Scilab/C2/Plotting-2D-graphs/English-timed
From Script | Spoken-Tutorial
| Time | Narration | |
| 00.00 | Welcome to the spoken tutorial on Plotting 2D graphs with scilab. | |
| 00.05 | Assuming that Scilab is installed on your computer, we will discuss plots in Scilab. | |
| 00.10 | Scilab offers many ways to create and customize various types of 2D and 3D plots. | |
| 00.16 | The several common charts Scilab can create are: x-y plots, contour plots, 3D plots, histograms, bar charts, etc... | |
| 00.25 | Now open your Scilab console window. | |
| 00.28 | I will use Plotting.sce file to cut and paste the commands. | |
| 00.34 | In order to Plot, we need a set of points. Let us create a sequence of equally spaced points. | |
| 00.40 | This can be done by the linspace command which creates a linearly equally spaced vector. | |
| 00.46 | For Example | |
| 00.49 | x is a row vector with 5 points linearly equally spaced between 1 and 10 | |
| 00.57 | Similarly y is a row vector with linearly equally spaced 5 points between 1 and 20 | |
| 01.08 | More information on linspace command can be obtained from the Help documentation. | |
| 01.14 | We will now plot a graph with the arguments x and y using the Plot function. | |
| 0119 | This is similar to the one used in matlab. Plot x,y | |
| 01.26 | creates a graph of x verses y as you see. | |
| 01.32 | Notice that the graphics window is labeled as '0' We will open another graphic window using the , | |
| 01.39 | xset function. I will close this cut the xset function paste in scilab hit enter. | |
| 01.51 | You will see a graphic window number 1. Note that two arguments are passed to this function namely the window and 1. | |
| 02.03 | The next graph will be plotted on this window. | |
| 02.07 | For scilab plot 2d is the native function used to plot 2d graphs. | |
| 02.14 | plot2d command plots a graph of x verses y as you see. | |
| 02.27 | Notice that there is a third argument called style. | |
| 02.32 | Style argument is optional.It is used to customize the appearance of the plot. | |
| 02.36 | For positive values of style the curve is a plain with different colours like green for 3 in our case. | |
| 02.44 | The default value of style is 1. | |
| 02.46 | Try plotting graphs for negative values and see the difference in appearance yourself. | |
| 02.52 | Also we can set the start points and end points for x and y axis by passing the fourth argument.It is called rect. As you see, | |
| 03.08 | We have x axis starting from 1 to 10 and y axis from 1 to 20. | |
| 03.15 | The order of argument in the rect command is xmin,ymin,xmax and ymax. | |
| 03.25 | Let us now learn about Title,Axis and Legends | |
| 03.28 | To configure labels to the axis and title to the plot we can use the commands title, x label and ylabel. | |
| 03.38 | I will cut this set of commands and paste in the console. Hit enter | |
| 03.45 | You will see that the graph has been labeled x to the x axis, y to the y axis and the title of the graph is my title. | |
| 03.59 | You may want to configure the title and axis of the plot in a single command instead of 3 for this purpose we use the xtitle, | |
| 04.09 | command with all the 3 arguments. | |
| 04.12 | I will cut this command paste in scilab enter. | |
| 04.19 | Now you see that the x axis label is X axis , Y axis and the title is My title. | |
| 04.27 | The clf() function that i am typing now will clear the graphic window as you see. | |
| 04.37 | It is useful while plotting different graph on the same graphic window. | |
| 04.42 | I will close this window. | |
| 04.44 | Sometimes we need to compare two sets of data in the same plot, that is, one set of x data and two sets of y data. | |
| 04.52 | Let us see an example for this I will scroll down | |
| 04.57 | We will define the x axis points in a row vector x using the linspace command | |
| 05.03 | Let us define a function | |
| 05.05 | y1 = x^2 | |
| 05.08 | plot x verses y1 | |
| 05.10 | define another function | |
| 05.12 | y2 = 2*x^2 | |
| 05.15 | plot x verses y2 | |
| 05.19 | we will also give label and title to our graph | |
| 05.23 | Notice that we have additionally passed ”o-” and ”+-” commands to the plot function, to change the appearance of the curve | |
| 05.33 | These arguments are not a part of the plot2d function. | |
| 05.37 | They can be used only with the plot function | |
| 05.41 | I will copy these set of commands and paste in the scilab console. | |
| 05.49 | You see the graph | |
| 05.52 | Wouldn't it be of great help to know which curve is associated with which function? | |
| 05.57 | This can be achieved using the legend command as you see | |
| 06.09 | "o-" curve represents function y1=x^2 and "+-" curve represents function y2=2*x^2 | |
| 06.20 | I will close this graphic window | |
| 06.23 | We will now discuss about plot2d demos and subplot function | |
| 06.28 | Scilab provides demos for all its major functions Demos of plot2d can be viewed through demonstration tab. | |
| 06.40 | click on Graphics,click plot2d_3d plots and select a demo out the various demos provided. I will click on plot2d. | |
| 06.54 | You will see the demo graph | |
| 06.56 | The code for this graph can also be seen by clicking on the view code button here. | |
| 07.02 | This link does not open in Mac OS but works in windows and linux | |
| 07.08 | Nevertheless in Mac the code can be viewed through the directory. | |
| 07.12 | Let us go to the terminal. | |
| 07.16 | currently i am in demos directory of scilab 5.2 as shown. | |
| 07.22 | The full path to this directory is shown here. | |
| 07.28 | we will type ls to see the list of demos available as you see here. | |
| 07.37 | Then we will select the 2d_3d_plots directory and hit enter type ls again to see various demo code available in the sce files | |
| 07.55 | we will view the code for the demo which we have seen earlier. | |
| 08.00 | Type more plot2d.dem.sce and hit enter | |
| 08.12 | Here you will see the code for the demo graph of plot2d function | |
| 08.18 | I will close the terminal I will close the demo graph and the demo window | |
| 08.26 | Similarly you can go through the other demos and explore scilab | |
| 08.30 | Let us now discuss about Subplot function | |
| 08.33 | The subplot() function divides the graphics window into a matrix of sub-windows. | |
| 08.38 | To explain this function we will use demos for plotting 2D graphs in scilab. | |
| 08.43 | For example, type plot 2d in your console and see the demo plot for this function | |
| 08.59 | I will close this window. | |
| 09.01 | The subplot command breaks the graphics window into a 2 by 2 matrix of sub-windows represented by the first two arguments in the subplot command. | |
| 09.11 | The third argument denotes the current window in which the plot will be plotted | |
| 09.16 | I will execute this whole set of commands by copying it to the scilab console | |
| 09.25 | You can see 4 plots in a single plot window . | |
| 09.29 | The plot obtained can be saved as a image on your computer | |
| 09.33 | Click on the graphic window, go to File menu select export to . | |
| 09.40 | Give a suitable title to your plot, select a destination folder to save your file select the file format in which you want your image to appear. | |
| 10.59 | I will select the JPEG format and Click Save. | |
| 10.05 | Browse through the directory to open the image and verify yourself whether it has been saved or not. | |
| 10.12 | This brings us to the end of this spoken tutorial on Plotting in Scilab. | |
| 10.16 | There are many other functions in Scilab which will be covered in other spoken tutorials. | |
| 10.20 | Keep watching the Scilab links. | |
| 10.23 | Spoken Tutorials are part of the Talk to a Teacher project, supported by the National Mission on Education through ICT. | |
| 10.29 | More information on the same is availableon the following link | |
| 10.33 | Thanks for joining. Good bye |
