Contour Properties

Control contour appearance and behavior

Contour properties control the appearance and behavior of contour objects. By changing property values, you can modify certain aspects of the contour.

Starting in R2014b, you can use dot notation to refer to a particular object and property:

[~,h] = contour(...);
c = h.LineColor;
h.ShowText = 'on';

If you are using an earlier release, use the get and set functions to query and set properties.

Line Appearance

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LineColorColor of contour lines'flat' (default) | 'none' | RGB triplet | color string

Color of contour lines, specified as one of these values:

  • 'flat' — Use a different color for each contour line, determined by its contour value, the colormap, and the scaling of data values into the colormap. For more information on color scaling, see caxis.

  • 'none' — Do not draw the contour lines.

  • RGB triplet or color string — Use the same color for all contour lines. Specify the color using an RGB triplet or a color string.

An RGB triplet is a three-element row vector whose elements specify the intensities of the red, green, and blue components of the color. The intensities must be in the range [0,1], for example, [0.4 0.6 0.7]. This table lists RGB triplet values that have equivalent color strings.

Long NameShort NameRGB Triplet
'yellow''y'[1 1 0]
'magenta''m'[1 0 1]
'cyan''c'[0 1 1]
'red''r'[1 0 0]
'green''g'[0 1 0]
'blue''b'[0 0 1]
'white''w'[1 1 1]
'black'k'[0 0 0]

LineStyleLine style'-' (default) | '--' | ':' | '-.' | 'none'

Line style, specified as one of the line style strings listed in this table.

StringLine StyleResulting Line
'-'Solid line

'--'Dashed line

':'Dotted line

'-.'Dash-dotted line

'none'No lineNo line

LineWidthWidth of contour lines0.5 (default) | positive value

Width of contour lines, specified as a positive value in points. One point equals 1/72 inch.

Example: 2

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64

Contour Levels

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LevelListContour levelsempty matrix (default) | vector of z values

Contour levels, specified as a vector of z values. By default, the contour function chooses values that span the range of values in the ZData property.

Setting this property sets the associated mode property to manual.

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64

LevelListModeSelection mode for LevelList'auto' (default) | 'manual'

Selection mode for the LevelList, specified as one of these values:

  • 'auto' — Determine the values based on the ZData values.

  • 'manual' — Use manually specified values. To specify the values, set the LevelList property. When the mode is manual, the contour function does not change the values as you change ZData.

LevelStepSpacing between contour lines0 (default) | scalar numeric value

Spacing between contour lines, specified as a scalar numeric value. For example, specify a value of 2 to draw contour lines at increments of 2. The contour function determines the contour interval based on the ZData values.

Setting this property sets the associated mode property to manual.

Example: 3.4

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64

LevelStepModeSelection mode for LevelStep'auto' (default) | 'manual'

Selection mode for the LevelStep, specified as one of these values:

  • 'auto' — Determine the value based on the ZData values.

  • 'manual' — Use a manually specified value. To specify the value, set the LevelStep property. When the mode is manual, the contour function does not change the value as you change ZData.

Contour Labels

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ShowTextContour line labels'off' (default) | 'on'

Contour line labels, specified as one of these values:

  • 'off' — Do not label the contour lines.

  • 'on' — Display text labels on each contour line indicating the contour value.

LabelSpacingSpacing between contour line labels144 (default) | numeric scalar

Spacing between contour line labels, specified as a numeric scalar in point units. One point equals 1/72 inch. You must set the ShowText property to 'on' for the LabelSpacing property to have an effect.

If you use the clabel function to display the labels, then the LabelSpacing property has no effect. The contour plot contains a single label per line instead.

Example: 36

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64

TextListContour lines to labelempty matrix (default) | vector of real values

Contour lines to label, specified as a vector of real values.

Setting this property sets the associated mode property to manual.

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64

TextListModeSelection mode for TextList'auto' (default) | 'manual'

Selection mode for the TextList, specified as one of these values:

  • 'auto' — Use values equal to the values of the LevelList property. The contour plot includes a text label for each line.

  • 'manual' — Use manually specified values. Specify the values by setting the TextList property.

TextStepInterval between labeled contour lines0 (default) | scalar numeric value

Interval between labeled contour lines, specified as a scalar numeric value. By default, the contour plot includes a label for every contour line when the ShowText property is set to 'on'.

Setting this property sets the associated mode property to manual.

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64

TextStepModeSelection mode for TextStep'auto' (default) | 'manual'

Selection mode for the TextStep, specified as one of these values:

  • 'auto' — Determine value based on the ZData values. If the ShowText property is set to 'on', then the contour function labels every contour line.

  • 'manual' — Use a manually specified value. To specify the value, set the TextStep property.

Filled Contours

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FillFill between contour lines'off' (default) | 'on'

Fill between contour lines, specified as one of these values:

  • 'off' — Do not fill the spaces between contour lines with a color. This is the default value when you create the contour chart using the contour or contour3 functions.

  • 'on' — Fill the spaces between contour lines with color. This is the default value when you create the contour chart using the contourf function.

Contour Matrix

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ContourMatrixContour line definitions[] (default) | two-row matrix

This property is read only.

Contour line definitions, returned as a two-row matrix. Each contour line in the plot has an associated definition. If there are a total of N contour lines in the plot, then the contour matrix consists of N definitions:

C = [C(1) C(2)...C(k)...C(N)]

Each contour line definition follows this pattern:

C(k) = [level   x(1) x(2)...
        numxy   y(1) y(2)... ]

The first entry, level, indicates the contour level where the contour line is drawn. Beneath the contour level is the number of (x,y) vertices that define the contour line. The remaining columns contain the data for each of the vertices. If the first and last vertices are the same, then the contour line is a closed loop. If a particular contour level has multiple contour lines in the graph, then the matrix contains a separate definition for each line.

Example

Create a contour plot of values from the peaks function.

[x,y,z] = peaks(3);
[C,h] = contour(x,y,z);

Access the contour matrix using either the output argument C or the ContourMatrix property of the contour object (h.ContourMatrix). The contour matrix contains definitions for each of the seven contour lines. The circles in this matrix show the beginnings of the contour line definitions.

The first definition in the matrix indicates that there is a contour line drawn at the -0.2 level , consisting of the three vertices (1.8165,1), (2,1.0367), and (2.1835,1). Since the first and last vertices are not the same, the contour line is not a closed loop. The second and third definitions indicate that there are two closed loops at the 0 level.

Plotted Data

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XDatax values[] (default) | vector or matrix

x values, specified as a vector or matrix.

  • If XData is a vector, then length(XData) must equal size(ZData,2) and YData must also be a vector. The XData values must be strictly increasing or strictly decreasing and cannot contain any duplicates.

  • If XData is a matrix, then size(XData) and size(YData) must equal size(ZData). Typically, you should set the XData values so that the columns are strictly increasing or strictly decreasing and the rows are uniform (or the rows are strictly increasing or strictly decreasing and the columns are uniform).

Setting this property sets the associated mode property to manual.

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64 | logical

YDatay values[] (default) | vector or matrix

y values, specified as a vector or matrix.

  • If YData is a vector, then length(YData) must equal size(ZData,1) and XData must also be a vector. The XData values must be strictly increasing or strictly decreasing and cannot contain any duplicates.

  • If YData is a matrix, then size(XData) and size(YData) must equal size(ZData). Typically, you should set the YData values so that the columns are strictly increasing or strictly decreasing and the rows are uniform (or the rows are strictly increasing or strictly decreasing and the columns are uniform).

Setting this property sets the associated mode property to manual.

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64 | logical

ZDataData that defines surface to contour[] (default) | matrix

Data that defines the surface to contour, specified as a matrix. ZData must be at least a 2-by-2 matrix.

Setting this property sets the associated mode property to manual.

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64

XDataSourceVariable linked to XData'' (default) | string containing MATLAB® workspace variable name

Variable linked to XData, specified as a string containing a MATLAB workspace variable name. MATLAB evaluates the variable in the base workspace to generate the XData.

By default, there is no linked variable so the value is an empty string, ''. If you link a variable, then MATLAB does not update the XData values immediately. To force an update of the data values, use the refreshdata function.

    Note:   If you change one data source property to a variable that contains data of a different dimension, you might cause the function to generate a warning and not render the graph until you have changed all data source properties to appropriate values.

Example: 'x'

YDataSourceVariable linked to YData'' (default) | string containing MATLAB workspace variable name

Variable linked to YData, specified as a string containing a MATLAB workspace variable name. MATLAB evaluates the variable in the base workspace to generate the YData.

By default, there is no linked variable so the value is an empty string, ''. If you link a variable, then MATLAB does not update the YData values immediately. To force an update of the data values, use the refreshdata function.

    Note:   If you change one data source property to a variable that contains data of a different dimension, you might cause the function to generate a warning and not render the graph until you have changed all data source properties to appropriate values.

Example: 'y'

ZDataSourceVariable linked to ZData'' (default) | string containing MATLAB workspace variable name

Variable linked to ZData, specified as a string containing a MATLAB workspace variable name. MATLAB evaluates the variable in the base workspace to generate the ZData.

By default, there is no linked variable so the value is an empty string, ''. If you link a variable, then MATLAB does not update the ZData values immediately. To force an update of the data values, use the refreshdata function.

    Note:   If you change one data source property to a variable that contains data of a different dimension, you might cause the function to generate a warning and not render the graph until you have changed all data source properties to appropriate values.

Example: 'z'

XDataModeSelection mode for XData'auto' (default) | 'manual'

Selection mode for the XData, specified as one of these values:

  • 'auto' — Set the XData using the column indices of ZData.

  • 'manual' — Use manually specified values. To specify the values, set the XData property directly, or specify the input argument X to the contour, contourf, or contour3 function.

YDataModeSelection mode for XData'auto' (default) | 'manual'

Selection mode for the YData, specified as one of these values:

  • 'auto' — Set the YData using the row indices of ZData.

  • 'manual' — Use manually specified values. To specify the values, set the YData property directly, or specify the input argument Y to the contour, contourf, or contour3 function.

Visibility

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VisibleVisibility of contour'on' (default) | 'off'

Visibility of contour, specified as one of these values:

  • 'on' — Display the contour.

  • 'off' — Hide the contour without deleting it. You still can access the properties of an invisible contour object.

ClippingClipping of contour to axes limits'on' (default) | 'off'

Clipping of contour to the axes limits, specified as one of these values:

  • 'on' — Do not display parts of the contour that are outside the axes limits.

  • 'off' — Display the entire contour, even if parts of it appear outside the axes limits. Parts of the contour might appear outside the axes limits if you create a plot, set hold on, freeze the axis scaling, and then create the contour that is larger than the original plot.

EraseMode(removed) Technique to draw and erase objects'normal' (default) | 'none' | 'xor' | 'background'

    Note:   EraseMode has been removed. You can delete code that accesses the EraseMode property with minimal impact. If you were using EraseMode to create line animations, use the animatedline function instead.

Technique to draw and erase objects, specified as one of these values:

  • 'normal' — Redraw the affected region of the display, performing the three-dimensional analysis necessary to correctly render all objects. This mode produces the most accurate picture, but is the slowest. The other modes are faster, but do not perform a complete redraw and, therefore, are less accurate.

  • 'none' — Do not erase the object when it is moved or destroyed. After you erase the object with EraseMode,'none', it is still visible on the screen. However, you cannot print the object because MATLAB does not store any information on its former location.

  • 'xor' — Draw and erase the object by performing an exclusive OR (XOR) with the color of the screen beneath it. This mode does not damage the color of the objects beneath it. However, the object color depends on the color of whatever is beneath it on the display.

  • 'background' — Erase the object by redrawing it in the axes background color, or the figure background color if the axes Color property is 'none'. This damages objects that are behind the erased object, but properly colors the erased object.

MATLAB always prints figures as if the EraseMode property of all objects is set to 'normal'. This means graphics objects created with EraseMode set to 'none', 'xor', or 'background' can look different on screen than on paper. On screen, MATLAB mathematically combines layers of colors and ignores three-dimensional sorting to obtain greater rendering speed. However, MATLAB does not apply these techniques to the printed output. Use the getframe command or other screen capture applications to create an image of a figure containing nonnormal mode objects.

Parent/Child

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ParentParent of contouraxes object | group object | transform object

Parent of contour, specified as an axes, group, or transform object.

ChildrenChildren of contourempty GraphicsPlaceholder array

The contour has no children. You cannot set this property.

HandleVisibilityVisibility of object handle'on' (default) | 'off' | 'callback'

Visibility of object handle in the Children property of the parent, specified as one of these values:

  • 'on' — List the contour object.

  • 'off' — Do not list the contour object. Use this option to hide object handles when a callback invokes a function that could damage the GUI, such as evaluating a user-typed string.

  • 'callback' — List the contour object in the Children property of the parent from within callbacks or functions invoked by callbacks, but not from within functions invoked from the command line. Use this option to protect a GUI from command-line users, while allowing callbacks to have access to objects.

If the contour object is not listed in the Children property of the parent, then functions that obtain object handles by searching the object hierarchy or querying handle properties cannot return it. This includes get, findobj, gca, gcf, gco, newplot, cla, clf, and close.

Hidden object handles are still valid. Set the root ShowHiddenHandles property to 'on' to list all object handles regardless of their HandleVisibility property setting.

Identifiers

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TypeType of graphics object'contour'

This property is read only.

Type of graphics object, returned as the string 'contour'.

TagUser-specified tag'' (default) | any string

Tag to associate with the contour, specified as a string. Tags provide a way to identify graphics objects. Use this property to find all objects with a specific tag within a plotting hierarchy, for example, searching for the tag using findobj.

Example: 'January Data'

UserDataData to associate with contour[] (default) | scalar, vector, or matrix | cell array | character array | table | structure

Data to associate with the contour object, specified as a scalar, vector, matrix, cell array, character array, table, or structure. MATLAB does not use this data.

To associate multiple sets of data or to attach a field name to the data, use the getappdata and setappdata functions.

Example: 1:100

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64 | logical | char | struct | table | cell

DisplayNameText used by legend'' (default) | string

Text used by the legend, specified as a string. The text appears next to an icon of the contour.

  • If you specify text for the contour object as an input argument to the legend function, then the legend uses the specified text and updates the DisplayName.

  • If you do not specify text for the contour object as an input argument to the legend function, then the legend uses the text in the DisplayName property. If the DisplayName property does not contain any text, then the legend generates a string. The string has the form 'dataN', where N is the number assigned to the contour object based on its location in the list of legend entries.

If you edit interactively the string in an existing legend, then MATLAB updates the DisplayName to the edited string.

Example: 'Text Description'

AnnotationLegend icon display styleAnnotation object

This property is read only.

Legend icon display style, returned as an Annotation object. Use this object to include or exclude the contour from a legend.

  1. Query the Annotation property to get the Annotation object.

  2. Query the LegendInformation property of the Annotation object to get the LegendEntry object.

  3. Specify the IconDisplayStyle property of the LegendEntry object to one of these values:

    • 'on' — Include the contour object in the legend as one entry (default).

    • 'off' — Do not include the contour object in the legend.

    • 'children' — Include only children of the contour object as separate entries in the legend.

If a legend already exists and you change the IconDisplayStyle setting, then you must call legend to update the display.

Interactive Control

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ButtonDownFcnMouse-click callback'' (default) | function handle | cell array | string

Mouse-click callback, specified as one of these values:

  • Function handle

  • Cell array containing a function handle and additional arguments

  • String that is a valid MATLAB command or function, which is evaluated in the base workspace (not recommended)

Use this property to execute code when you click the contour. If you specify this property using a function handle, then MATLAB passes two arguments to the callback function when executing the callback:

  • The contour object — You can access properties of the contour object from within the callback function.

  • Event data — This argument is empty for this property. Replace it with the tilde character (~) in the function definition to indicate that this argument is not used.

For more information on how to use function handles to define callback functions, see Callback Definition.

    Note:   If the PickableParts property is set to 'none' or if the HitTest property is set to 'off', then this callback does not execute.

Example: @myCallback

Example: {@myCallback,arg3}

UIContextMenuContext menuuicontextmenu object

Context menu, specified as a uicontextmenu object. Use this property to display a context menu when you right-click the contour. Create the context menu using the uicontextmenu function.

    Note:   If the PickableParts property is set to 'none' or if the HitTest property is set to 'off', then the context menu does not appear.

SelectedSelection state'off' (default) | 'on'

Selection state, specified as one of these values:

  • 'on' — Selected. If you click the contour when in plot edit mode, then MATLAB sets its Selected property to 'on'. If the SelectionHighlight property also is set to 'on', then MATLAB displays selection handles around the contour.

  • 'off' — Not selected.

SelectionHighlightDisplay of selection handles when selected'on' (default) | 'off'

Display of selection handles when selected, specified as one of these values:

  • 'on' — Display selection handles when the Selected property is set to 'on'.

  • 'off' — Never display selection handles, even when the Selected property is set to 'on'.

Callback Execution Control

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PickablePartsAbility to capture mouse clicks'visible' (default) | 'none'

Ability to capture mouse clicks, specified as one of these values:

  • 'visible' — Can capture mouse clicks only when visible. The Visible property must be set to 'on'. The HitTest property determines if the contour responds to the click or if an ancestor does.

  • 'none' — Cannot capture mouse clicks. Clicking the contour passes the click to the object below it in the current view of the figure window. The HitTest property of the contour has no effect.

HitTestResponse to captured mouse clicks'on' (default) | 'off'

Response to captured mouse clicks, specified as one of these values:

  • 'on' — Trigger the ButtonDownFcn callback of the contour. If you have defined the UIContextMenu property, then invoke the context menu.

  • 'off' — Trigger the callbacks for the nearest ancestor of the contour that has a HitTest property set to 'on' and a PickableParts property value that enables the ancestor to capture mouse clicks.

    Note:   The PickableParts property determines if the contour object can capture mouse clicks. If it cannot, then the HitTest property has no effect.

HitTestArea(removed) Extents of clickable area for contour'off' (default) | 'on'

    Note:   HitTestArea has been removed. Use PickableParts instead.

Extents of clickable area for contour, specified as one of these values:

  • 'off' — Click the contour plot to select it. This is the default value.

  • 'on' — Click anywhere within the extent of the contour plot to select it, that is, anywhere within the rectangle that encloses the contour plot.

Example: 'off'

InterruptibleCallback interruption'on' (default) | 'off'

Callback interruption, specified as 'on' or 'off'. The Interruptible property determines if a running callback can be interrupted.

    Note:   There are two callback states to consider:

    • The running callback is the currently executing callback.

    • The interrupting callback is a callback that tries to interrupt the running callback.

    Whenever MATLAB invokes a callback, that callback attempts to interrupt a running callback. The Interruptible property of the object owning the running callback determines if interruption is allowed. If interruption is not allowed, then the BusyAction property of the object owning the interrupting callback determines if it is discarded or put in the queue.

If the ButtonDownFcn callback of the contour is the running callback, then the Interruptible property determines if it another callback can interrupt it:

  • 'on' — Interruptible. Interruption occurs at the next point where MATLAB processes the queue, such as when there is a drawnow, figure, getframe, waitfor, or pause command.

    • If the running callback contains one of these commands, then MATLAB stops the execution of the callback at this point and executes the interrupting callback. MATLAB resumes executing the running callback when the interrupting callback completes. For more information, see Interrupt Callback Execution.

    • If the running callback does not contain one of these commands, then MATLAB finishes executing the callback without interruption.

  • 'off' — Not interruptible. MATLAB finishes executing the running callback without any interruptions.

BusyActionCallback queuing'queue' (default) | 'cancel'

Callback queuing specified as 'queue' or 'cancel'. The BusyAction property determines how MATLAB handles the execution of interrupting callbacks.

    Note:   There are two callback states to consider:

    • The running callback is the currently executing callback.

    • The interrupting callback is a callback that tries to interrupt the running callback.

    Whenever MATLAB invokes a callback, that callback attempts to interrupt a running callback. The Interruptible property of the object owning the running callback determines if interruption is allowed. If interruption is not allowed, then the BusyAction property of the object owning the interrupting callback determines if it is discarded or put in the queue.

If the ButtonDownFcn callback of the contour tries to interrupt a running callback that cannot be interrupted, then the BusyAction property determines if it is discarded or put in the queue. Specify the BusyAction property as one of these values:

  • 'queue' — Put the interrupting callback in a queue to be processed after the running callback finishes execution. This is the default behavior.

  • 'cancel' — Discard the interrupting callback.

Creation and Deletion Control

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CreateFcnCreation callback'' (default) | function handle | cell array | string

Creation callback, specified as one of these values:

  • Function handle

  • Cell array containing a function handle and additional arguments

  • String that is a valid MATLAB command or function, which is evaluated in the base workspace (not recommended)

Use this property to execute code when you create the contour. Setting the CreateFcn property on an existing contour has no effect. You must define a default value for this property, or define this property using a Name,Value pair during contour creation. MATLAB executes the callback after creating the contour and setting all of its properties.

If you specify this callback using a function handle, then MATLAB passes two arguments to the callback function when executing the callback:

  • The contour object — You can access properties of the contour object from within the callback function. You also can access the contour object through the CallbackObject property of the root, which can be queried using the gcbo function.

  • Event data — This argument is empty for this property. Replace it with the tilde character (~) in the function definition to indicate that this argument is not used.

For more information on how to use function handles to define callback functions, see Callback Definition.

Example: @myCallback

Example: {@myCallback,arg3}

DeleteFcnDeletion callback'' (default) | function handle | cell array | string

Deletion callback, specified as one of these values:

  • Function handle

  • Cell array containing a function handle and additional arguments

  • String that is a valid MATLAB command or function, which is evaluated in the base workspace (not recommended)

Use this property to execute code when you delete the contour. MATLAB executes the callback before destroying the contour so that the callback can access its property values.

If you specify this callback using a function handle, then MATLAB passes two arguments to the callback function when executing the callback:

  • The contour object — You can access properties of the contour object from within the callback function. You also can access the contour object through the CallbackObject property of the root, which can be queried using the gcbo function.

  • Event data — This argument is empty for this property. Replace it with the tilde character (~) in the function definition to indicate that this argument is not used.

For more information on how to use function handles to define callback functions, see Callback Definition.

Example: @myCallback

Example: {@myCallback,arg3}

BeingDeletedDeletion status of contour'off' (default) | 'on'

This property is read only.

Deletion status of contour, returned as 'on' or 'off'. MATLAB sets the BeingDeleted property to 'on' when the delete function of the contour begins execution (see the DeleteFcn property). The BeingDeleted property remains set to 'on' until the contour no longer exists.

Check the value of the BeingDeleted property to verify that the contour is not about to be deleted before querying or modifying it.

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