R help - Feb 2009 - Using color and plotting characters in a scatterplot matrix [Newbie Help]

Hello guys, 

I have this data set that I imported into R using a line: This data set
consists of 7 columns. The two important columns are the first one called
'thrust' and the last one called 'amtemp'. 

jet<-read.table("jetthrust.txt", fill=T, head=T)

I am making a scatterplot matrix simply using the line "pairs(jet)"

The problem is that in the last column of this file which has a header name
'amtemp' I want to sort out 
the values. I want values:

Under 90: To be called low values
In between 90 and 100: To be called medium values
Larger than 100: To be called high values

Then I want those groups of values to be in different colors and different
characters on the scatterplot!

I tried many ways, And I think I am stuck. I first tried it on a normal plot
using the line. 

plot(thrust~amtemp,jet, subset=(jet$amtemp<90), col=1, pch=11)
plot(thrust~amtemp,jet, subset=(jet$amtemp<100), col=2, pch=12)
plot(thrust~amtemp,jet, subset=(jet$amtemp>100), col=3, pch=13)

It didnt work because it just took the last plot and overwrite it over the
last one :(

Someone help please. 

Thanks in advance. 


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I figured out how to do the rest, the only thing I need to do now is to
somehow change the numbers which are < 90 to a character string
"low" . The
values which are between 100 - 90 to convert to character string
"medium".
And the values larger than 100 to convert to character string "high".
Then I
would use this line. 

plot(thrust~amtemp, jet, col=as.numeric(jet$amtemp),
pch=as.numeric(jet$amtemp))

The thing is that I dont know how to convert those numerical values into
"low" "medium" and "high" 

Hmm, but then when I think about it better if its changed to the strings
above, it wont remember the exact numerical value. 

Basically what I want to do is make a scatterplot and then just change the
color and the symbol of those 3 groups so they can be distinguished on the
graph.
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First make a factor with the levels.

jet$Classes <- factor(ifelse(jet$amtemp < 90, "low",
ifelse(jet$amtemp <
100, "medium", "high")))

Then make life easier and use ggplot

install.packages("ggplot2")
library("ggplot2")
ggplot(jet, aes(x = amtemp, y = thrust, colour = Classes)) +
geom_point()

HTH,

Thierry

------------------------------------------------------------------------
----
ir. Thierry Onkelinx
Instituut voor natuur- en bosonderzoek / Research Institute for Nature
and Forest
Cel biometrie, methodologie en kwaliteitszorg / Section biometrics,
methodology and quality assurance
Gaverstraat 4
9500 Geraardsbergen
Belgium 
tel. + 32 54/436 185
Thierry.Onkelinx at inbo.be 
www.inbo.be 

To call in the statistician after the experiment is done may be no more
than asking him to perform a post-mortem examination: he may be able to
say what the experiment died of.
~ Sir Ronald Aylmer Fisher

The plural of anecdote is not data.
~ Roger Brinner

The combination of some data and an aching desire for an answer does not
ensure that a reasonable answer can be extracted from a given body of
data.
~ John Tukey

-----Oorspronkelijk bericht-----
Van: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org]
Namens pfc_ivan
Verzonden: woensdag 4 februari 2009 8:59
Aan: r-help at r-project.org
Onderwerp: Re: [R] Using color and plotting characters in a scatterplot
matrix [Newbie Help]


I figured out how to do the rest, the only thing I need to do now is to
somehow change the numbers which are < 90 to a character string
"low" .
The
values which are between 100 - 90 to convert to character string
"medium".
And the values larger than 100 to convert to character string "high".
Then I
would use this line. 

plot(thrust~amtemp, jet, col=as.numeric(jet$amtemp),
pch=as.numeric(jet$amtemp))

The thing is that I dont know how to convert those numerical values into
"low" "medium" and "high" 

Hmm, but then when I think about it better if its changed to the strings
above, it wont remember the exact numerical value. 

Basically what I want to do is make a scatterplot and then just change
the
color and the symbol of those 3 groups so they can be distinguished on
the
graph.
-- 
View this message in context:
http://www.nabble.com/Using-color-and-plotting-characters-in-a-scatterpl
ot-matrix--Newbie-Help--tp21824880p21825882.html
Sent from the R help mailing list archive at Nabble.com.

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