# 3.2 Java1492-plotting large quantities of data using java  (Page 18/27)

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## Draw the horizontal axes

The code in Listing 23 draws a set of horizontal axes on the MyCanvas object, one for each trace that will be plotted on the object. These horizontalaxes are shown in Figure 1 and Figure 5 .

## Plot the points

Listing 24 shows the beginning of the code that is used to plot the data values stored in the array that was created in Listing 22 .

Listing 24. Beginning of code to plot the points.
```if(sampleCounter>0){ for(int cnt = 0;cnt<= sampleCounter; cnt++){//Compute a vertical offset int yOffset =(1 + cnt*(sampSpacing + 1)/ this.getWidth())*traceSpacing;```

Listing 24 begins by testing the value of the sample counter to make certain that there are some points to be plotted. If so, it enters a for loop to plot each data value stored in the array. Because it uses the value ofthe sample counter to terminate the for loop, only those data values that have been stored in the array object will be plotted, even if thearray object isn't full.

## A vertical offset

The data values in the array are to be plotted on one or more horizontal axeson the page. Therefore, it is necessary to first determine where on the page each data value is to be plotted. The code in Listing 24 uses various pieces of information to determine the vertical location of the axis against which eachdata value will be plotted.

## Draw an oval

The code in Listing 25 draws an oval centered on the sample value to mark the sample on the plot. It is best if the dimensions of the oval are evenlydivisible by 2 for centering purposes. Otherwise, the ovals may appear to be a little off center.

Listing 25. Draw an oval.
```g.drawOval(cnt*(sampSpacing + 1)% this.getWidth() - ovalWidth/2,yOffset - (int)data[cnt] - ovalHeight/2,ovalWidth, ovalHeight);```

## Is positive vertical up or down?

Normally vertical coordinates increase going down the screen in Java graphics. However, this isn't what most of us are accustomed to seeing when weplot data. We prefer to see increasing vertical coordinates going up the page. The code in Listing 25 reverses the sign on the data values to cause positive data values to be plotted above the axis and negative data values to be plottedbelow the axis. Increasing values go up. Decreasing values go down.

## Connect the points with straight lines

The code in Listing 26 connects the sample values with straight lines. Care is taken to avoid drawing a line from the last sample value on one trace to thefirst sample value on the next trace. That would really be ugly.

Listing 26. Connect the points with straight lines.
```if(cnt*(sampSpacing + 1)% this.getWidth()>= sampSpacing + 1){g.drawLine( (cnt - 1)*(sampSpacing + 1)%this.getWidth(), yOffset - (int)data[cnt-1], cnt*(sampSpacing + 1)%this.getWidth(), yOffset - (int)data[cnt]); }//end if}//end for loop }//end if for sampleCounter>0 }//end overridden paint method}//end inner class MyCanvas }//end inner class Page}//end class PlotALot01```

#### Questions & Answers

how do they get the third part x = (32)5/4
can someone help me with some logarithmic and exponential equations.
sure. what is your question?
20/(×-6^2)
Salomon
okay, so you have 6 raised to the power of 2. what is that part of your answer
I don't understand what the A with approx sign and the boxed x mean
it think it's written 20/(X-6)^2 so it's 20 divided by X-6 squared
Salomon
I'm not sure why it wrote it the other way
Salomon
I got X =-6
Salomon
ok. so take the square root of both sides, now you have plus or minus the square root of 20= x-6
oops. ignore that.
so you not have an equal sign anywhere in the original equation?
Commplementary angles
hello
Sherica
im all ears I need to learn
Sherica
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Tamia
hii
Uday
what is a good calculator for all algebra; would a Casio fx 260 work with all algebra equations? please name the cheapest, thanks.
a perfect square v²+2v+_
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algebra 2 Inequalities:If equation 2 = 0 it is an open set?
or infinite solutions?
Kim
The answer is neither. The function, 2 = 0 cannot exist. Hence, the function is undefined.
Al
y=10×
if |A| not equal to 0 and order of A is n prove that adj (adj A = |A|
rolling four fair dice and getting an even number an all four dice
Kristine 2*2*2=8
Differences Between Laspeyres and Paasche Indices
No. 7x -4y is simplified from 4x + (3y + 3x) -7y
is it 3×y ?
J, combine like terms 7x-4y
how do you translate this in Algebraic Expressions
Need to simplify the expresin. 3/7 (x+y)-1/7 (x-1)=
. After 3 months on a diet, Lisa had lost 12% of her original weight. She lost 21 pounds. What was Lisa's original weight?
what's the easiest and fastest way to the synthesize AgNP?
China
Cied
types of nano material
I start with an easy one. carbon nanotubes woven into a long filament like a string
Porter
many many of nanotubes
Porter
what is the k.e before it land
Yasmin
what is the function of carbon nanotubes?
Cesar
I'm interested in nanotube
Uday
what is nanomaterials​ and their applications of sensors.
what is nano technology
what is system testing?
preparation of nanomaterial
Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
what is system testing
what is the application of nanotechnology?
Stotaw
In this morden time nanotechnology used in many field . 1-Electronics-manufacturad IC ,RAM,MRAM,solar panel etc 2-Helth and Medical-Nanomedicine,Drug Dilivery for cancer treatment etc 3- Atomobile -MEMS, Coating on car etc. and may other field for details you can check at Google
Azam
anybody can imagine what will be happen after 100 years from now in nano tech world
Prasenjit
after 100 year this will be not nanotechnology maybe this technology name will be change . maybe aftet 100 year . we work on electron lable practically about its properties and behaviour by the different instruments
Azam
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
Prasenjit
how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?
Damian
silver nanoparticles could handle the job?
Damian
not now but maybe in future only AgNP maybe any other nanomaterials
Azam
Hello
Uday
I'm interested in Nanotube
Uday
this technology will not going on for the long time , so I'm thinking about femtotechnology 10^-15
Prasenjit
can nanotechnology change the direction of the face of the world
At high concentrations (>0.01 M), the relation between absorptivity coefficient and absorbance is no longer linear. This is due to the electrostatic interactions between the quantum dots in close proximity. If the concentration of the solution is high, another effect that is seen is the scattering of light from the large number of quantum dots. This assumption only works at low concentrations of the analyte. Presence of stray light.
the Beer law works very well for dilute solutions but fails for very high concentrations. why?
how did you get the value of 2000N.What calculations are needed to arrive at it
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