Lecture note Data visualization - Chapter 23

This chapter presents the following content: Chapter 5 “plotting”, two dimensional plots, simple x-y plots, titles, labels and grids, multiple plots, plots with more than one line, plots of complex arrays, line, color and mark style, axis scaling and annotating plots,...
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Lecture note Data visualization - Chapter 23Lecture23RecapChapter5“Plotting”TwoDimensionalPlotsSimplexyPlotsTitles,LabelsandGridsMultiplePlotsPlotswithMorethanOneLineAplotwithmorethanonelinecanbecreatedinseveral waysBydefault,theexecutionofasecondplotstatementwill erasethefirstplotHowever,youcanlayerplotsontopofoneanotherby usingtheholdoncommandExecutethefollowingstatementstocreateaplotwith bothfunctionsplottedonthesamegraph x=0:pi/100:2*pi; y1=cos(x*4); plot(x,y1)TheholdoncommandcanbeusedtolayerplotsonsamegraphContinued….Semicolonsareoptionalonboththeplotstatementand theholdonstatementMATLABwillcontinuetolayertheplotsuntilthehold offcommandisexecuted: holdoffAnotherwaytocreateagraphwithmultiplelinesisto requestbothlinesinasingleplotcommandMATLABinterpretstheinputtoplotasalternatingxand yvectors,asin plot(X1,Y1,X2,Y2)Continued….Iftheplotfunctioniscalledwithasinglematrix argument,MATLABdrawsaseparatelineforeach columnofthematrixThexaxisislabeledwiththerowindexvector,1:k, wherekisthenumberofrowsinthematrix.This producesanevenlyspacedplot,sometimescalledaline plotIfplotiscalledwithtwoarguments,oneavectorandthe otheramatrix,MATLABsuccessivelyplotsalinefor eachrowinthematrixForexample:wecancombiney1andy2intoasingleContinued….Here’sanothermorecomplicatedexample: X=0:pi/100:2*pi; Y1=cos(X)*2; Y2=cos(X)*3; Y3=cos(X)*4; Y4=cos(X)*5; Z=[Y1;Y2;Y3;Y4]; plot(X,Y1,X,Y2,X,Y3,X,Y4)ThiscodeproducesthesameresultasMultiplePlotsonSameGraphContinued….Afunctionoftwovariables,thepeaksfunctionproduces sampledatathatareusefulfordemonstratingcertain graphingfunctionsCallingpeakswithasingleargumentnwillcreateannxn matrixWecanusepeakstodemonstratethepowerofusinga matrixargumentintheplotfunctionThecommand plot(peaks(100))resultsintheimpressivegraphThepeakFunction,plottedwithsingleaugmentinplotCommandPlotsofComplexArraysIftheinputtotheplotcommandisasinglearrayof complexnumbers,MATLABplotstherealcomponenton thexaxisandtheimaginarycomponentontheyaxisForexample:if A=[0+0i,1+2i,2+5i,3+4i]then plot(A) title(PlotofaSingleComplexArray) xlabel(RealComponent)Continued….Ifweattempttousetwoarraysofcomplexnumbersinthe plotfunction,theimaginarycomponentsareignoredTherealportionofthefirstarrayisusedforthexvalues, andtherealportionofthesecondarrayisusedforthey– valuesToillustrate,firstcreateanotherarraycalledBbytaking thesineofthecomplexarrayA: B=sin(A)returns B=03.1658+1.9596i67.478930.8794i3.853727.0168iLine,ColorandMarkStyleTheappearanceofplotscanbechangedbyselectinguser definedlinestylesandlinecolorsandbychoosingto showthedatapointsonthegraphwithuserspecified markstylesThecommand helpplotreturnsalistoftheavailableoptionsContinued….Thefollowingcommandsillustratetheuseofline,color, andmarkstyles: x=[1:10]; y=[58.5,63.8,64.2,67.3,71.5,88.3,90.1,90.6, 89.5,90.4]; plot(x,y,:ok)Theresultingplot(showninnextslide)consistsofa dashedline,togetherwithdatapointsmarkedwithcirclesContinued….Tospecifyline,mark,andcolorstylesformultiplelines, addastringcontainingthechoicesaftereachpairofdata pointsIfthestringisnotincluded,thedefaultsareusedForexample: plot(x,y,:ok,x,y*2,xr,x,y/2,b)resultsinthegraphshowninnextslide