diff -r 88a01948450d -r d33698326409 plotting_data.rst --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/plotting_data.rst Wed Dec 01 16:51:35 2010 +0530 @@ -0,0 +1,137 @@ +Plotting Experimental Data +============================= +Hello and welcome , this tutorial on Plotting Experimental data is +presented by the fossee team. + +{{{ Show the slide containing title }}} + + +{{{ Show the Outline Slide }}} + +Here we will discuss plotting Experimental data. + +1.We will see how we can represent a sequence of numbers in Python. + +2.We will also become fimiliar with elementwise squaring of such a +sequence. + +3. We will also see how we can use our graph to indicate Error. + +One needs to be fimiliar with the concepts of plotting +mathematical functions in Python. + +We will use data from a Simple Pendulum Experiment to illustrate our +points. + +{{{ Simple Pendulum data Slide }}} + + + + +As we know for a simple pendulum length,L is directly proportional to +the square of time,T. We shall be plotting L and T^2 values. + + +First we will have to initiate L and T values. We initiate them as sequence +of values. To tell ipython a sequence of values we write the sequence in +comma seperated values inside two square brackets. This is also called List +so to create two sequences + +L,t type in ipython shell. :: + + In []: L = [0.1, 0.2, 0.3, 0.4, 0.5,0.6, 0.7, 0.8, 0.9] + + In []: t= [0.69, 0.90, 1.19,1.30, 1.47, 1.58, 1.77, 1.83, 1.94] + + + +To obtain the square of sequence t we will use the function square +with argument t.This is saved into the variable tsquare.:: + + In []: tsquare=square(t) + + array([ 0.4761, 0.81 , 1.4161, 1.69 , 2.1609, 2.4964, 3.1329, + 3.3489, 3.7636]) + + +Now to plot L vs T^2 we will simply type :: + + In []: plot(L,t,.) + +'.' here represents to plot use small dots for the point. :: + + In []: clf() + +You can also specify 'o' for big dots.:: + + In []: plot(L,t,o) + + In []: clf() + + +{{{ Slide with Error data included }}} + + +Now we shall try and take into account error into our plots . The +Error values for L and T are on your screen.We shall again intialize +the sequence values in the same manner as we did for L and t :: + + In []: delta_L= [0.08,0.09,0.07,0.05,0.06,0.00,0.06,0.06,0.01] + + In []: delta_T= [0.04,0.08,0.11,0.05,0.03,0.03,0.01,0.07,0.01] + + + +Now to plot L vs T^2 with an error bar we use the function errorbar() + +The syntax of the command is as given on the screen. :: + + + In []: errorbar(L,tsquare,xerr=delta_L, yerr=delta_T, fmt='b.') + +This gives a plot with error bar for x and y axis. The dots are of +blue color. + + +similarly we can draw the same error bar with big red dots just change +the parameters to fmt to 'ro'. :: + + In []: clf() + In []: errorbar(L,tsquare,xerr=delta_L, yerr=delta_T, fmt='ro') + + + +thats it. you can explore other options to errorbar using the documentation +of errorbar.:: + + In []: errorbar? + + +{{{ Summary Slides }}} + +In this tutorial we have learnt : + +1. How to declare a sequence of number , specifically the kind of sequence we learned was a list. + +2. Plotting experimental data extending our knowledge from mathematical functions. + +3. The various options available for plotting dots instead of lines. + +4. Plotting experimental data such that we can also represent error. We did this using the errorbar() function. + + + {{{ Show the "sponsored by FOSSEE" slide }}} + + + +This tutorial was created as a part of FOSSEE project. + +Hope you have enjoyed and found it useful. + + Thankyou + + + +Author : Amit Sethi +Internal Reviewer : +Internal Reviewer 2 :