant field label text with proportional spacing. Setting the cnConstFLabelConstantSpacingF to a value greater than 0.0 overrides this behavior. Instead, the distance from the start of one character to the next is computed by multiplying a single standard character width by the value of cnLineLabelConstantSpacingF. When cnLineLabelConstantSpacingF has a value between 0.0 and 1.0, characters will overlap. A value of 1.0 implies, on average, no space between characters, while values increasing from 1.0 cause the space between characters to grow. This parameter is ignored when cnConstFLabelFontQuality is not High. Values less than 0.0 result in an error and are replaced with the default value.

Default: 0.0

cnConstFLabelFont

This resource of type NhlTFont specifies the font used to render the constant field label.

Default: "pwritx"

cnConstFLabelFontAspectF

This resource determines the shape of the constant field label characters. Values increasing from 1.0 result in thinner characters. Values decreasing from 1.0 make the characters wider. Values less than or equal to 0.0 result in a WARNING message and a restoration of the default value.

Default: 1.3125

cnConstFLabelFontColor

This resource specifies the color to use for drawing constant field label text.

You can use a color index value (integer) or a named color (string).

Default: True

cnConstFLabelFontHeightF

This resource controls the height, in NDC units, of characters used in the text of the constant field label. The character width scales proportionally, unless you also modify the aspect ratio using the cnConstFLabelFontAspectF resource. The constant field label text height scales with changes to the viewport width, unless you explicitly set cnConstFLabelFontHeightF during the same call.

Default: <dynamic> -- 0.012 for a viewport width of 0.6

cnConstFLabelFontQuality

This resource of type NhlTFontQuality determines the quality of the font used to draw the ContourPlot constant field label.

Default: High

cnConstFLabelFontThicknessF

Sets the thickness of the line used to draw constant field label text. The value acts as a multiplier of a (device-dependent) unit thickness. This resource is ignored when the cnConstFLabelFont specifies a filled font (font indexes 21-22, 25-26, 29-30, and 33-37).

Default: 1.0

cnConstFLabelFormat

The cnConstFLabelFormat resource is a string that specifies the printing format for the number generated from a substitution substring in the cnConstFLabelString according to the HLU Floating Point Format Specification scheme. If any of the numerical format parameters have the dynamic attribute on, the corresponding parameter in the cnMaxDataValueFormat resource determines the parameter's value. The default value uses the shorthand notation '*+' to cause all numeric format parameters to be determined dynamically.

Default: "*+^sg"

cnConstFLabelFuncCode

This resource of type NhlTCharacter sets the function code character that the low level utilities will use when parsing the constant field label string.

Default: :

cnConstFLabelJust

This resource of type NhlTJustification, after constraint to an appropriate value based on cnConstFLabelSide, sets the justification of the constant field label annotation with respect to its base location. The PlotManager Location Control Model requires this resource to allow control of the constant field label consistent with other annotations.

Default: CenterCenter

cnConstFLabelOn

The ContourPlot object draws a constant field label annotation only when cnConstFLabelOn is set True and the ScalarField data are determined to have a single constant value within the limits of the available precision or when no ScalarField data are supplied.

Default: True

cnConstFLabelOrthogonalPosF

cnConstFLabelOrthogonalPosF sets the coordinate of the base location of the constant field label annotation orthogonal to the current cnConstFLabelSide and directed away from the center of the viewport. The PlotManager Location Control Model requires this resource to allow control of the constant field label consistent with other annotations.

Default: 0.0

cnConstFLabelParallelPosF

cnConstFLabelParallelPosF specifies the coordinate of the base location of the constant field label annotation parallel to the current cnConstFLabelSide and directed toward increasing NDC values. The PlotManager Location Control Model requires this resource to allow control of the constant field label consistent with other annotations.

Default: 0.0

cnConstFLabelPerimColor

This resource sets the color to use for drawing the perimeter of the constant field label box.

You can use a color index value (integer) or a named color (string).

Default: Foreground (1)

cnConstFLabelPerimOn

cnConstFLabelPerimOn is a boolean resource that determines whether ContourPlot will draw an outline around the perimeter of the box surrounding the contour constant field label. If set False, no outline will be drawn.

Default: True

cnConstFLabelPerimSpaceF

cnConstFLabelPerimSpaceF determines the spacing or margin between the text of the constant field label and the edge of the constant field label box as a fraction of the current label text height.

Default: 0.33

cnConstFLabelPerimThicknessF

This resource determines the thickness of the perimeter line around the constant field label box. The value acts as a multiplier of a (device-dependent) unit thickness.

Default: 1.0

cnConstFLabelSide

This resource of type NhlTPosition determines where to place the constant field annotation in relation to the sides of the plot object. The PlotManager Location Control Model requires this resource to allow control of the constant field label consistent with other annotations. Its value determines a coordinate system origin and the direction of the positional resources, cnConstFLabelParallelPosF and cnConstFLabelOrthogonalPosF. It also constrains the value of the cnConstFLabelJust appropriately. There are four settings, which behave as follows, unless cnConstFLabelZone is set to one of the special zones (0 or 1):

Top: PlotManager locates the constant field label annotation relative to a line that parallels the top viewport boundary. cnConstFLabelOrthogonalPosF increases in the direction of increasing NDC Y-Axis values and is constrained to positive values. cnConstFLabelParallelPosF increases in the direction of increasing NDC X-Axis values. cnConstFLabelJust is constrained to BottomRight, BottomCenter, or BottomLeft.
Bottom: PlotManager locates the constant field label annotation relative to a line that parallels the bottom viewport boundary. cnConstFLabelOrthogonalPosF increases in the direction of decreasing NDC Y-Axis values and is constrained to positive values. cnConstFLabelParallelPosF increases in the direction of increasing NDC X-Axis values. cnConstFLabelJust is constrained to TopRight, TopCenter, or TopLeft.
Right: PlotManager locates the constant field label annotation relative to a line that parallels the right viewport boundary. cnConstFLabelOrthogonalPosF increases in the direction of increasing NDC X-Axis values and is constrained to positive values. cnConstFLabelParallelPosF increases in the direction of increasing NDC Y-Axis values. cnConstFLabelJust is constrained to TopLeft, CenterLeft, or BottomLeft.
Left: PlotManager locates the constant field label annotation relative to a line that parallels the left viewport boundary. cnConstFLabelOrthogonalPosF increases in the direction of decreasing NDC X-Axis values and is constrained to positive values. cnConstFLabelParallelPosF increases in the direction of increasing NDC Y-Axis values. cnConstFLabelJust is constrained to TopRight, CenterRight, or BottomRight.

If cnConstFLabelZone is set to 0, the PlotManager locates the constant field label annotation relative to the viewport center. If cnConstFLabelZone is 1, the direction of the cnConstFLabelOrthogonalPosF is opposite to the specification given above. Also if the cnConstFLabelZone is either 0 or 1, cnConstFLabelJust is not constrained, and cnConstFLabelOrthogonalPosF may take on negative values.

Default: Bottom

cnConstFLabelString

Specifies the string to use when drawing a constant field label. The string may contain function codes and/or substitution substrings. ContourPlot will replace the substring $ZDV$ with a number representing the constant field value. cnConstFLabelFormat determines the format of the number; its value will be scaled based on the value of cnLabelScaleFactorF.

Default: "CONSTANT FIELD - VALUE IS $ZDV$"

cnConstFLabelTextDirection

This resource of type NhlTTextDirection specifies the direction of the text in the constant field label. The choices are:

Down: Each character is placed below the previous character in the text string.
Across: Each character is placed to the right of the previous character in the text string.

These directions apply before rotation due to cnConstFLabelAngleF.

Default: Across

cnConstFLabelZone

ContourPlot implements the constant field label as an embedded annotation. cnConstFLabelZone specifies the PlotManager zone assigned to the constant field annotation. The PlotManager Location Control Model requires this resource to allow control of the constant field label consistent with other annotations. If cnConstFLabelZone is set to 0, the positional origin is the center of the plot viewport; otherwise it is on or outside one of the sides of the viewport.

If you create a ContourPlot object without an active PlotManager by setting tfPlotManagerOn False, then ContourPlot manages the constant field annotation by itself. In this case, the cnConstFLabelZone resource is not as meaningful.

Default: 0

cnConstFUseInfoLabelRes

If the boolean resource cnConstFUseInfoLabelRes is set True, all the resources applying to the constant field, except for cnConstFLabelString, take their value from the corresponding informational label resources.

Default: False

cnExplicitLabelBarLabelsOn

This boolean resource allows you control the labels that appear in the ContourPlot LabelBar explicitly. When set True, ContourPlot does not block the LabelBar resources lbLabelStrings and lbLabelAlignment. Therefore you can directly control both the contents of the LabelBar's label strings and their alignment with respect to the label boxes. When cnExplicitLabelBarLabelsOn is set False, ContourPlot sets both of these resources based on the current contour line labels and the value of the resource cnLabelBarEndStyle (as of version 5.0.0 or later) or (prior to version 5.0.0 or if cnLabelBarEndStyle is not set) cnLabelBarEndLabelsOn. If you set this resource True but do not set the lbLabelStrings array resource, ContourPlot will set it for you one time. This allows you to get an initial set of strings as a starting point for any customized tweaking you want to perform.

Default: False

cnExplicitLegendLabelsOn

This boolean resource allows you control the labels that appear in the ContourPlot Legend explicitly. When set True, ContourPlot does not block the Legend resource lgLabelStrings. Therefore you can directly control the content of the Legend's label strings. When cnExplicitLegendLabelsOn is set False, ContourPlot sets lgLabelStrings based on the value of the current contour line labels. If you set this resource True but do not set the lgLabelStrings array resource, ContourPlot will set it for you one time. This allows you to get an initial set of strings as a starting point for any customized tweaking you want to perform.

Default: False

cnExplicitLineLabelsOn

This boolean resource controls the way ContourPlot handles the cnLineLabelStrings array resource. When set True, ContourPlot will not modify explicitly set values of the line label strings. When cnExplicitLineLabelsOn is set False, ContourPlot ignores values of cnLineLabelStrings set by the user.

Default: False

cnFillBackgroundColor

This resource of type NhlTColorIndex or a named color (string) sets the background color used for ContourPlot fill patterns. It only has an effect for fill patterns that are neither SolidFill nor HollowFill. By default, this resource is set to Transparent, resulting in the underlying background appearing in the spaces between the elements of the fill pattern. If set to any other valid color index, the specified color will solidly fill all spaces between the fill pattern elements.

Default: Transparent (-1)

cnFillColor

When cnMonoFillColor is set True, this resource of type NhlTColorIndex or a named color (string) sets a uniform fill color for all contour fill areas.

Default: Foreground (1)

cnFillColors

If cnMonoFillColor is False, each element of this array of type NhlTColorIndexGenArray or named color (string) specifies the color of a contour fill area. Note that there is always one more fill area than there are contour levels. The first element of cnFillColors specifies the fill pattern for any region containing a data value less than the value of cnMinLevelValF, while the highest currently used element of cnFillColors specifies the fill pattern for regions containing data values greater than the value of cnMaxLevelValF. Otherwise cnFillColors works in a fashion similar to cnLineColors. If the array is not set explicitly, it will default to a set of color indexes sequentially incremented beginning with color index 1 (NhlFOREGROUND). If the array currently contains fewer elements than cnLevelCount+1, more elements will be added to the array and given values according to the default color assignment scheme; existing elements with valid color index values will not be modified.

Default: <dynamic>

cnFillDotSizeF

This resource sets a uniform dot size, in NDC units, for the stipple dot fill pattern. The default value of 0.0 causes the dots to be drawn as before, using a workstation dependent minimum dot size. A caveat is that individual dots are not clipped around the edges of fill areas; this becomes more noticeable as the dot size increases.

Default: 0.0

cnFillDrawOrder

This resource of type NhlTDrawOrder determines when areas of the contour plot are filled relative to the drawing of other elements of the plot. There are three choices:

PreDraw: Fill contour areas before the standard draw phase; fill areas will be overlaid by any subsequently drawn elements.
Draw: Fill contour areas during the standard draw phase; the fill will overlay any elements drawn during the predraw phase, but will underlie elements drawn during the postdraw phase.
PostDraw: Fill contour areas after the standard draw; the fill will overlay any elements drawn during the predraw and draw phases.

You must manipulate this resource in order to mask contours within the context of an Overlay of multiple plot objects.

Default: Draw

cnFillMode

This resource of type NhlTcnFillMode determines how ContourPlot performs fill when cnFillOn is set True. There are three choices:

AreaFill

The area between contour levels is decomposed into polygons. The polygons are then filled based on the applicable fill color, fill pattern, the scale factor assigned to the pattern, and, if stipple fill (fill pattern 17) is specified, the size of the stippling dots.

The following resources can be used to control fill features when cnFillMode is set to AreaFill:

Currently when using AreaFill mode, and cnScalarFieldData is specified using a MeshScalarField object, and the ContourPlot is overlaid on certain map projections, the edges of the plot may have a ragged appearance and not completely fill the projected data boundaries.

RasterFill

ContourPlot generates a representation of the data by individually assigning colors to the elements of a two-dimensional array of rectangular cells (a raster array) superimposed on an area bounding the data grid. With raster mode, only solid fill is possible, and therefore resources related to fill pattern specification have no effect. The color of each cell is determined based on the fill color assigned to the data value at the cell's location. If cnRasterSmoothingOn is set True, the data value for each raster cell is interpolated from the values of data grid cells in the neighborhood. Otherwise, each raster cell is assigned the color associated with the grid cell within which the greatest proportion of its area lies. Cells of a raster fill plot cannot be transparent. If a fill index of Transparent is set for any cell of a raster fill plot, the Background color will be used instead.

The following resources can be used to control fill features when cnFillMode is set to RasterFill:

Currently when using RasterFill mode, and trGridType is set to TriangularMesh, and the ContourPlot is overlaid on certain map projections, the edges of the plot may have a ragged appearance and not completely fill the projected data boundaries.

CellFill

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, the cell boundaries are obtained explicitly from the coordinate arrays. Otherwise, the edges are assumed to pass through the halfway points in data grid space between the cell centers. Optionally, you may draw lines around the edges using the cell fill edge resources. As with raster fill, pattern fill is not supported. Unlike raster fill, however, the cells may be transparent.

The following resources can be used to control fill features when cnFillMode is set to CellFill:

Currently the CellFill mode is not available when cnScalarFieldData is specified using a MeshScalarField object.

Default: AreaFill

cnFillOn

This boolean resource controls whether the areas between contour levels are filled with a solid color and/or, if the fill method permits it, a fill pattern. You can choose between three fill methods by setting the resource cnFillMode.

Default: False

cnFillPattern

When cnMonoFillPattern is set True, this resource of type NhlTFillIndex sets a uniform pattern for all contour fill areas.

Default: SolidFill

cnFillPatterns

If cnMonoFillPattern is False, each element of this array of type NhlTFillIndexGenArray specifies the fill pattern used for a contour fill area. Note that there is always one more fill area than there are contour levels. The first element of cnFillPatterns specifies the fill pattern for any region containing a data value less than the value of cnMinLevelValF, while the highest currently used element of cnFillPatterns specifies the fill pattern for regions containing data values greater than the value of cnMaxLevelValF. If the array is not set explicitly, the ContourPlot object will assign sequential fill pattern indexes (starting with fill index 1--not "SolidFill", which is fill index 0) to each array element up to the maximum number of existing fill patterns. Thereafter it will repeat the sequence using modular arithmetic. If the array currently contains fewer elements than cnLevelCount+1, more elements will be added to the array and given values according to the same assignment scheme; existing elements with valid fill pattern index values will not be modified.

Default: <dynamic>

cnFillScaleF

When cnMonoFillScale is True, this resource sets a uniform scaling value for all contour fill patterns.

Default: 1.0

cnFillScales

When cnMonoFillScale is False, the cnFillScales array resource allows individual control of the scaling of the pattern used for each contour fill area. It has no effect for solid fill (fill pattern "SolidFill", index 0). Values greater than 1.0 make the pattern spacing bigger than the default spacing, resulting in a fill that appears less dense. Values less than 1.0 have the opposite effect. Values less than or equal to 0.0 are invalid, generate a warning message, and are reset to the default value, 1.0.

Note that there is always one more fill area than there are contour levels. If the array is not set explicitly, the ContourPlot object will assign the value 1.0 to all elements of the array. If the array currently contains fewer elements than cnLevelCount+1, more elements will be added to the array and given the same default value of 1.0; existing elements with valid fill scale index values will not be modified.

Default: 1.0 for all elements

cnFixFillBleed

When cnFillOn is set True, but cnRasterModeOn is set False, ContourPlot performs area fill. Occasionally, due to limitations of the area rendering algorithm, this mode of fill fails and colors "bleed" out into areas they do not belong. If you have this kind of problem with your plot, it will probably be fixed if you set the resource cnFixFillBleed to True.

However, there are certain kinds of plots that have problems when cnFixFillBleed is set True, and so far there is no clear algorithm for distinguishing these. Therefore, the corrections that are applied as a result of setting cnFixFillBleed cannot be yet be unconditionally coded into ContourPlot. Eventually, it is hoped that the need for this resource will be eliminated.

Default: False

cnGridBoundPerimColor

This resource sets the color to use for drawing the perimeter line around the grid boundary.

You can use a color index value (integer) or a named color (string).

Default: Foreground (1)

cnGridBoundPerimDashPattern

This resource sets the HLU index of a dash pattern used to render the perimeter line around the grid boundary.

Default: 0

cnGridBoundPerimOn

If set True, this boolean resource specifies that a perimeter line be drawn around the grid boundary (extent of the ScalarField data) in the ContourPlot plot.

Default: False

cnGridBoundPerimThicknessF

This resource determines the thickness of the perimeter line around the grid boundary. The value acts as a multiplier of a (device-dependent) unit thickness.

Default: 1.0

cnHighLabelAngleF

This resource specifies the angle, in degrees, of high label text and its surrounding box.

Default: 0.0

cnHighLabelBackgroundColor

This resource sets the background color used to fill the box surrounding each high label. If you do not want the box to be filled at all, set cnHighLabelBackgroundColor to Transparent (-1).

Default: Background (0)

cnHighLabelConstantSpacingF

Normally when cnLineLabelFontQuality is set to High, the ContourPlot object writes line label text with proportional spacing. Setting the cnLineLabelConstantSpacingF to a value greater than 0.0 overrides this behavior. Instead, the distance from the start of one character to the next is computed by multiplying a single standard character width by the value of cnLineLabelConstantSpacingF. When cnLineLabelConstantSpacingF has a value between 0.0 and 1.0, characters will overlap. A value of 1.0 implies, on average, no space between characters, while values increasing from 1.0 cause the space between characters to grow. This parameter is ignored when cnLineLabelFontQuality is not High. Values less than 0.0 result in an error and are replaced with the default value.

Default: 0.0

cnHighLabelCount

Each time a ContourPlot is drawn, the read-only resource cnHighLabelCount is updated with the number of high labels actually rendered in the plot. Until the plot is drawn for the first time cnHighLabelCount has the value 0;

Default: 0

cnHighLabelFont

This resource of type NhlTFont specifies the font used to render high labels.

Default: "pwritx"

cnHighLabelFontAspectF

This resource determines the shape of the high label characters. Values increasing from 1.0 result in thinner characters. Values decreasing from 1.0 make the characters wider. Values less than or equal to 0.0 result in a WARNING message and a restoration of the default value.

Default: 1.3125

cnHighLabelFontColor

This resource specifies the color to use for the high label text. If cnHighUseLineLabelRes is True, this resource takes its value from the first element of the cnLineLabelFontColors array.

You can use a color index value (integer) or a named color (string).

Default: True

cnHighLabelFontHeightF

This resource controls the height, in NDC units, of characters used in the text of high labels. The character width scales proportionally, unless you also modify the aspect ratio using the cnHighLabelFontAspectF resource. The high label text height scales with changes to the viewport width, unless you explicitly set cnHighLabelFontHeightF during the same call.

Default: <dynamic> -- 0.012 for a viewport width of 0.6

cnHighLabelFontQuality

This resource of type NhlTFontQuality determines the quality of the font used to draw ContourPlot high labels.

Default: High

cnHighLabelFontThicknessF

Sets the thickness of the line used to draw high label text. The value acts as a multiplier of a (device-dependent) unit thickness. This resource is ignored when the cnHighLabelFont specifies a filled font (font indexes 21-22, 25-26, 29-30, and 33-37).

Default: 1.0

cnHighLabelFormat

The cnHighLabelFormat resource is a string that specifies the printing format for the numeric portion of high labels according to the HLU Floating Point Format Specification scheme. If any of the numerical format parameters have the dynamic attribute on, the corresponding parameter in the cnMaxDataValueFormat resource determines the parameter's value. The default value uses the shorthand notation '*+' to cause all numeric format parameters to be determined dynamically.

Default: "*+^sg"

cnHighLabelFuncCode

This resource of type NhlTCharacter sets the function code character that the low level utilities will use when parsing the high label string.

Default: :

cnHighLabelPerimColor

This resource sets the HLU color index used to draw the perimeter of the high label box.

Default: Foreground (1)

cnHighLabelPerimOn

cnHighLabelPerimOn is a boolean resource that determines whether ContourPlot will draw an outline around the perimeter of the box surrounding contour high labels. If set False, no outline will be drawn.

Default: True

cnHighLabelPerimSpaceF

cnHighLabelPerimSpaceF determines the spacing or margin between the text of the high label and the edge of the high label box as a fraction of the current high label text height.

Default: 0.33

cnHighLabelPerimThicknessF

This resource determines the thickness of the perimeter line around the high label box. The value acts as a multiplier of a (device-dependent) unit thickness.

Default: 1.0

cnHighLabelString

Specifies the string to use when drawing high labels. The string may contain function codes and/or substitution substrings. ContourPlot will replace the substring "$ZDV$" with a number representing the value at the point where the label is to appear. cnHighLabelFormat determines the format of the number and cnLabelScaleFactorF determines the scaling of the actual data value.

Default: "H:B:$ZDV$:E:"

cnHighLabelsOn

If this boolean resource is set True, ContourPlot places labels at regions representing local maximums in the dataset.

Default: False

cnHighLowLabelOverlapMode

cnHighLowLabelOverlapMode is a resource of type NhlTcnHighLowLabelOverlapMode. It controls how high and low labels are allowed to overlap other elements of the ContourPlot plot and has six possible settings:

IgnoreOverlap: The ContourPlot object does nothing to prevent high and low labels from overlapping other elements of the ContourPlot plot.
OmitOverHL: The ContourPlot object omits high and low labels that would overlap previously determined high or low labels.
OmitOverVP: The ContourPlot object omits high and low labels that would overlap the edge of the viewport.
OmitOverVPAndHL: The ContourPlot object omits high and low labels that would overlap the edge of the viewport or previously determined high or low labels.
AdjustVP: The ContourPlot object adjusts the position of high and low labels that would overlap the edge of the viewport enough to eliminate the problem.
AdjustVPOmitOverHL: The ContourPlot object adjusts the position of high and low labels that would overlap the edge of the viewport enough to eliminate the problem and omits high and low labels that would overlap previously determined high or low labels.

V4.1 Status Note 5

Default: IgnoreOverlap

cnHighUseLineLabelRes

If the boolean resource cnHighUseLineLabelRes is set True, all resources applying to high labels, except for cnHighLabelString and cnHighLabelAngleF, take their value from the corresponding line label resources.

Default: False

cnInfoLabelAngleF

This resource specifies the angle, in degrees, of the informational label text and its surrounding box.

Default: 0.0

cnInfoLabelBackgroundColor

This resource sets the background color used to fill the box surrounding the informational label. If you do not want the box to be filled at all, set cnInfoLabelBackgroundColor to Transparent (-1).

You can use a color index value (integer) or a named color (string).

Default: Background (0)

cnInfoLabelConstantSpacingF

Normally when cnLineLabelFontQuality is set to High, the ContourPlot object writes informational label text with proportional spacing. Setting the cnInfoLabelConstantSpacingF to a value greater than 0.0 overrides this behavior. Instead, the distance from the start of one character to the next is computed by multiplying a single standard character width by the value of cnLineLabelConstantSpacingF. When cnLineLabelConstantSpacingF has a value between 0.0 and 1.0, characters will overlap. A value of 1.0 implies, on average, no space between characters, while values increasing from 1.0 cause the space between characters to grow. This parameter is ignored when cnInfoLabelFontQuality is not High. Values less than 0.0 result in an error and are replaced with the default value.

Default: 0.0

cnInfoLabelFont

This resource of type NhlTFont specifies the font used to render the informational label.

Default: "pwritx"

cnInfoLabelFontAspectF

This resource determines the shape of the informational label characters. Values increasing from 1.0 result in thinner characters. Values decreasing from 1.0 make the characters wider. Values less than or equal to 0.0 result in a WARNING message and a restoration of the default value.

Default: 1.3125

cnInfoLabelFontColor

This resource specifies the color to use for the informational label text.

You can use a color index value (integer) or a named color (string).

Default: Foreground (1)

cnInfoLabelFontHeightF

This resource controls the height, in NDC units, of characters used in the text of the informational label. The character width scales proportionally, unless you also modify the aspect ratio using the cnInfoLabelFontAspectF resource. The info label text height scales with changes to the viewport width, unless you explicitly set cnInfoLabelFontHeightF during the same call.

Default: <dynamic> -- 0.012 for a viewport width of 0.6

cnInfoLabelFontQuality

This resource of type NhlTFontQuality determines the quality of the font used to draw the ContourPlot informational label.

Default: High

cnInfoLabelFontThicknessF

Sets the thickness of the line used to draw informational label text. The value acts as a multiplier of a (device-dependent) unit thickness. This resource is ignored when the cnInfoLabelFont specifies a filled font (font indexes 21-22, 25-26, 29-30, and 33-37).

Default: 1.0

cnInfoLabelFormat

The cnInfoLabelFormat resource is a string that specifies the printing format for the numbers generated from substitution substrings in cnInfoLabelString according to the HLU Floating Point Format Specification scheme. If any of the numerical format parameters have the dynamic attribute on, the corresponding parameter in the cnMaxDataValueFormat resource determines the parameter's value. The default value uses the shorthand notation '*+' to cause all numeric format parameters to be determined dynamically.

Default: "*+^sg"

cnInfoLabelFuncCode

This resource of type NhlTCharacter sets the function code character that the low level utilities will use when parsing the informational label string.

Default: :

cnInfoLabelJust

This resource of type NhlTJustification, after constraint to an appropriate value based on cnInfoLabelSide, sets the justification of the informational label annotation with respect to its base location. The PlotManager Location Control Model requires this resource to allow control of the informational label consistent with other annotations.

Default: TopRight

cnInfoLabelOn

If this boolean resource is set False, ContourPlot will not draw an informational label.

Default: True (False for gsn_csm contour routines when contour fill is turned on.)

cnInfoLabelOrthogonalPosF

cnInfoLabelOrthogonalPosF sets the coordinate of the base location of the informational label annotation orthogonal to the current cnInfoLabelSide and directed away from the center of the viewport. The PlotManager Location Control Model requires this resource to allow control of the informational label consistent with other annotations.

Default: 0.02

cnInfoLabelParallelPosF

cnInfoLabelParallelPosF specifies the coordinate of the base location of the informational label annotation parallel to the current cnInfoLabelSide and directed toward increasing NDC values. The PlotManager Location Control Model requires this resource to allow control of the informational label consistent with other annotations.

Default: 1.0

cnInfoLabelPerimColor

This resource sets the color to use for drawing the perimeter of the informational label box.

You can use a color index value (integer) or a named color (string).

Default: Foreground (1)

cnInfoLabelPerimOn

cnInfoLabelPerimOn is a boolean resource that determines whether ContourPlot will draw an outline around the perimeter of the box surrounding a contour informational label. If set False, no outline will be drawn.

Default: True

cnInfoLabelPerimSpaceF

cnInfoLabelPerimSpaceF determines the spacing or margin between the text of the informational label and the edge of the informational label box as a fraction of the current label text height.

Default: 0.33

cnInfoLabelPerimThicknessF

This resource determines the thickness of the perimeter line around the informational label box. The value acts as a multiplier of a (device-dependent) unit thickness.

cnInfoLabelSide

This resource of type NhlTPosition determines where to place the informational annotation in relation to the sides of the plot object. The PlotManager Location Control Model requires this resource to allow control of the informational label consistent with other annotations. Its value determines a coordinate system origin and the direction of the positional resources, cnInfoLabelParallelPosF and cnInfoLabelOrthogonalPosF. It also constrains the value of cnInfoLabelJust appropriately. There are four settings that behave as follows, unless cnInfoLabelZone is set to one of the special zones (0 or 1):

Top: PlotManager locates the informational label annotation relative to a line paralleling the top viewport boundary. cnInfoLabelOrthogonalPosF increases in the direction of increasing NDC Y-Axis values and is constrained to positive values. cnInfoLabelParallelPosF increases in the direction of increasing NDC X-Axis values. cnInfoLabelJust is constrained to BottomRight, BottomCenter, or BottomLeft.
Bottom: PlotManager locates the informational label annotation relative to a line that parallels the bottom viewport boundary. cnInfoLabelOrthogonalPosF increases in the direction of decreasing NDC Y-Axis values and is constrained to positive values. cnInfoLabelParallelPosF increases in the direction of increasing NDC X-Axis values. cnInfoLabelJust is constrained to TopRight, TopCenter, or TopLeft.
Right: PlotManager locates the informational label annotation relative to a line that parallels the right viewport boundary. cnInfoLabelOrthogonalPosF increases in the direction of increasing NDC X-Axis values and is constrained to positive values. cnInfoLabelParallelPosF increases in the direction of increasing NDC Y-Axis values. cnInfoLabelJust is constrained to TopLeft, CenterLeft, or BottomLeft.
Left: PlotManager locates the informational label annotation relative to a line that parallels the left viewport boundary. cnInfoLabelOrthogonalPosF increases in the direction of decreasing NDC X-Axis values and is constrained to positive values. cnInfoLabelParallelPosF increases in the direction of increasing NDC Y-Axis values. cnInfoLabelJust is constrained to TopRight, CenterRight, or BottomRight.

If cnInfoLabelZone is set to 0, the PlotManager locates the informational label annotation relative to the viewport center. If cnInfoLabelZone is 1, the direction of the cnInfoLabelOrthogonalPosF is opposite to the specification given above. Also if the cnInfoLabelZone is either 0 or 1, cnInfoLabelJust is not constrained, and cnInfoLabelOrthogonalPosF may take on negative values.

Default: Bottom

cnInfoLabelString

Specifies the string to use when drawing an informational label. The string may contain function codes and/or substitution substrings. ContourPlot will replace the following substrings with numeric values:

$CIU$: The contour interval used (value of cnLevelSpacingF)
$CMN$: The minimum contour level (first element of cnLevels)
$CMX$: The maximum contour level
$SFU$: The scale factor used (value of cnLabelScaleFactorF)
$ZMN$: The minimum data value
$ZMX$: The maximum data value

cnInfoLabelFormat determines the format of each number and except for the number generated from $SFU$, all values are scaled based on the value of cnLabelScaleFactorF.

Default: "CONTOUR FROM $CMN$ TO $CMX$ BY $CIU$"

cnInfoLabelTextDirection

This resource of type NhlTTextDirection specifies the direction of the text in the informational label. The choices are:

Down: Each character is placed below the previous character in the text string.
Across: Each character is placed to the right of the previous character in the text string.

These directions apply before any rotation due to cnInfoLabelAngleF is applied to the informational label.

Default: Across

cnInfoLabelZone

ContourPlot implements the informational label as an embedded annotation. cnInfoLabelZone specifies the PlotManager zone assigned to the informational annotation. The PlotManager Location Control Model requires this resource to allow control of the informational label consistent with other annotations. If cnInfoLabelZone is set to 0, the positional origin is the center of the plot viewport; otherwise it is on or outside one of the sides of the viewport.

If you create a ContourPlot object without an active PlotManager by setting tfPlotManagerOn False, then ContourPlot manages the informational annotation by itself. In this case, the cnInfoLabelZone resource is not as meaningful.

Default: 3

cnLabelBarEndLabelsOn

When this boolean resource is set True and cnExplicitLabelBarLabelsOn is False, ContourPlot creates labels for the two ends of the LabelBar. The label at one end will be a string representation of the minimum value in the dataset, and at the other end will be a string representation of the maximum value in the dataset. Both strings will be formatted according to the format specification in effect for the other labels provided by ContourPlot to the LabelBar.

As of version 5.0.0 or later this resource is deprecated and is overridden by cnLabelBarEndStyle when both are set at the same time.

Default: False

cnLabelBarEndStyle

Available in version 5.0.0 or later.

This enumerated resource of type NhlTLabelBarEndStyle allows you to select from among three styles for the ends of the ContourPlot LabelBar:

IncludeOuterBoxes: The two end boxes represent the fill color and/or patterns used for areas of the plot where the data is below the minimum contour level or above the maximum contour level. The first and last labels, representing the minimum and maximum contour levels, are aligned with the interior boundaries of the outer boxes.
IncludeMinMaxLabels: The two end boxes represent the fill color and/or patterns used for areas of the plot where the data is below the minimum contour level or above the maximum contour level. The first and last labels, representing the minimum and maximum values in the field, are aligned with the exterior boundaries of the outer boxes. However, if the minimum and/or maximum field values fall within the range specified by the minimum and maximum contour levels, one or both of these labels will be set to an empty string.
ExcludeOuterBoxes: Only boxes representing fill colors and/or patterns between the minimum and maximum contour levels appear in the LabelBar. The first and last labels, representing the minimum and maximum contour levels, are aligned with the exterior boundaries of what have now become the outer boxes of the LabelBar. This setting is useful in cases where there exist maximum and minimum values that by the nature of the quantity always bound the data, e.g. probability or per cent cloud cover.

As of version 5.0.0 or later this resource overrides the now deprecated cnLabelBarEndLabelsOn when both are set at the same time.

Default: IncludeOuterBoxes

cnLabelDrawOrder

This resource of type NhlTDrawOrder determines when contour plot labels are drawn relative to the drawing of other elements of the plot. There are three choices:

PreDraw: Draw contour labels before the standard draw phase; the labels will be overlaid by any subsequently drawn elements.
Draw: Draw contour labels during the standard draw phase; the labels will overlay any elements drawn during the predraw phase as well as fill and contour lines drawn during the standard draw phase, but will underlie elements drawn during the postdraw phase.
PostDraw: Draw contour labels after the standard draw; the labels will overlay any elements drawn during the predraw and draw phases as well as lines and fill drawn during the postdraw phase.

Default: Draw

cnLabelMasking

This resource controls whether ContourPlot lines and fill are masked in the areas where ContourPlot labels are to appear. When working with raster type devices, it is seldom necessary to mask for labels, since they can be made to solidly overlay the areas where they appear. Also there is a noticeable performance penalty when labels are masked, so the use of this option is discouraged unless it is necessary.

Default: False

cnLabelScaleFactorF

cnLabelScaleFactorF is a read-only resource that contains the current scale factor that applies to ContourPlot object labels. Multiplying the numbers in the labels by the value of cnLabelScaleFactorF gives the actual data values the numbers represent. The ContourPlot object calculates its value based on the data value with the maximum absolute value, the current mode of the enumerated resource, cnLabelScalingMode, and perhaps the value of cnLabelScaleValueF. Its value may also be influenced by the number of significant digits specified by the format specification resource, cnMaxDataValueFormat. You may output the value of this resource in the informational label using the the substitution string "$SFU$".

Default: <dynamic>

cnLabelScaleValueF

The interpretation of cnLabelScaleValueF depends on the value of the enumerated resource cnLabelScalingMode. When cnLabelScalingMode is set to ScaleFactor, data values are divided by the value of cnLabelScaleValueF to obtain the numbers appearing in ContourPlot object labels. If cnLabelScalingMode is set to ConfineToRange, the cnLabelScaleValueF represents an exclusive upper bound for the numbers used to represent the data values. For other values of cnLabelScalingMode, the cnLabelScaleValueF resource is ignored.

Default: 1.0

cnLabelScalingMode

This resource of type NhlTScalingMode determines how to scale the numbers representing scalar field data values in the ContourPlot object's labels. cnLabelScalingMode applies to numbers that represent data values in line labels, high and low labels, the informational label, and the constant field label. There are five choices:

ScaleFactor: The ContourPlot object divides the data value by the value of cnLabelScaleValueF to obtain the number that appears in the label.
ConfineToRange: The ContourPlot object uses cnLabelScaleValueF as an exclusive upper bound. A scale factor is selected such that the number used to represent the data value with the maximum absolute value will be less than cnLabelScaleValueF, but greater than or equal to cnLabelScaleValueF divided by 10.0. As an example, setting cnLabelScaleValueF to 100.0 would result in a scaled number in the range 10.0 to 99.999....
TrimZeros: The ContourPlot object selects a scale factor such that the number representing the data value with the maximum absolute value will have the fewest possible extra zeros. If the maximum absolute value were 245000, for instance, it would scale to 245. If it were 0.000245, it would scale to 0.245. (The zero conventionally placed before the decimal point of a number less than 1.0 is not considered.)
MaxSigDigitsLeft: The ContourPlot object selects a scale factor such that the number representing the data value with the maximum absolute value will have its rightmost significant digit directly to the left of the decimal point. The number of significant digits is determined by the format string resource, cnMaxDataValueFormat.
AllIntegers: The ContourPlot object selects a scale factor such that the numbers representing labeled contour levels (as determined by examination of the values of the cnLevelFlags array) can be rendered as integers.

In each case, the scale factor selected is placed into the read-only resource, cnLabelScaleFactorF. Note that the label value multiplied by the scale factor returns the actual data value represented.

Default: ScaleFactor

cnLegendLevelFlags

This array resource of type NhlTcnLevelUseModeGenArray allows you to control which of the lines representing contour levels are to appear in the ContourPlot Legend. You can also control whether the lines that do appear are to get a line label. Although the type allows for four choices, this resource supports only three of them:

NoLine: Do not draw a line representing this contour level in the Legend.
LineOnly: Draw a line representing this contour level, but no label in the Legend.
LabelOnly: Currently, if an element is set to this value, it is treated the same as if it were set to NoLine.
LineAndLabel: Draw a line representing this contour level along with a line label in the Legend.

If you set this resource with an array containing fewer elements than the current number of contour levels, additional elements are supplied and set to the value NoLine.

Default: NULL

cnLevelCount

A read-only resource set to the actual number of levels chosen during the level selection process.

Default: <dynamic>

cnLevelFlag

When cnMonoLevelFlag is set True, this resource of type NhlTcnLevelUseMode sets the rendering of all contour levels to one of four possible values:

NoLine: No lines or labels appear.
LineOnly: Lines but no labels appear.
LabelOnly: Labels but no lines appear.
LineAndLabel: Both lines and labels appear.

Note that the resources cnLinesOn and cnLineLabelsOn must both be set True to enable all possible settings of cnLevelFlag.

Default: LineOnly

cnLevelFlags

When cnMonoLevelFlag is False, cnLevelFlags is an array of type NhlTcnLevelUseModeGenArray that allows you individual control over whether a line and/or a line label is to appear at each contour level. It has no effect on contour fill. There are four choices:

NoLine: No lines or labels appear at the contour level.
LineOnly: Lines but no labels appear at the contour level.
LabelOnly: Labels but no lines appear at the contour level.
LineAndLabel: Both lines and labels appear at the contour level.

Note that cnLinesOn and cnLineLabelsOn exert underlying control over the appearance of contour lines and line labels. If cnLinesOn is set False, no lines will appear regardless of the values of any cnLevelFlags elements; likewise, if cnLineLabelsOn is False, no line labels will appear.

If cnMonoLevelFlag is False and you do not explicitly set cnLevelFlags, the ContourPlot object will set its elements for you based on the value of cnLineLabelInterval. Elements will be set to LineOnly except that if cnLineLabelInterval is greater than 0, elements separated by the interval of cnLineLabelInterval will be set to LineAndLabel. This effect will occur both at initialization and any time you explicitly set cnLineLabelInterval.

Default: <dynamic>

cnLevelSelectionMode

This enumerated resource of type NhlTLevelSelectionMode provides four methods for selecting the contour intervals displayed in a plot:

AutomaticLevels

Ordinarily this mode determines contour levels by picking a spacing value from a set of relatively "round" numbers scaled by powers of 10 to the range of the data. This set of numbers is as follows: 1.0, 2.0, 2.5, 4.0, 5.0. The number of levels chosen will be as close as possible to the value of cnMaxLevelCount without exceeding it. Once the spacing is chosen, the minimum contour level is set to the value of the least multiple of the spacing greater than the minimum data value. Likewise the maximum contour level becomes the greatest multiple of the spacing less than the maximum data value. Based on these values, ContourPlot sets the resources cnLevelSpacingF, cnMinLevelValF, and cnMaxLevelValF appropriately.

On the other hand, if you explicitly set the resource cnLevelSpacingF to a valid value greater than 0.0 and less than the range of the data, it will be used as the interval spacing. The minimum and maximum levels are calculated as before. If as a consequence, cnMaxLevelCount is less than the number of levels so specified, it will be set to the number of levels actually needed. However, if the choice of spacing causes the absolute maximum number of levels, currently 255, to be exceeded, ContourPlot will issue a warning message and recalculate the spacing as previously described.

In any case, ContourPlot sets the elements of the array resource cnLevels to the values of the contour levels chosen and the read-only resource cnLevelCount to the number of levels.

ManualLevels

ManualLevels mode bases the choice of contour levels on the values of the resources cnLevelSpacingF, cnMinLevelValF, and cnMaxLevelValF. Starting at cnMinLevelValF, contour levels are created at intervals spaced by the value of cnLevelSpacingF until cnMaxLevelValF is reached. The final contour level will always be cnMaxLevelValF. ContourPlot sets elements of the array resource cnLevels to the values of each contour level chosen and the read-only resource cnLevelCount to the number of levels. If the current value of cnMaxLevelCount is less than cnLevelCount, it is reset to the value of cnLevelCount. However, if the level count would exceed the absolute maximum number of levels, currently 255, ContourPlot issues a warning and chooses a new value of cnLevelSpacingF based on the value of cnMaxLevelCount.

If you choose ManualLevels selection mode when the ContourPlot object is created, and if you do not set cnMinLevelValF, ContourPlot will choose levels as if you had set AutomaticLevels mode. If you set cnMinLevelValF only, a default spacing is used, and the value of cnMaxLevelValF is determined as it would be for AutomaticLevels mode.

ExplicitLevels

This mode allows you to specify the value of each contour level by explicitly setting the contents of the cnLevels array. If you choose ExplicitLevels selection mode when creating a ContourPlot object, but do not specify the contents of the cnLevels array, ContourPlot will choose levels as if you had specified AutomaticLevels mode. Thereafter, when you set ExplicitLevels mode, ContourPlot uses the current contents of cnLevels, whether or not you set it explicitly.

If the number of elements in cnLevels exceeds the absolute maximum number of levels (currently 255), ContourPlot issues a warning and the mode defaults to AutomaticLevels. Note that ContourPlot always sorts the elements of cnLevels into a monotonically increasing sequence. After sorting, cnMinLevelValF is set equal to the value of first element of cnLevels, and cnMaxLevelValF is set to the value of the last element. cnLevelSpacingF is set to the average value of the spacing separating each level.

EqualSpacedLevels

For this mode, ContourPlot divides the range spanning the dataset minimum and maximum values into cnMaxLevelCount+1 equally spaced intervals. cnLevelSpacingF is set to the value of this interval. cnMinLevelValF is set to the value of the dataset minimum plus the value of cnLevelSpacingF. cnMaxLevelValF is set to the value of the dataset maximum minus the value of cnLevelSpacingF. This results in cnMaxLevelCount levels; therefore ContourPlot sets the read-only resource cnLevelCount equal to cnMaxLevelCount.

Default: AutomaticLevels

cnLevelSpacingF

When the cnLevelSelectionMode is ManualLevels or when the cnLevelSelectionMode is AutomaticLevels, and cnLevelSpacingF is explicitly set, cnLevelSpacingF determines the spacing between contour intervals. Otherwise, the ContourPlot object sets the value of cnLevelSpacingF based on the contour levels actually chosen. When the cnLevelSelectionMode is ExplicitLevels, cnLevelSpacingF will be set to the arithmetic average of the spacing between levels.

Default: 5.0

cnLevels

An array of floats containing the contour levels used to render the contour plot. If the cnLevelSelectionMode is ExplicitLevels, you may set these values yourself. Otherwise, the ContourPlot object sets the elements of this array.

Default: <dynamic>

cnLineColor

When cnMonoLineColor is set True, this resource of type NhlTColorIndex or a named color (string). sets a uniform color for all contour lines.

Default: Foreground (1)

cnLineColors

When cnMonoLineColor is False, each element of this array resource of type NhlTColorIndexGenArray or a named color (string) individually sets the color of the contour line drawn at the corresponding contour level. If the array is not set explicitly, it will dynamically default to a set of colors spread numerically over the range of defined HLU color indexes. The colors used will therefore depend on the number of contour levels. If the array currently contains fewer elements than cnLevelCount, more elements will be added to the array and given values according to the default color assignment scheme; existing elements with valid color index values will not be modified.

Default: <dynamic>

cnLineDashPattern

When cnMonoLineDashPattern is set True, this resource of type NhlTDashIndex sets a uniform dash pattern for all contour lines.

Default: SolidLine (0)

cnLineDashPatterns

When cnMonoLineDashPattern is False, this array resource of type NhlTDashIndexGenArray individually sets the dash pattern of a contour line drawn at the corresponding contour level. If the array is not set explicitly, the ContourPlot object will assign sequential dash pattern indexes to each array element--starting with dash pattern index 1, not "SolidLine" (0)--up to the maximum number of existing dash patterns. Thereafter, it will repeat the sequence using modular arithmetic. If the array currently contains fewer elements than cnLevelCount, more elements will be added to the array and given values according to the same assignment scheme; existing elements with valid dash pattern index values will not be modified.

Default: <dynamic>

cnLineDashSegLenF

This resource indicates the length of each segment of the dash patterns used to draw contour lines. It is the length in NDC units before the dash pattern repeats itself. If cnLineLabelPlacementMode is set to Constant the line labels are rendered as part of the dash pattern, and therefore cnLineDashSegLenF also controls the spacing between the line labels.

cnLineDashSegLenF automatically scales with changes in the size of the viewport of the ContourPlot object. ContourPlot sets its default value dynamically based on the ratio of the actual plot viewport width to the reference viewport width.

Default: 0.15 (for a viewport width of 0.6)

cnLineDrawOrder

This resource of type NhlTDrawOrder determines when the contour lines are drawn relative to other elements of the plot. There are three choices:

PreDraw: Draw the contour lines before the standard draw; the lines will be overlaid by any subsequently drawn elements.
Draw: Draw the lines during the standard draw; the lines will overlay any elements drawn during the predraw phase, but will underlie elements drawn during the postdraw phase.
PostDraw: Draw the lines after the standard draw; the lines will overlay any elements drawn during the predraw and draw phases.

Default: Draw

cnLineLabelAngleF

When cnLineLabelAngleF has a value less than 0.0, ContourPlot line labels are angled in the direction of the tangent of the contour line at the location of the label. Otherwise, cnLineLabelAngleF specifies the angle, in degrees, of all contour line labels. If cnLineLabelPlacementMode is set to Constant, this resource has no effect: the line labels are always placed along the contour line.

Default: -1.0

cnLineLabelBackgroundColor

This resource sets the background color used to fill the box surrounding each line label. If you do not want the box to be filled at all, set cnLineLabelBackgroundColor to Transparent (-1). If cnLineLabelPlacementMode is set to Constant, this resource has no effect: a boxed background is not available.

You can use a color index value (integer) or a named color (string).

Default: Background (0)

cnLineLabelConstantSpacingF

Default: 0.0

cnLineLabelCount

Each time a ContourPlot is drawn, the read-only resource cnLineLabelCount is updated with the number of line labels actually rendered in the plot. Until the plot is drawn for the first time cnLineLabelCount has the value 0;

Default: 0

cnLineLabelDensityF

The cnLineLabelDensityF resource provides simple, though not very precise, control over the number of line labels that appear in a contourplot. It has an effect only when cnLineLabelPlacementMode is set to Computed or Randomized. cnLineDashSegLenF controls the density of Constant mode line labels..

If cnLineLabelDensityF is set to its default value, 0.0, it has no effect and line label density can only be controlled by setting the appropriate low level parameters via the resource cnConpackParams. Setting cnLineLabelDensityF to 1.0 causes ContourPlot to use the default settings of the applicable low level resources, overriding any that are set through the cnConpackParams resource. Increase the number of line labels by setting cnLineLabelDensityF to values greater than 1.0, or decrease the number by setting it to positive values less than 1.0. You can obtain a count of the line labels drawn in the most recent rendering of the ContourPlot by retrieving the resource cnLineLabelCount.

Default: 0.0

cnLineLabelFont

This resource of type NhlTFont specifies the font used to render line labels.

Default: "pwritx"

cnLineLabelFontAspectF

This resource determines the shape of the line label characters. Values increasing from 1.0 result in thinner characters. Values decreasing from 1.0 make the characters wider. Values less than or equal to 0.0 result in a WARNING message and a restoration of the default value.

Default: 1.3125

cnLineLabelFontColor

When cnMonoLineLabelFontColor is set True, this resource of type NhlTColorIndex or a named color (string) sets a uniform color for all contour line labels.

Default: Foreground (1)

cnLineLabelFontColors

When cnMonoLineLabelFontColor is False, each element of this array of type NhlTColorIndexGenArray or named color (string) specifies the color of a contour line label. If the array is not set explicitly, it will dynamically default to a set of colors spread numerically over the range of defined HLU color indexes. The colors used will therefore depend on the number of contour levels. If the array currently contains fewer elements than cnLevelCount, more elements will be added to the array and given values according to the default color assignment scheme; existing elements with valid color index values will not be modified.

You can use an array of color index values (integer) or named colors (string).

Default: <dynamic>

cnLineLabelFontHeightF

This resource controls the height, in NDC units, of characters used in the text of line labels. The character width scales proportionally, unless you also modify the aspect ratio using the cnLineLabelFontAspectF resource. The line label text height scales with changes to the viewport width, unless you explicitly set cnLineLabelFontHeightF during the same call.

Default: <dynamic> -- 0.012 for a viewport width of 0.6

cnLineLabelFontQuality

This resource of type NhlTFontQuality determines the quality of the font used to draw ContourPlot line labels.

Default: High

cnLineLabelFontThicknessF

Sets the thickness of the line used to draw line label text. The value acts as a multiplier of a (device-dependent) unit thickness. This resource is ignored when the cnLineLabelFont specifies a filled font (font indexes 21-22, 25-26, 29-30, and 33-37).

Default: 1.0

cnLineLabelFormat

The cnLineLabelFormat resource is a string that specifies the printing format for the numeric portion of line labels according to the HLU Floating Point Format Specification scheme. It does not apply when the user explicitly sets the elements of cnLineLabelStrings. If any of the numerical format parameters have the dynamic attribute on, the corresponding parameter in the cnMaxDataValueFormat resource determines the parameter's value. The default value uses the shorthand notation '*+' to cause all numeric format parameters to be determined dynamically.

Note that since the labels used for the ContourPlot LabelBar are copied from the cnLineLabelStrings resource the cnLineLabelFormat resource also controls the formatting of the LabelBar labels. This is true whether cnLineLabelsOn is set True or False.

Default: "*+^sg"

cnLineLabelFuncCode

This resource of type NhlTCharacter sets the function code character that the low level utilities will use when parsing the label string.

Default: :

cnLineLabelInterval

When cnMonoLevelFlag is False and you do not explicitly set the array cnLevelFlags, a positive value of cnLineLabelInterval sets the number of levels from a labeled level to the next labeled level. The interval is generated in both directions from the contour level requiring the least number of significant digits to express (with the value 0.0 considered to require zero significant digits). If cnLineLabelInterval is less than or equal to zero, then no contour levels are labeled.

Default: 2

cnLineLabelPerimColor

This resource sets the HLU color index used to draw the perimeter of the line label box. If cnLineLabelPlacementMode is set to Constant, this resource has no effect: no perimeter can be drawn around the label.

You can use a color index value (integer) or a named color (string).

Default: Foreground (1)

cnLineLabelPerimOn

cnLineLabelPerimOn is a boolean resource that determines whether ContourPlot will draw an outline around the perimeter of the box surrounding contour line labels. If set False, no outline will be drawn. If cnLineLabelPlacementMode is set to Constant, this resource has no effect: no perimeter can be drawn around the label.

Default: True

cnLineLabelPerimSpaceF

cnLineLabelPerimSpaceF determines the spacing or margin between the text of the line label and the edge of the line label box as a fraction of the current line label text height. If cnLineLabelPlacementMode is set to Constant, this resource has no effect: no perimeter can be drawn around the label.

Default: 0.33

cnLineLabelPerimThicknessF

This resource determines the thickness of the perimeter line around the line label box. The value acts as a multiplier of a (device-dependent) unit thickness. If cnLineLabelPlacementMode is set to Constant, this resource has no effect: no perimeter can be drawn around the label.

Default: 1.0

cnLineLabelPlacementMode

This resource of type NhlTcnLineLabelPlacementMode determines the algorithm ContourPlot uses to place line labels. There are three choices:

Constant: ContourPlot draws line labels as an integral part of the line dash pattern. As a result, the labels are equally spaced along the lines. You can control the spacing between the labels by setting the cnLineDashSegLenF resource.
Randomized: ContourPlot places labels using a randomizing algorithm to vary the distance between labels. You can increase or decrease the overall number of labels using the cnLineLabelDensityF resource. Or for more precise control, you can specify the appropriate low level parameter values yourself using cnConpackParams.
Computed: ContourPlot uses a more complex algorithm involving the local gradient, number of contour lines in a region, cumulative change in direction, and an optimum distance value to determine the best location for line labels. This method usually gives the best-looking results. You can increase or decrease the overall number of labels using the cnLineLabelDensityF resource. Or for more precise control, you can specify the appropriate low level parameter values yourself using cnConpackParams.