surfc

Contour plot under surface plot

• 

Syntax

surfc(X,Y,Z)

surfc(X,Y,Z,C)

surfc(Z)

surfc(Z,C)

surfc(ax,___)

surfc(___,Name,Value)

sc = surfc(___)

Description

surfc(X,Y,Z) creates a three-dimensional surface plot with a contour plot underneath. A surface plot is a three-dimensional surface that has solid edge colors and solid face colors. The function plots the values in matrix Z as heights above a grid in the x-y plane defined by X and Y. The color of the surface varies according to the heights specified by Z.

surfc(X,Y,Z,C) additionally specifies the surface color.

surfc(Z) creates a surface and contour plot and uses the column and row indices of the elements in Z as the x- and y -coordinates.

surfc(Z,C) additionally specifies the surface color.

surfc(ax,___) plots into the axes specified by ax instead of the current axes. Specify the axes as the first input argument.

surfc(___,Name,Value) specifies surface properties using one or more name-value pair arguments. For example, 'FaceAlpha',0.5 creates a semitransparent surface.

sc = surfc(___) returns a graphics array that includes the chart surface object and the contour object. Use sc to modify the surface and contour plots after they are created. For a list of properties, see Surface Properties and Contour Properties.

Examples

Display Contour Plot Under Surface Plot

Create three matrices of the same size. Then plot them as a surface and display a contour plot under the surface plot. The surface uses Z for both height and color.

[X,Y] = meshgrid(1:0.5:10,1:20);
Z = sin(X) + cos(Y);
surfc(X,Y,Z)

Specify Colormap Colors for Surface and Contour Plot

Specify the colors for a surface and a contour plot by including a fourth matrix input, C. The surface plot uses Z for height and C for color. Specify the colors using a colormap, which uses single numbers to stand for colors on a spectrum. When you use a colormap, C is the same size as Z. Add a color bar to the graph to show how the data values in C correspond to the colors in the colormap.

[X,Y] = meshgrid(-3:.125:3);
Z = peaks(X,Y);
C = X.*Y;
surfc(X,Y,Z,C)
colorbar

Modify Appearance of Surface and Contour Plots

Create a blue surface plot with a contour plot underneath it by specifying the FaceColor name-value pair with 'b' as the value. To allow further modifications, assign the graphics array containing the surface and contour objects to the variable sc.

[X,Y] = meshgrid(-5:.5:5);
Z = Y.*sin(X) - X.*cos(Y);
sc = surfc(X,Y,Z,'FaceColor','b');

Index into sc to access and modify properties of the surface and contour plots after they are created. The surface plot is accessible as sc(1) and the contour plot as sc(2). For example, change the edge colors of the two plots by setting the EdgeColor properties.

sc(1).EdgeColor = 'r';
sc(2).EdgeColor = 'b';

Change Location of Contour Lines

The contour lines appear at the minimum z-level by default, but you can change the location by setting the ZLocation property.

Display the peaks data set as a surface plot with the contours at the minimum z-level. Specify a return argument when you call the surfc function so that you can access the Contour object.

Z = peaks;
sc = surfc(Z);

Get the current axes and extend the upper limit of the z-axis to 15. Then move the contours to the maximum z-level.

ax = gca;
ax.ZLim(2) = 15;
sc(2).ZLocation = 'zmax';

Input Arguments

X — x-coordinates

matrix | vector

x-coordinates, specified as a matrix the same size as Z, or as a vector with length n, where [m,n] = size(Z). If you do not specify values for X and Y, surfc uses the vectors (1:n) and (1:m).

When X is a matrix, the values must be strictly increasing or decreasing along one dimension and remain constant along the other dimension. The dimension that varies must be the opposite of the dimension that varies in Y. You can use the meshgrid function to create X and Y matrices.

When X is a vector, the values must be strictly increasing or decreasing.

The XData properties of the surface and contour objects store the x-coordinates.

Example: X = 1:10

Example: X = [1 2 3; 1 2 3; 1 2 3]

Example: [X,Y] = meshgrid(-5:0.5:5)

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

Y — y-coordinates

matrix | vector

y-coordinates, specified as a matrix the same size as Z or as a vector with length m, where [m,n] = size(Z). If you do not specify values for X and Y, surfc uses the vectors (1:n) and (1:m).

When Y is a matrix, the values must be strictly increasing or decreasing along one dimension and remain constant along the other dimension. The dimension that varies must be the opposite of the dimension that varies in X. You can use the meshgrid function to create X and Y matrices.

When Y is a vector, the values must be strictly increasing or decreasing.

The YData properties of the surface and contour objects store the y-coordinates.

Example: Y = 1:10

Example: Y = [1 1 1; 2 2 2; 3 3 3]

Example: [X,Y] = meshgrid(-5:0.5:5)

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

Z — z-coordinates

matrix

z-coordinates, specified as a matrix. Z must have at least two rows and two columns.

Z specifies the height of the surface plot at each x-y coordinate. If you do not specify the colors, then Z also specifies the surface colors.

The ZData properties of the surface and contour objects store the z-coordinates.

Example: Z = [1 2 3; 4 5 6]

Example: Z = sin(x) + cos(y)

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

C — Color array

matrix | m-by-n-by-3 array of RGB triplets

Color array, specified as an m-by-n matrix of colormap indices or as an m-by-n-by-3 array of RGB triplets, where Z is m-by-n.

• To use colormap colors, specify C as a matrix. For each grid point on the surface, C indicates a color in the colormap. The CDataMapping property of the surface object controls how the values in C correspond to colors in the colormap.

• To use truecolor colors, specify C as an array of RGB triplets.

For more information, see Differences Between Colormaps and Truecolor.

The CData property of the surface object stores the color array. For additional control over the surface coloring, use the FaceColor and EdgeColor properties.

ax — Axes to plot in

axes object

Axes to plot in, specified as an axes object. If you do not specify the axes, then surfc plots into the current axes.

Name-Value Arguments

Specify optional pairs of arguments as Name1=Value1,...,NameN=ValueN, where Name is the argument name and Value is the corresponding value. Name-value arguments must appear after other arguments, but the order of the pairs does not matter.

Before R2021a, use commas to separate each name and value, and enclose Name in quotes.

Example: surfc(X,Y,Z,'FaceAlpha',0.5,'EdgeColor','none') creates a semitransparent surface with no edges drawn.

Note

The properties listed here are only a subset. For a full list, see Surface Properties.

EdgeColor — Edge line color

[0 0 0] (default) | 'none' | 'flat' | 'interp' | RGB triplet | hexadecimal color code | 'r' | 'g' | 'b' | ...

Edge line color, specified as one of the values listed here. The default color of [0 0 0] corresponds to black edges.

Value	Description
'none'	Do not draw the edges.
'flat'	Use a different color for each edge based on the values in the CData property. First you must specify the CData property as a matrix the same size as ZData. The color value at the first vertex of each face (in the positive x and y directions) determines the color for the adjacent edges. You cannot use this value when the EdgeAlpha property is set to 'interp'.
'interp'	Use interpolated coloring for each edge based on the values in the CData property. First you must specify the CData property as a matrix the same size as ZData. The color varies across each edge by linearly interpolating the color values at the vertices. You cannot use this value when the EdgeAlpha property is set to 'flat'.
RGB triplet, hexadecimal color code, or color name	Use the specified color for all the edges. This option does not use the color values in the CData property.

RGB triplets and hexadecimal color codes are useful for specifying custom colors.

• 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].

• A hexadecimal color code is a character vector or a string scalar that starts with a hash symbol (#) followed by three or six hexadecimal digits, which can range from 0 to F. The values are not case sensitive. Thus, the color codes "#FF8800", "#ff8800", "#F80", and "#f80" are equivalent.

Alternatively, you can specify some common colors by name. This table lists the named color options, the equivalent RGB triplets, and hexadecimal color codes.

Color Name	Short Name	RGB Triplet	Hexadecimal Color Code	Appearance
"red"	"r"	[1 0 0]	"#FF0000"
"green"	"g"	[0 1 0]	"#00FF00"
"blue"	"b"	[0 0 1]	"#0000FF"
"cyan"	"c"	[0 1 1]	"#00FFFF"
"magenta"	"m"	[1 0 1]	"#FF00FF"
"yellow"	"y"	[1 1 0]	"#FFFF00"
"black"	"k"	[0 0 0]	"#000000"
"white"	"w"	[1 1 1]	"#FFFFFF"

Here are the RGB triplets and hexadecimal color codes for the default colors MATLAB^® uses in many types of plots.

RGB Triplet	Hexadecimal Color Code	Appearance
[0 0.4470 0.7410]	"#0072BD"
[0.8500 0.3250 0.0980]	"#D95319"
[0.9290 0.6940 0.1250]	"#EDB120"
[0.4940 0.1840 0.5560]	"#7E2F8E"
[0.4660 0.6740 0.1880]	"#77AC30"
[0.3010 0.7450 0.9330]	"#4DBEEE"
[0.6350 0.0780 0.1840]	"#A2142F"

LineStyle — Line style

"-" (default) | "--" | ":" | "-." | "none"

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

Line Style	Description	Resulting Line
"-"	Solid line
"--"	Dashed line
":"	Dotted line
"-."	Dash-dotted line
"none"	No line	No line

FaceColor — Face color

'flat' (default) | 'interp' | 'none' | 'texturemap' | RGB triplet | hexadecimal color code | 'r' | 'g' | 'b' | ...

Face color, specified as one of the values in this table.

Value	Description
'flat'	Use a different color for each face based on the values in the CData property. First you must specify the CData property as a matrix the same size as ZData. The color value at the first vertex of each face (in the positive x and y directions) determines the color for the entire face. You cannot use this value when the FaceAlpha property is set to 'interp'.
'interp'	Use interpolated coloring for each face based on the values in the CData property. First you must specify the CData property as a matrix the same size as ZData. The color varies across each face by interpolating the color values at the vertices. You cannot use this value when the FaceAlpha property is set to 'flat'.
RGB triplet, hexadecimal color code, or color name	Use the specified color for all the faces. This option does not use the color values in the CData property.
'texturemap'	Transform the color data in CData so that it conforms to the surface.
'none'	Do not draw the faces.

RGB triplets and hexadecimal color codes are useful for specifying custom colors.

• 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].

• A hexadecimal color code is a character vector or a string scalar that starts with a hash symbol (#) followed by three or six hexadecimal digits, which can range from 0 to F. The values are not case sensitive. Thus, the color codes "#FF8800", "#ff8800", "#F80", and "#f80" are equivalent.

Alternatively, you can specify some common colors by name. This table lists the named color options, the equivalent RGB triplets, and hexadecimal color codes.

Color Name	Short Name	RGB Triplet	Hexadecimal Color Code	Appearance
"red"	"r"	[1 0 0]	"#FF0000"
"green"	"g"	[0 1 0]	"#00FF00"
"blue"	"b"	[0 0 1]	"#0000FF"
"cyan"	"c"	[0 1 1]	"#00FFFF"
"magenta"	"m"	[1 0 1]	"#FF00FF"
"yellow"	"y"	[1 1 0]	"#FFFF00"
"black"	"k"	[0 0 0]	"#000000"
"white"	"w"	[1 1 1]	"#FFFFFF"

Here are the RGB triplets and hexadecimal color codes for the default colors MATLAB uses in many types of plots.

RGB Triplet	Hexadecimal Color Code	Appearance
[0 0.4470 0.7410]	"#0072BD"
[0.8500 0.3250 0.0980]	"#D95319"
[0.9290 0.6940 0.1250]	"#EDB120"
[0.4940 0.1840 0.5560]	"#7E2F8E"
[0.4660 0.6740 0.1880]	"#77AC30"
[0.3010 0.7450 0.9330]	"#4DBEEE"
[0.6350 0.0780 0.1840]	"#A2142F"

FaceAlpha — Face transparency

1 (default) | scalar in range [0,1] | 'flat' | 'interp' | 'texturemap'

Face transparency, specified as one of these values:

• Scalar in range [0,1] — Use uniform transparency across all the faces. A value of 1 is fully opaque and 0 is completely transparent. Values between 0 and 1 are semitransparent. This option does not use the transparency values in the AlphaData property.

• 'flat' — Use a different transparency for each face based on the values in the AlphaData property. The transparency value at the first vertex determines the transparency for the entire face. First you must specify the AlphaData property as a matrix the same size as the ZData property. The FaceColor property also must be set to 'flat'.

• 'interp' — Use interpolated transparency for each face based on the values in AlphaData property. The transparency varies across each face by interpolating the values at the vertices. First you must specify the AlphaData property as a matrix the same size as the ZData property. The FaceColor property also must be set to 'interp'.

• 'texturemap' — Transform the data in AlphaData so that it conforms to the surface.

FaceLighting — Effect of light objects on faces

'flat' | 'gouraud' | 'none'

Effect of light objects on faces, specified as one of these values:

• 'flat' — Apply light uniformly across each face. Use this value to view faceted objects.

• 'gouraud' — Vary the light across the faces. Calculate the light at the vertices and then linearly interpolate the light across the faces. Use this value to view curved surfaces.

• 'none' — Do not apply light from light objects to the faces.

To add a light object to the axes, use the light function.

Note

The 'phong' value has been removed. Use 'gouraud' instead.

Extended Capabilities

GPU Arrays

Accelerate code by running on a graphics processing unit (GPU) using Parallel Computing Toolbox™.

The surfc function supports GPU array input with these usage notes and limitations:

• This function accepts GPU arrays, but does not run on a GPU.

For more information, see Run MATLAB Functions on a GPU (Parallel Computing Toolbox).

Distributed Arrays

Partition large arrays across the combined memory of your cluster using Parallel Computing Toolbox™.

Usage notes and limitations:

• This function operates on distributed arrays, but executes in the client MATLAB.

For more information, see Run MATLAB Functions with Distributed Arrays (Parallel Computing Toolbox).

Version History

Introduced before R2006a