R help - Mar 2009 - Unable to run smoother in qplot() or ggplot() - complains about knots

I get the following error when I run qplot()

qplot(grade, read,data = hhm.long.m, geom = c("point",
"smooth"))

Error in smooth.construct.cr.smooth.spec(object, data, knots) :
  x has insufficient unique values to support 10 knots: reduce k.

I am not sure how to tackle this problem. When I take a subsample (<  
1000) than I am able to run that function but with my sample of ~   
40,000 qplot gives me that error. I have 6 grades.
Please cc me on reply.
Thanks!
  Chris

> From: Christopher David Desjardins <cddesjardins at gmail.com>
> To: r-help at r-project.org
> Date: Thu, 12 Mar 2009 17:37:26 -0500
> Subject: [R] Unable to run smoother in qplot() or ggplot() - complains
about knots
> I get the following error when I run qplot()
>
> qplot(grade, read,data = hhm.long.m, geom = c("point",
"smooth"))
>
> Error in smooth.construct.cr.smooth.spec(object, data, knots) :
> x has insufficient unique values to support 10 knots: reduce k.
>
> I am not sure how to tackle this problem. When I take a subsample (<
1000) than I am able to run that function but with my sample of ~ ?40,000 qplot
gives me that error. I have 6 grades.
> Please cc me on reply.
Hi Chris,
Have you read the documentation for stat_smooth? It's not clear to me
what the problem is, because I'm not sure what the defaults are. But
since the default's are not working, I would try it with different
settings. See http://had.co.nz/ggplot2/stat_smooth.html.

-Ista
>
>
> Thanks!
> Chris

On Thu, Mar 12, 2009 at 5:37 PM, Christopher David Desjardins
<cddesjardins at gmail.com> wrote:
> I get the following error when I run qplot()
>
> qplot(grade, read,data = hhm.long.m, geom = c("point",
"smooth"))
>
> Error in smooth.construct.cr.smooth.spec(object, data, knots) :
> ?x has insufficient unique values to support 10 knots: reduce k.
>
> I am not sure how to tackle this problem. When I take a subsample (<
1000)
> than I am able to run that function but with my sample of ~ ?40,000 qplot
> gives me that error. I have 6 grades.
You have 6 values on the x-axis?  Maybe you want to just calculate the
mean at each grade.  If so, see
http://had.co.nz/ggplot2/stat_summary.html

Hadley

-- 
http://had.co.nz/

I am guessing his data is at fixed time points or something similar.

As a "cheat" you can apply a jitter function to the x values and it
should
draw...

g <- ggplot(data, aes(x = jitter(x), y = y,...

J

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