R help - Mar 2007 - Identifying points in a plot that have duplicate values

I have code like this: - 

#-----------------------------------------------------------------------
------------------------------------------------------

x=scan()
0 0 0 0 0 1 2 3 4

y=scan()
1 1 1 2 2 1 3 4 5

plot(x,y)

identify(0,1,3) #Allows me to select manually to identify co-ordinate
(0,1) as being duplicated 3 times
identify(0,2,2) #Allows me to select manually to identify co-ordinate
(0,2) as being duplicated 2 times
#-----------------------------------------------------------------------
------------------------------------------------------

Is there not a way I can automatically display if points are duplicated
and by how many times?

I thought if I 'jittered' the points ever so slightly I could get an
idea of how many duplicates there are but with >100 points the graph
looks very messy.

Regards
DaveL








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David Lloyd wrote:
> I have code like this: - 
> 
> #-----------------------------------------------------------------------
> ------------------------------------------------------
> 
> x=scan()
> 0 0 0 0 0 1 2 3 4
> 
> y=scan()
> 1 1 1 2 2 1 3 4 5
> 
> plot(x,y)
> 
> identify(0,1,3) #Allows me to select manually to identify co-ordinate
> (0,1) as being duplicated 3 times
> identify(0,2,2) #Allows me to select manually to identify co-ordinate
> (0,2) as being duplicated 2 times
> #-----------------------------------------------------------------------
> ------------------------------------------------------
> 
> Is there not a way I can automatically display if points are duplicated
> and by how many times?
> 
> I thought if I 'jittered' the points ever so slightly I could get
an
> idea of how many duplicates there are but with >100 points the graph
> looks very messy.
  You might consider using alpha transparency - the more times a point
is duplicated the darker it will be.  For example:

df <- data.frame(x=c(0, 0, 0, 0, 0, 1, 2, 3, 4),
                 y=c(1, 1, 1, 2, 2, 1, 3, 4, 5))

pdf("alphaExample.pdf", version = "1.4", width = 6, height =
6)

with(df, plot(x,y, col=rgb(1,0,0,.3), pch=16))

dev.off()

RSiteSearch("alpha transparency")
> Regards
> DaveL
> 
> 
> 
> 
> 
> 
> 
> 
> Click for free info on getting an MBA and make $200K/ year
> 
> 
> 
> 
> Need cash? Click to get a payday loan
> <http://tagline.bidsystem.com/fc/CAaCDCZ60nyjrrOboFeUJgRjigwgNftK/> 
> 
> 
> 
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> ______________________________________________
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> PLEASE do read the posting guide
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-- 
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NDRI, Inc.
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Have a look at ?sunflowerplot, which not only produces a scatterplot
showing multiple points with the same coordinates using special
symbols, but will also produce a list showing the number of points at
each coordinate as well.

On 05/03/07, David Lloyd <DavidLloyd at mail2lloyd.com>
wrote:
> I have code like this: -
>
> #-----------------------------------------------------------------------
> ------------------------------------------------------
>
> x=scan()
> 0 0 0 0 0 1 2 3 4
>
> y=scan()
> 1 1 1 2 2 1 3 4 5
>
> plot(x,y)
>
> identify(0,1,3) #Allows me to select manually to identify co-ordinate
> (0,1) as being duplicated 3 times
> identify(0,2,2) #Allows me to select manually to identify co-ordinate
> (0,2) as being duplicated 2 times
> #-----------------------------------------------------------------------
> ------------------------------------------------------
>
> Is there not a way I can automatically display if points are duplicated
> and by how many times?
>
> I thought if I 'jittered' the points ever so slightly I could get
an
> idea of how many duplicates there are but with >100 points the graph
> looks very messy.
>
> Regards
> DaveL
>
>
>
>
>
>
>
>
> Click for free info on getting an MBA and make $200K/ year
>
>
>
>
> Need cash? Click to get a payday loan
> <http://tagline.bidsystem.com/fc/CAaCDCZ60nyjrrOboFeUJgRjigwgNftK/>
>
>
>
> <span id=m2wTl><p><font face="Arial, Helvetica,
sans-serif" size="2"
style="font-size:13.5px">_______________________________________________________________<BR>Get
the Free email that has everyone talking at <a href=http://www.mail2world.com
target=new>http://www.mail2world.com</a><br>  <font
color=#999999>Unlimited Email Storage &#150; POP3 &#150; Calendar
&#150; SMS &#150; Translator &#150; Much
More!</font></font></span>
>         [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>

-- 
================================David Barron
Said Business School
University of Oxford
Park End Street
Oxford OX1 1HP

David Lloyd wrote:
> I have code like this: - 
> 
> #-----------------------------------------------------------------------
> ------------------------------------------------------
> 
> x=scan()
> 0 0 0 0 0 1 2 3 4
> 
> y=scan()
> 1 1 1 2 2 1 3 4 5
> 
> plot(x,y)
> 
> identify(0,1,3) #Allows me to select manually to identify co-ordinate
> (0,1) as being duplicated 3 times
> identify(0,2,2) #Allows me to select manually to identify co-ordinate
> (0,2) as being duplicated 2 times
> #-----------------------------------------------------------------------
> ------------------------------------------------------
> 
> Is there not a way I can automatically display if points are duplicated
> and by how many times?
> 
> I thought if I 'jittered' the points ever so slightly I could get
an
> idea of how many duplicates there are but with >100 points the graph
> looks very messy.
> 
Hi David.
In the plotrix package there are a few functions that might be helpful.

cluster.overplot - moves ovelying points into a small cluster up to 9
count.overplot - displays the number of overlying points
sizeplot - displays symbols with size relative to the number of points

Jim

Use the iplots package.  The interactive querying works effectively  
for largish datasets (over 50,000 cases) where sunflower plots may not.

Antony Unwin

Professor of Computer-Oriented Statistics and Data Analysis,
University of Augsburg,
86135 Augsburg, Germany
Tel: + 49 821 5982218
http://stats.math.uni-augsburg.de/



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