在R中平滑3d图

Question

I made 3d plot in rgl.persp3d but I don't know how to smooth that to see trend. Or maybe next solution is to implement wireframe in rgl.persp3d (because I need this plot to be interactive). Please, help.

library(mgcv)


x<- rnorm(200)
y<- rnorm(200)
z<-rnorm(200)

tab<-data.frame(x,y,z)
tab

#surface wireframe:

mod <- gam(z ~ te(x, y), data = tab)

wyk <- matrix(fitted(mod), ncol = 20) #8 i 10 też ok

wireframe(wyk, drape=TRUE, colorkey=TRUE)

#surface persp3d


library(rgl)
library(akima)


z_interpolation <- 200

tabint <- interp(x, y, z)

x.si <- tabint$x
y.si <- tabint$y
z.si <- tabint$z
nbcol <- 200
vertcol <- cut(t, nbcol)
color = rev(rainbow(nbcol, start = 0/6, end = 4/6))
persp3d(x.si, y.si, z.si, col = color[vertcol], smooth=T)

So wireframe is neither smoothed nor interactive ...and rgl.persp3d is interactive but no smoothed. And I can't have both smoothed and interactive.

Answer 1

rgl just draws what you give it. You need to use mgcv as in your first example to do the smoothing, but you don't get a matrix of fitted values back at the end, so you'll want to use deldir to turn the results into a surface. For example,

library(mgcv)

x<- rnorm(200)
y<- rnorm(200)
z<-rnorm(200)

tab<-data.frame(x,y,z)
tab

#surface wireframe:

mod <- gam(z ~ te(x, y), data = tab)

library(rgl)
library(deldir)

zfit <- fitted(mod)
col <- cm.colors(20)[1 + 
         round(19*(zfit - min(zfit))/diff(range(zfit)))]

persp3d(deldir(x, y, z = zfit), col = col)
aspect3d(1, 2, 1)

This gives a nice smooth surface, for example

Answer 2

A simpler way, without the delaunay stuff:

library(mgcv)

x <- rnorm(200)
y <- rnorm(200)
z <- rnorm(200)

tab <- data.frame(x,y,z)

mod <- mgcv::gam(z ~ te(x, y), data = tab)
grid <- -5:5
zfit <- predict(mod, expand.grid(x = grid, y = grid))
persp3d(grid, grid, zfit)