[R] ggplot2 stat_density2d issue.

[Dmitriy Lyubimov]

Sorry. i forgot the lines with parameters for my multivariate normal
simulation. here's the code for data simulation i used:

=======================
sigm1 <- diag(c(30,50))
sigm2 <- diag(c(5,3))
mu1 <- c(10,15)
mu2 <- c(80,60)

sample <- round(rbind(rmvnorm(100,mu1,sigm1),rmvnorm(100,mu2,sigm2)))
sample <- sample[! (sample[,1] <1 | sample[,2] <1 | sample[,1]> 100 |
sample[,2]>100),]
d <- as.data.frame(sample)
names(d)<-c("x","y")
========================

On Wed, Apr 18, 2012 at 4:46 PM, Dmitriy Lyubimov <dlieu.7 at gmail.com> wrote:
> Thanks David.
>
> let's say sample data (two-modal multivariate normal simulation, needs
> mvtnorm package)
>
> =========================
> library(mvtnorm)
>
> sample <- round(rbind(rmvnorm(100,mu1,sigm1),rmvnorm(100,mu2,sigm2)))
> sample <- sample[! (sample[,1] <1 | sample[,2] <1 | sample[,1]> 100 |
> sample[,2]>100),]
> d <- as.data.frame(sample)
> names(d)<-c("x","y")
> =============
>
> Now suppose we want to create ggplot2 density with this in a specified range
>
> ===============
> library(ggplot2)
> ggplot(d,aes(x,y)) +
>                xlim(0,100)+ylim(0,100)+
>                stat_density2d(bins=4)
> ===============
>
> in my setup (which I believe is latest) i see incomplete contours of
> the area limited by the range of the data. same is true if i switch
> from contours to tile "heatmap" method in the help.
>
> Issue #2. if we can pass kde2d parameters to stat_density2d, as my
> documentation seems to imply, specifying bandwidths doesn't seem to
> make any difference:
>
> +++++++++++++++
> ggplot(d,aes(x,y)) +
>                xlim(0,100)+ylim(0,100)+
>                stat_density2d(bins=4,
>                       h=c(10,10))
>
> +++++++++++++++
>
> Thanks.
> -dmitriy
>
>
>
> On Wed, Apr 18, 2012 at 4:31 PM, David Winsemius <dwinsemius at comcast.net> wrote:
>>
>> On Apr 18, 2012, at 6:55 PM, Dmitriy Lyubimov wrote:
>>
>>> Hello,
>>>
>>> I'd be very grateful for help with some ggplot2's stat_density2d issues.
>>>
>>> First issue is with data limits. xlim() and ylim() doesn't seem to
>>> work; instead, estimates (and plotting) seems to be constrained to
>>> range(x), range(y) no matter what i do. The documentation says i can
>>> pass in kde2d's parameters to ... but pussing kde2d's "lims" parameter
>>> achieves nothing. Contrary to the installed package help, the ggplot2
>>> site reference says that "..." parameters are ignored. So does it or
>>> does it not use kde2d? it seems not, but if not, how do i set the
>>> limit?
>>>
>>> second question was about bandwidth. I want to override that (ideally,
>>> similar to "adjust" parameter to stat::density but in case of kde2d,
>>> "h" parameter would do as well). However, putting h=... doesn't seem
>>> to have any effect, as as i mentioned before, it doesn't seem that
>>> stat_density2d uses kde2d contrary to its doc.
>>>
>>> Could please somebody clarify what stat the ggplot2:: stat_density2d
>>> is using now and how do i adjust bandwidth and limits in the current
>>> version?
>>
>>
>> https://github.com/hadley/ggplot2/blob/master/R/stat-density-2d.r
>>
>> (You might consider reading the Posting Guide. I am not pursuing further
>> because I do not think it is our responsibility to construct test
>> situations.)
>>
>> --
>>
>> David Winsemius, MD
>> West Hartford, CT
>>