Graphics

Types of Bar Graphs

MATLAB has four specialized functions that display bar graphs. These functions display 2- and 3-D bar graphs, and vertical and horizontal bar graphs.

	Two-Dimensional	Three-Dimensional
Vertical	bar	bar3
Horizontal	barh	bar3h

Grouped Bar Graph

By default, a bar graph represents each element in a matrix as one bar. Bars in a 2-D bar graph, created by the bar function, are distributed along the x-axis with each element in a column drawn at a different location. All elements in a row are clustered around the same location on the x-axis.

For example, define Y as a simple matrix and issue the bar statement in its simplest form.

Y = [5 2 1
     8 7 3
     9 8 6
     5 5 5
     4 3 2];
bar(Y)

The bars are clustered together by rows and evenly distributed along the x-axis.

Detached 3-D Bars

The bar3 function, in its simplest form, draws each element as a separate 3-D block, with the elements of each column distributed along the y-axis. Bars that represent elements in the first column of the matrix are centered at 1 along the x-axis. Bars that represent elements in the last column of the matrix are centered at size(Y,2) along the x-axis. For example,

bar3(Y)

displays five groups of three bars along the y-axis. Notice that larger bars obscure Y(1,2) and Y(1,3).

By default, bar3 draws detached bars. The statement bar3(Y,'detach') has the same effect.

Labeling the Graph.   To add axes labels and x tick marks to this bar graph, use the statements

xlabel('X Axis')
ylabel('Y Axis')
zlabel('Z Axis')
set(gca,'XTick',[1 2 3])

Grouped 3-D Bars

Cluster the bars from each row beside each other by specifying the argument 'group'. For example,

bar3(Y,'group')

groups the bars according to row and distributes the clusters evenly along the y-axis.

Bar and Area Graphs

Stacked Bar Graphs to Show Contributing Amounts