# Example of Plotting Simple 2D Data

Matlab provides facilities for both reading external data files, and for creating these kinds of plots. Here's a sample data file, simply named 'data':

0.00 0.00 0.10 0.01 0.20 0.04 0.30 0.09 0.40 0.16 0.50 0.25 0.60 0.36 0.70 0.49 0.80 0.64 0.90 0.81 1.00 1.00

It's an ordered sequence of points, with each row containing an x, y combination. All we want to do here is to turn this data into a simple line graph.

To bring this data file into Matlab, you can use the `load`

command:

load -ascii data

Now we have a 11x2 matrix of numbers in a variable named `data`

.
We want to strip out each column into a separate variable:

x=data(:,1)'; % strip out x axis values y=data(:,2)'; % strip out y axis values

The ' operator is a transpose, and transforms the variable from a column of numbers into a row. It's optional, but I think it's easier to read a row of numbers than a column.

Now we have a consistent set of (x,y) data that's ready to be graphed:

plot(x,y) xlabel('x') ylabel('y') zlabel('y = x^2') title('Simple line plot')

The final Matlab program file is shown below:

load -ascii data x=data(:,1)'; % strip out x axis values y=data(:,2)'; % strip out y axis values plot(x,y) xlabel('x') ylabel('y=x^2') title('Simple line data plot')

The final output is shown below: