Graphics

Area Graphs

The area function displays curves generated from a vector or from separate columns in a matrix. area plots the values in each column of a matrix as a separate curve and fills the area between the curve and the x-axis.

Area Graphs Showing Contributing Amounts

Area graphs are useful for showing how elements in a vector or matrix contribute to the sum of all elements at a particular x location. By default, area accumulates all values from each row in a matrix and creates a curve from those values.

Using this matrix,

• Y = [5 1 2
       8 3 7
       9 6 8
       5 5 5
       4 2 3];
  

the statement,

• area(Y)
  

displays a graph containing three area graphs, one per column.

The height of the area graph is the sum of the elements in each row. Each successive curve uses the preceding curve as its base.

Displaying the Grid on Top.   To display the grid lines in the foreground of the area graph and display only five grid lines along the x-axis, use the statements

• set(gca,'Layer','top')
  set(gca,'XTick',1:5)
  

Overlaying Plots on Bar Graphs

Comparing Datasets with Area Graphs