The use of subplot function in MATLAB

Catalog

grammar

explain

Example

Upper and lower subgraphs

Quadrant of subgraph  

Subgraphs of different sizes

Replace the subgraph with empty coordinate area  

Customize the subgraph on the location  

Create a subgraph containing polar regions  

Modify the coordinate area attribute after creation

Make the subgraph the current coordinate area

Convert existing coordinate areas into subgraphs  

Convert coordinate areas in different drawing windows into subgraphs  

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        subplot The function is to create a coordinate area at each block position .

grammar

subplot(m,n,p)
subplot(m,n,p,'replace')
subplot(m,n,p,'align')
subplot(m,n,p,ax)
subplot('Position',pos)
subplot(___,Name,Value)
ax = subplot(___)
subplot(ax)

explain

subplot(m,n,p) Divide the current window into m×n grid , And in p Create a coordinate area at the specified location .MATLAB Number subgraphs by line number . The first subgraph is the first column of the first row , The second subgraph is the second column of the first row , And so on . If a coordinate zone already exists at the specified location , This command will set the coordinate area as the current coordinate area .

subplot(m,n,p,'replace') Delete location p And create a new coordinate area .

subplot(m,n,p,'align') Create a new coordinate area , To align the borders . This option is the default behavior .

subplot(m,n,p,ax) Set the existing coordinate area ax Convert to sub graph in the same graph window .

subplot('Position',pos) stay pos Create a coordinate area at the specified custom location . Use this option to locate subgraphs that are not aligned with the grid position . Appoint pos As [left bottom width height] Four element vector of form . If the new coordinate area overlaps with the existing coordinate area , The new coordinate area will replace the existing coordinate area .

subplot(___,Name,Value) Use one or more names - Value pair group parameter modify coordinate area attribute . Set the coordinate area properties after all other input parameters .

ax = subplot(___) Create a Axes object 、PolarAxes Object or GeographicAxes object . Can be used later ax Modify the coordinate area .

subplot(ax) take ax The specified coordinate area is set as the current coordinate area of the parent drawing window . If the parent window is not the current window , This option does not make the parent window the current window .

Example

Upper and lower subgraphs

         Create a chart window with two stacked subgraphs . Draw a sine wave on each subgraph .

subplot(2,1,1);
x = linspace(0,10);
y1 = sin(x);
plot(x,y1)

subplot(2,1,2); 
y2 = sin(5*x);
plot(x,y2)

         As shown in the figure ：

Quadrant of subgraph  

         Create a diagram window divided into four subgraphs . Draw a sine wave on each subgraph and assign a title to each subgraph .

subplot(2,2,1)
x = linspace(0,10);
y1 = sin(x);
plot(x,y1)
title('Subplot 1: sin(x)')

subplot(2,2,2)
y2 = sin(2*x);
plot(x,y2)
title('Subplot 2: sin(2x)')

subplot(2,2,3)
y3 = sin(4*x);
plot(x,y3)
title('Subplot 3: sin(4x)')

subplot(2,2,4)
y4 = sin(8*x);
plot(x,y4)
title('Subplot 4: sin(8x)')

         As shown in the figure ：

Subgraphs of different sizes

         Create a diagram window with three subgraphs . Create two subgraphs in the upper part of the diagram window , And create a third sub graph in the lower part of the graph window . Add a title to each subgraph .

subplot(2,2,1);
x = linspace(-3.8,3.8);
y_cos = cos(x);
plot(x,y_cos);
title('Subplot 1: Cosine')

subplot(2,2,2);
y_poly = 1 - x.^2./2 + x.^4./24;
plot(x,y_poly,'g');
title('Subplot 2: Polynomial')

subplot(2,2,[3,4]);
plot(x,y_cos,'b',x,y_poly,'g');
title('Subplot 3 and 4: Both')

         As shown in the figure ：

Replace the subgraph with empty coordinate area  

         Create a chart window containing four needle graphs of random data . Then replace the second sub graph with empty coordinate area . 

for k = 1:4
    data = rand(1,10);
    subplot(2,2,k)
    stem(data)
end

         As shown in the figure ：

subplot(2,2,2,'replace')

          As shown in the figure ：

Customize the subgraph on the location  

         Create a window containing two subgraphs that are not aligned with the grid position . Specify a custom location for each subgraph .

pos1 = [0.1 0.3 0.3 0.3];
subplot('Position',pos1)
y = magic(4);
plot(y)
title('First Subplot')

pos2 = [0.5 0.15 0.4 0.7];
subplot('Position',pos2)
bar(y)
title('Second Subplot')

         As shown in the figure ：

Create a subgraph containing polar regions  

         Create a drawing window with two polar regions . Create a polar chart in the upper subgraph , Create a polar scatter chart in the lower subgraph .

figure
ax1 = subplot(2,1,1,polaraxes);
theta = linspace(0,2*pi,50);
rho = sin(theta).*cos(theta);
polarplot(ax1,theta,rho)

ax2 = subplot(2,1,2,polaraxes);
polarscatter(ax2,theta,rho)

         As shown in the figure ：

Modify the coordinate area attribute after creation

         Create a diagram window with two subgraphs . take Axes Object to a variable ax1 and ax2. take Axes Object is specified as the input of the drawing function , To ensure that the drawing function is drawn in a specific subgraph .

ax1 = subplot(2,1,1);
Z = peaks;
plot(ax1,Z(1:20,:))

ax2 = subplot(2,1,2);  
plot(ax2,Z)

          As shown in the figure ：

         By setting Axes Object to modify the coordinate area . Change the font size of the upper sub graph and the line width of the lower sub graph . Some drawing functions can set coordinate area properties . First execute the drawing function , Then specify the coordinate area attribute to avoid overwriting the setting of the existing coordinate area attribute . Use dot notation to set properties . 

Make the subgraph the current coordinate area

         Create a diagram window with multiple subgraphs . take Axes Objects are stored in vectors ax in . Then make the second sub graph the current coordinate area . Create a line graph and change the axis range of the second sub graph . By default , The graph function acts on the current coordinate area .

for k = 1:4
    ax(k) = subplot(2,2,k);
end

subplot(ax(2))
x = linspace(1,50);
y = sin(x);
plot(x,y,'Color',[0.1, 0.5, 0.1])
title('Second Subplot')
axis([0 50 -1 1])

         As shown in the figure ：

Convert existing coordinate areas into subgraphs  

         Create a line diagram . Then transform the coordinate area , Make it the lower sub graph of the graph window .subplot The function uses the window where the original coordinate area is located .

x = linspace(1,10);
y = sin(x);
plot(x,y)
title('Sine Plot')

         As shown in the figure ：

ax = gca;
subplot(2,1,2,ax)

          As shown in the figure ：

Convert coordinate areas in different drawing windows into subgraphs  

         Merge coordinate areas located in different windows into a single window containing subgraphs .

         Create two diagrams in two different diagram windows . take Axes Object to a variable ax1 and ax2. take Legend Object to a variable lgd.

figure
x = linspace(0,10);
y1 = sin(x);
plot(x,y1)
title('Line Plot 1')

         As shown in the figure ：

ax1 = gca;

figure
y2 = 2*sin(x);
plot(x,y2)
title('Line Plot 2')
lgd = legend('2*Sin(x)');

         As shown in the figure ：

ax2 = gca;

         Use copyobj Create two Axes Copy of object . Specify the parent of the copied coordinate area as the new drawing window . Because the legend and color bar will not be copied with the relevant coordinate area , So please copy the legend with the coordinate area .

fnew = figure;
ax1_copy = copyobj(ax1,fnew);
subplot(2,1,1,ax1_copy)

copies = copyobj([ax2,lgd],fnew);
ax2_copy = copies(1);
subplot(2,1,2,ax2_copy)

         As shown in the figure ：

  Input parameter description

m - Grid rows

         Grid rows , Specify as a positive integer .

n - Number of grid columns

         Number of grid columns , Specify as a positive integer .

p - Grid location of the new coordinate area

Grid location of the new coordinate area , Specify as scalar or positive integer vector .

• If p Is a positive integer scalar , be subplot In grid position p Create a sub graph at .

• If p Is a positive integer vector , be subplot Create a new span p Subgraphs of grid locations listed in .

Example ：subplot(2,3,1) In position 1 Create a sub graph at .

Example ： subplot(2,3,[2,5]) Create cross location 2 and 5 The children of .

Example ： subplot(2,3,[2,6]) Create cross location 2、3、5 and 6 The children of .

pos - Custom location of the new coordinate area

         Custom location of the new coordinate area , Designated as [left bottom width height] Four element vector of form .

• left and bottom Element specifies the position of the lower left corner of the subgraph relative to the lower left corner of the graph window .

• width and height Element specifies the dimension of the subgraph .

         Specify between 0 and 1 Normalized value between （ Based on the inner bound of graph window ）.

         Be careful ： When using scripts to create subgraphs , In a drawnow Order or MATLAB Return to waiting for user command ,MATLAB Will not be finalized Position Property value . Before the script refreshes the drawing or exits , Of subgraphs Position Attribute values will be affected by changes .

ax - To set as the current coordinate area or convert to the existing coordinate area of the subgraph

         To set as the current coordinate area or convert to the existing coordinate area of the subgraph , Designated as Axes object 、PolarAxes object 、GeographicAxes Object or has PositionConstraint Attribute graphic object , Such as HeatmapChart object .

         To create an empty polar or geographic coordinate area at the location of the sub map , Please put ax Designated as polaraxes or geoaxes function . for example ,subplot(2,1,2,polaraxes).

Tips

• To clear the contents of the picture window , Please use clf. for example , You can clear the existing sub drawing layout in the drawing window before creating a new sub drawing layout .

• To superimpose coordinate areas , Please switch to axes command .subplot The function deletes the existing coordinate area that overlaps the new coordinate area . for example ,subplot('Position',[.35 .35 .3 .3]) All the bottom coordinate areas will be deleted , but axes('Position',[.35 .35 .3 .3]) The new coordinate area will be placed in the middle of the drawing window without deleting the bottom coordinate area .

• subplot(111) It's an exception , Its behavior is related to subplot(1,1,1) Different . For backward compatibility reasons ,subplot(111) Is a special case of subgraphs , It does not immediately create coordinate areas , Instead, set the picture window , So that the following graphic commands can be executed clf reset. The next graphic command will delete all the window children , And create a new coordinate area in the default location .subplot(111) No return Axes object , If the code specifies the return parameter , An error will occur .

Alternative functions

        ​ Use  tiledlayout  and  nexttile  Function to create a configurable drawing tile . Configuration options include ：​

• Control of spacing between drawings and around layout edges

• Options for sharing titles at the top of the layout

• share x Axis and y Options for axis labels

• It is used to control whether the partition is fixed size or adjustable variable size