area (MATLAB Functions)

Filled area 2-D plot

Syntax

area(Y)
area(X,Y)
area(...,basevalue)
area(...,'PropertyName',PropertyValue,...)
area(axes_handle,...)
h = area(...)
area('v6',...)

Description

An area graph displays elements in Y as one or more curves and fills the area beneath each curve. When Y is a matrix, the curves are stacked showing the relative contribution of each row element to the total height of the curve at each x interval.

area(Y) plots the vector Y or the sum of each column in matrix Y. The x-axis automatically scales to 1:size(Y,1).

area(X,Y) For vectors X and Y, area(X,Y) is the same as plot(X,Y) except that the area between 0 and Y is filled. When Y is a matrix, area(X,Y) plots the columns of Y as filled areas. For each X, the net result is the sum of corresponding values from the columns of Y.

If X is a vector, length(X) must equal length(Y) and X must be monotonic. If X is a matrix, size(X) must equal size(Y) and each column of X must be monotonic. To make a vector or matrix monotonic, use sort.

area(...,basevalue) specifies the base value for the area fill. The default basevalue is 0. See the BaseValue property for more information.

area(...,'PropertyName',PropertyValue,...) specifies property name and property value pairs for the patch graphics object created by area.

area(axes_handles,...) plots into the axes with handle axes_handle instead of the current axes (gca).

h = area(...) returns handles of areaseries graphics objects.

Backward Compatible Version

hpatches = area('v6',...) returns the handles of patch objects instead of areaseries objects for compatibility with MATLAB 6.5 and earlier. See patch object properties for a discussion of the properties you can set to control the appearance of these area graphs.

See Plot Objects and Backward Compatibility for more information.

Areaseries Objects

Creating an area graph of an m-by-n matrix creates n areaseries objects (i.e., one per column), whereas a 1-by-n vector creates one area object.

Note that some areaseries object properties that you set on an individual areaseries object set the value for all areaseries objects in the graph. See the property descriptions for information on specific properties.

Examples

Stacked Area Graph

This example plots the data in the variable Y as an area graph. Each subsequent column of Y is stacked on top of the previous data. Note that the figure colormap controls the coloring of the individual areas. You can explicitly set the color of an area using the EdgeColor and FaceColor properties.

Y = [1, 5, 3;
    3, 2, 7;
    1, 5, 3;
    2, 6, 1];
area(Y)
grid on
colormap summer
set(gca,'Layer','top')
title 'Stacked Area Plot'

Adjusting the Base Value

The area function uses a y-axis value of 0 as the base of the filled areas. You can change this value by setting the area BaseValue property. For example, negate one of the values of Y from the previous example and replot the data.

Y(3,1) = -1; % Was 1
h = area(Y);
set(gca,'Layer','top')
grid on
colormap summer

The area graph now looks like this:

Adjusting the BaseValue property improves the appearance of the graph:

```
set(h,'BaseValue',-2)
```

Note that setting the BaseValue property on one areaseries object sets the values of all objects.

Specifying Colors and Line Styles

You can specify the colors of the filled areas and the type of lines used to separate them.

h = area(Y,-2); % Set BaseValue via argument
set(h(1),'FaceColor',[.5 0 0])
set(h(2),'FaceColor',[.7 0 0])
set(h(3),'FaceColor',[1 0 0])
set(h,'LineStyle',':','LineWidth',2) % Set all to same value

See Also

bar, plot, sort

Area, Bar, and Pie Plots for related functions

Area Graphs for more examples

Areaseries Properties for property descriptions

any Areaseries Properties