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Plotting basics.

GraphingWithMATLAB

A picture is worth a thousand words, particularly visual representation of data in engineering is very useful. MATLAB has powerful graphics tools and there is a very helpful section devoted to graphics in MATLAB Help: Graphics. Students are encouraged to study that section; what follows is a brief summary of the main plotting features.

Two-dimensional plots

The plot Statement

Probably the most common method for creating a plot is by issuing plot(x, y) statement where function y is plotted against x.

Type in the following statement at the MATLAB prompt:

x=[-pi:.1:pi]; y=sin(x); plot(x,y);

After we executed the statement above, a plot named Figure1 is generated:

Plot
Graph of sin(x)

Having variables assigned in the Workspace, x and y=sin(x) in our case, we can also select x and y, and right click on the selected variables. This opens a menu from which we choose plot(x,y). See the figure below.

PlotFromWorkspace
Creating a plot from Workspace.

Annotating plots

Graphs without labels are incomplete and labeling elements such as plot title, labels for x and y axes, and legend should be included. Using up arrow, recall the statement above and add the annotation commands as shown below.

x=[-pi:.1:pi];y=sin(x);plot(x,y);title('Graph of y=sin(x)');xlabel('x');ylabel('sin(x)');grid on

Run the file and compare your result with the first one.

sinxLabels
Graph of sin(x) with Labels.

Type in the following at the MATLAB prompt and learn additional commands to annotate plots: help gtext help legendhelp zlabel

Superimposed plots

If you want to merge data from two graphs, rather than create a new graph from scratch, you can superimpose the two using a simple trick:

% This script generates sin(x) and cos(x) plot on the same graph % initialize variablesx=[-pi:.1:pi]; %create a row vector from -pi to +pi with .1 incrementsy0=sin(x); %calculate sine value for each x y1=cos(x); %calculate cosine value for each x% Plot sin(x) and cos(x) on the same graph plot(x,y0,x,y1);title('Graph of sin(x) and cos(x)'); %Title of graph xlabel('x'); %Label of x axisylabel('sin(x), cos(x)'); %Label of y axis legend('sin(x)','cos(x)'); %Insert legend in the same order as y0 and y1 calculatedgrid on %Graph grid is turned

sinxLabelsLegend
Graph of sin(x) and cos(x) in the same plot with labels and legend.

Multiple plots in a figure

Multiple plots in a single figure can be generated with subplot in the Command Window. However, this time we will use the built-in Plot Tools. Before we initialize that tool set, let us create the necessary variables using the following script:

% This script generates sin(x) and cos(x) variables clc %Clears command windowclear all %Clears the variable space close all %Closes all figuresX1=[-2*pi:.1:2*pi]; %Creates a row vector from -2*pi to 2*pi with .1 incrementsY1=sin(X1); %Calculates sine value for each x Y2=cos(X1); %Calculates cosine value for each xY3=Y1+Y2; %Calculates sin(x)+cos(x) Y4=Y1-Y2; %Calculates sin(x)-cos(x)

Questions & Answers

what are the products of Nano chemistry?
Maira Reply
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
learn
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
learn
Google
da
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Bhagvanji
Preparation and Applications of Nanomaterial for Drug Delivery
Hafiz Reply
revolt
da
Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
Jyoti Reply
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
LITNING Reply
what is a peer
LITNING Reply
What is meant by 'nano scale'?
LITNING Reply
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
Hafiz
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
Adin
why?
Adin
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
research.net
kanaga
sciencedirect big data base
Ernesto
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Source:  OpenStax, A brief introduction to engineering computation with matlab. OpenStax CNX. Nov 17, 2015 Download for free at http://legacy.cnx.org/content/col11371/1.11
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