PlotWithMatlab - Dr Dobbs Howto Create a scatter plot in...

Dr. Dobbs’ Howto: Create a scatter plot in Matlab
This howto document walks you through the creation of an x-y scatter plot, and drawing a line
through it in Matlab.
1. Open matlab. Start Æ All Programs Æ Matlab Æ Matlab.
2. Let’s create some a vector of x-data with 8 points from 1 to 8. For the x-data we use the
notation [1:1:8] , where 1 to 8 is the range for the data, and 1 is the interval
>> x= [1:1:8]
x =
1 2 3 4 5 6 7 8
3. and the y-data:
>> y = [4.81,7.72,8.41,13.18,12.86,15.11,18.06,19.05]
4. And let’s plot it the simplest way possible
>> plot(x,y)
hmm, that’s ugly, and isn’t the type of scatter plot we were after. Matlab has joined the
points with straight blue lines by default. Let’s look up some options for the plot
command in Matlab Æ help Æ index Æ “plot”, and to draw plot dots for each data-point.
>> plot(x,y,'.','MarkerSize',20,'MarkerEdgeColor','black')

This looks much better.
5. Now let’s add a grid to the plot and label the axes
grid
xlabel('Time [seconds]')
ylabel('distance [meters]')
6. Method 1 (Simple, but not very powerful): Now let’s superimpose a line yy = 2xx + 3.