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