R help - Oct 2007 - scatter plot with 1 standard deviation for each point

Hi,

Could anyone give suggestions how to plot a scatter plot with 1 standard
deviation for each point. To make it clearer, here is a simple example: the
scatterplot is plot(X, Y), but I want to add 1 standard deviation according
to the value of Z for each Y.

X     Y       Z
1     3.5    1.1
.       .       .
.       .       .
.       .       .


Thanks a lot in advance.

FD

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FD wrote:
> Hi,
> 
> Could anyone give suggestions how to plot a scatter plot with 1 standard
> deviation for each point. To make it clearer, here is a simple example: the
> scatterplot is plot(X, Y), but I want to add 1 standard deviation according
> to the value of Z for each Y.
> 
> X     Y       Z
> 1     3.5    1.1
> .       .       .
> .       .       .
> .       .       .
> 
Hi FD,
There are lots of ways to do this (if I understand what you want).

library(plotrix)
# first way
plot(1,3.5)
dispbars(1,3.5,1.1)
# second way
plotCI(1,3.5,1.1)

Another version of plotCI lives in the gplots package.
errbar is in the Hmisc and sfsmisc packages.
plotMeans in the Rcmdr package.
and probably quite a few more.

Jim

> Could anyone give suggestions how to plot a scatter plot with 1 standard
> deviation for each point. To make it clearer, here is a simple example: the
> scatterplot is plot(X, Y), but I want to add 1 standard deviation according
> to the value of Z for each Y.
You can do this with ggplot2 with the following command:

qplot(X, Y, data = df, geom="pointrange", min = Y - Z, max = Y + Z)

You can see a few variations at http://had.co.nz/ggplot2/geom_linerange.html

Hadley


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