3d plot in R - Patch

Question

I have the following data in a data frame: ``` **x** in (0,1) **y** in [0,1] **z** in [0,1] ``` For example: ``` X,Y,Z 0.1, 0.2, 0.56 0.1, 0.3, 0.57 ... ``` I'd like to plot them on this type of chart: I tried on R, but all I could get was a not-so-fancy 3d scatterplot. I also read about the lattice 3d wireframe, but I couldn't get my head around it. What am I supposed to do to get a Matlab like wireframe in R? What data transforms are involved? This is the sample code from the documentation: ``` x <- seq(-pi, pi, len = 20) y <- seq(-pi, pi, len = 20) g <- expand.grid(x = x, y = y) g$z <- sin(sqrt(g$x^2 + g$y^2)) wireframe(z ~ x * y, g, drape = TRUE, aspect = c(3,1), colorkey = TRUE) ``` I don't find it particularly clear. EDIT: the `persp3d` function works fine, and I was able to generate a 3d plot with one colour. How can I set a colour scale relative to the z value? Thanks for any hints, Mulone

Accepted Answer

Use `outer` to create the z values and then use `persp` to plot:

```
z <- outer(x,y, function(x,y) sin(sqrt(x^2+y^2)))
persp(x,y,z)
```

There are options for colouring and setting the viewing angle, see `?persp`. See the fourth example for Matlab style colouring.

For an interactive plot, consider using `persp3d` in the `rgl` package:

```
require(rgl)
persp3d(x,y,z,col="blue")
```

Edit

To add colour, there is a slight difference from the method in `persp`, since the colour relates to the vertex rather than the centre of the facet, but it makes it easier.

```
jet.colors <- colorRampPalette( c("blue", "green") ) 
pal <- jet.colors(100)
col.ind <- cut(z,100) # colour indices of each point
persp3d(x,y,z,col=pal[col.ind])
```

The help file recommends adding the parameter `smooth=FALSE`, but that's down to personal preference.

3d plot in R - Patch

Solution

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