## 5. Matlab graphics

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5.1 Plotting (x,y) data

5.2 Axis control

5.3 Plotting (x,y,z) data

5.4 Saving postscript graphs

5.5 Movies

### 5.1 Plotting (x,y) data

Matlab thinks in vectors when plotting (x,y) data.

A single data set with linear scales

>> x = 0:0.1:10; y = sin(x); plot(x,y)

If only one argument is given to plot, the data is equally spaced.

>> plot(cos(x))

A single data set with red *'s marking the data

>> plot(x,y,'r*')

Multiple data sets

>> x = 0:0.1:10; plot(x,sin(x),x,cos(x))

Multiple data sets with different line styles

>> x = 0:0.1:10; plot(x,sin(x),'--',x,cos(x),'.-')

Logarithmic scales are also available. See also loglog and semilogx

>> x = 0:0.1:10; semilogy(x,exp(x))

### 5.2 Axis control

Rescaling is easily accomplished with axis. Simply define a vector
with the minimum and maximums of x and y.

>> x = 0:0.1:10; plot(x,sin(x),x,cos(x))
>> axis([0 2*pi -1 1])

Labeling is also easy. Enclose all labels in single quotes '

>> x = 0:0.1:10; plot(x,sin(x));
>> title('sine'), xlabel('x axis'), ylabel('y axis');

Cut and paste the following commands, then use left mouse click
in the figure window to place the text 'sin(x)'

>> x = 0:0.1:10; plot(x,sin(x));
>> gtext('sin(x)')

### 5.3 Plotting (x,y,z) data

In the following example, a surface plot of the radius is created.

>> [X,Y] = meshgrid(-1:0.1:1,-1:0.1:1);
>> surf(sqrt(X.*X + Y.*Y))

A color plot without elevation can also be easily displayed.

>> pcolor(sqrt(X.*X + Y.*Y))

To smooth the coloring type

>> shading('interp')

And to remove the labeling

>> axis('off')

### 5.4 Saving postscript graphs

To save the current figure as a postscript file to print or import
into another document, type

>> print -dps foo.ps

### 5.5 Movies

*David Eyre*

*9/8/1998*