[R] Smoothing z-values according to their x, y positions

[David Winsemius]

"Emmanuel Levy" <emmanuel.levy at gmail.com> wrote in
news:e4654710803191554k4dfc2728g70bde35f41627754 at mail.gmail.com: 

> Dear Bert,
> 
> Thanks for your reply - I indeed saw a lot of functions using:
> help.search("smooth")
> 
> The problem is that most seem to not be very appropriate to what I'd 
> like, or they seem extremely complicated (e.g. gma). I am probably 
> missing something as I don't  see how to use Loess. From my poor 
> understanding, it seems to be for 2D data. Here I want to smooth the
> third "z" component. 
> 
> In the meantime I adapted a function from Greg Warnes, which sort of
> does the job (although the smoothing is not very nice).
> So I'd be very happy to learn how do do something similar with
> loess! 

I am realizing that my memories about the kde2d function were faulty. My 
suggestion would only let you look at the 2-d "marginals". You probably 
want a true 3d plotting function. The densities would then be closed 
surfaces.

Take a look at Feng and Tierney's figure 10 in this poster at:
<http://user2007.org/program/posters/feng.pdf>

The code cannot be cut-and-pasted, but if it does what you want, it would 
be worth it.

-- 
David Winsemius