Hi,
May be this helps:
gg <- ggplot(plotdat, aes(x = Age, y = Probability, color = Level)) +
geom_line(size=2.5) + theme_bw() + xlim(10,80) + facet_grid(Sex ~ Treatment, #
scales = "free", labeller = function(x, y) sprintf("%s = %s", x, y) )
plotdat2 <- subset(plotdat,as.character(Improved)==as.character(Level))
gg+geom_point(data= plotdat2, aes(x=Age, y=Probability),color="black",size=1.5)
A.K.
On Wednesday, April 2, 2014 9:22 PM, Michael Friendly <frien...@yorku.ca> wrote:
Thanks, Dennis
Not quite. I need to have the same lines as in the original, using
plotdat, but then
add the points from your plotdat2
gg <- ggplot(plotdat, aes(x = Age, y = Probability, color = Level)) +
geom_line(size=2.5) + theme_bw() + xlim(10,80) +
# geom_point(color="black", size=1.5) + # not these points
facet_grid(Sex ~ Treatment, # scales = "free",
labeller = function(x, y) sprintf("%s = %s", x, y)
)
# want these points, added to the above plot
plotdat2 <- subset(plotdat,
as.character(Improved) == as.character(Level))
On 02/04/2014 7:09 PM, Dennis Murphy wrote:
> Hi Michael:
>
> Does this work?
>
> plotdat2 <- subset(plotdat,
> as.character(Improved) == as.character(Level))
> ggplot(plotdat2, aes(x = Age, y = Probability, color = Level)) +
> geom_line(size=2.5) + theme_bw() + xlim(10,80) +
> geom_point(color="black", size=1.5) +
> facet_grid(Sex ~ Treatment,
> labeller = function(x, y) sprintf("%s = %s", x, y)
> )
>
> Dennis
>
> On Wed, Apr 2, 2014 at 7:43 AM, Michael Friendly <frien...@yorku.ca> wrote:
>> I'm working on an example of plotting predicted probabilities from a
>> proportional odds model.
>> The steps below generate a data frame, plotdat, that I want to plot with
>> ggplot.
>>
>> library(MASS)
>> data("Arthritis", package="vcd")
>> arth.polr <- polr(Improved ~ Sex + Treatment + Age, data=Arthritis,
>> Hess=TRUE)
>>
>> # get predicted probs for categories of Improve
>> arth.fitp <- cbind(Arthritis,
>> predict(arth.polr, type="probs"))
>> head(arth.fitp)
>>
>> # reshape probs to long
>> library(reshape2)
>> plotdat <- melt(arth.fitp,
>> id.vars = c("Sex", "Treatment", "Age", "Improved"),
>> measure.vars=c("None", "Some", "Marked"),
>> variable.name = "Level",
>> value.name = "Probability")
>> ## view first few rows
>> head(plotdat)
>>
>>> head(plotdat)
>> Sex Treatment Age Improved Level Probability
>> 1 Male Treated 27 Some None 0.7326185
>> 2 Male Treated 29 None None 0.7174048
>> 3 Male Treated 30 None None 0.7096042
>> 4 Male Treated 32 Marked None 0.6936286
>> 5 Male Treated 46 Marked None 0.5702499
>> 6 Male Treated 58 Marked None 0.4563432
>>
>> In the plot step, I am plotting Probability vs. Age, stratified by Level,
>> and faceted by
>> Sex and Treatment. My question concerns the use of geom_point().
>> The call below plots 3 points for each case, one on each Level curve.
>>
>>
>> ggplot(plotdat, aes(x = Age, y = Probability, color = Level)) +
>> geom_line(size=2.5) + theme_bw() + xlim(10,80) +
>> geom_point(color="black", size=1.5) +
>> facet_grid(Sex ~ Treatment,
>> labeller = function(x, y) sprintf("%s = %s", x, y)
>> )
>>
>> Instead,
>> I want to plot only one point for each case, for the value of Level that
>> corresponds
>> to the value of Improved in this data set. Somehow, this involves something
>> like an aes() argument to geom_point(), with Level indexed by Improved, or
>> some such.
>> How can I do this?
>>
>> --
>> Michael Friendly Email: friendly AT yorku DOT ca
>> Professor, Psychology Dept. & Chair, Quantitative Methods
>> York University Voice: 416 736-2100 x66249 Fax: 416 736-5814
>> 4700 Keele Street Web: http://www.datavis.ca
>> Toronto, ONT M3J 1P3 CANADA
>>
>> ______________________________________________
>> R-help@r-project.org 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.
--
Michael Friendly Email: friendly AT yorku DOT ca
Professor, Psychology Dept. & Chair, Quantitative Methods
York University Voice: 416 736-2100 x66249 Fax: 416 736-5814
4700 Keele Street Web: http://www.datavis.ca
Toronto, ONT M3J 1P3 CANADA
______________________________________________
R-help@r-project.org 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.
______________________________________________
R-help@r-project.org 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.
