3D surface plot in R - r

I'm trying to create a 3D plot in R-Project. I know there was a question like this before but I couldn't solve my problems with the answers there.
What I have is:
Vdot_L = c(0,1,2,3,4,5,6,7,8,9,10)
Qdot_verd = c(2000,2100,2200,2300,2400,2500,2600,2700,2800,2900,3000)
zeta_ex = 0.4
T_U = 293.15 #K
T_verd = 273.15 #K
T_cond=Vdot_L*2+T_U
epsilon_k = zeta_ex * T_verd/(T_cond - T_verd)
Pfun <- function(a,b) {a/b}
P <- outer(Qdot_verd, epsilon_k, FUN="Pfun")
What I'd like to create is a colored surface plot with Vdot_L on the x-Axis, Qdot_verd on the y-Axis and P on the z-Axis. I'm thanful for every help.

So something like this??
library(rgl)
zlim <- range(P,na.rm=T)
zlen <- zlim[2] - zlim[1] + 1
color.range <- rev(rainbow(zlen)) # height color lookup table
colors <- color.range[P-zlim[1]+1] # assign colors to heights for each point
persp3d(Vdot_L, Qdot_verd, P, col=colors)

Have you investigated the Plot3D package?
http://cran.r-project.org/web/packages/plot3D/plot3D.pdf
There's a method in here called surf3d which seems like it would do what you want. After importing the package, cast your values to matrix and write:
surf3d(Vdot_L, Qdot_verd, P)
There's also a color parameter which you can adjust.
Alternatively, use rgl, and avoid the matrix issue:
rgl.surface(Vdot_L, Qdot_verd, P)
Also check out these posts for more info:
R: 3D surface plot from 2D matrix
How to create 3D - MATLAB style - surface plots in R

Related

replicating an rgl viewpoint in lattice

It would be convenient to interactively select a decent viewpoint using rgl and then adopt the same orientation in a lattice 3d-plot. For example, given the following plot using a non-informative viewpoint.
library(lattice)
wireframe(volcano, screen = list(x=0, y=0, z=0))
The same can be opened in rgl by
library(rgl)
persp3d(volcano)
view3d(0, 0)
Interactively it is easy to rotate the plot to an informative view.
The matrix giving the current rgl viewpoint in can be extracted by
p <- par3d()
p$userMatrix
How can this matrix be converted into corresponding x,y,z screen parameters to replicate the view in lattice?
UPDATE 1
I tried out 42's conversion below. The code shows the rgl plot and the corresponding lattice plot per row. If I implemented it correctly (see code below), there appears to still be an issue.
# convert rgl viewpoint into lattice
# screen orientation
rgl_to_lattice_viewpoint <- function()
{
p <- par3d()
rotm <- p$userMatrix
B = 360*atan(rotm[1,2]/rotm[2,2])/(2*pi)
P = 360*asin(-rotm[3,2])/(2*pi)
H = 360*atan(rotm[3,1]/rotm[3,3])/(2*pi)
list(x=-B, y=-P, z=-H)
}
# read and plot PNG image
plot_png <- function(f)
{
img <- readPNG(f)
rimg <- as.raster(img) # raster multilayer object
plot(NULL, xlim=c(0,1), ylim=c(0,1), xlab = "", ylab = "",
asp=1, frame=F, xaxt="n", yaxt="n")
rasterImage(rimg, 0, 0, 1, 1)
}
# create rgl snapshot with random rotation and
# corresponding lattice wireframe plot
lattice_plus_rgl_plot <- function()
{
# rgl plot random rotation
persp3d(volcano, col = "green3")
theta <- sample(-180:180, 1)
phi <- sample(-90:90, 1)
view3d(theta, phi, fov=40)
v <- rgl_to_lattice_viewpoint()
f <- tempfile(fileext = ".png")
rgl.snapshot(f)
rgl.close()
# lattice plot
f2 <- tempfile(fileext = ".png")
png(f2)
print(wireframe(volcano, screen = v))
dev.off()
# plot both
plot_png(f)
plot_png(f2)
}
# CREATE SOME PLOTS
library(rgl)
library(lattice)
library(png)
par(mfrow=c(3,2), mar=c(0,0,0,0))
replicate(3, lattice_plus_rgl_plot())
I used the answer to this question for conversion from a rotation matrix to angles: Conversion euler to matrix and matrix to euler . I admit to concern that I see another somewhat different answer here: How to calculate the angle from Roational matrix . (My linear algebra is not good enough to determine which of these is correct.)
p <- par3d()
rotm <- p$userMatrix
B = 360*atan(rotm[1,2]/rotm[2,2])/(2*pi)
P = 360*asin(-rotm[3,2])/(2*pi)
H = 360*atan(rotm[3,1]/rotm[3,3])/(2*pi)
> print(list(B,P,H))
[[1]]
[1] 41.54071
[[2]]
[1] 40.28412
[[3]]
[1] 41.24902
At that point I had already rotated the RGL-object to roughly the "viewing point" that you had suggested. I discovered by experimentation that the negative values supplied to the wireframe call delivered apparently correct results. "Viewer rotation angles" are plausibly seen as the negative for "object rotation angles".
png(); print(wireframe(volcano, screen = list(x=-B, y=-P, z=-H)) ); dev.off()
There is a rotate.wireframe function in the TeachingDemos package but it does not play well with concurrently running rgl plots. (No plot was apparent until I closed the rgl device.) It also seemed kind of buggy when running on a Mac (thick black line across the lattice plot). It uses the X11/XQuartz facilities to manage interaction via tk/tcl functions and I was unable to reproduce the plots from the angles being displayed. Looking at the code I'm not able to understand why that should be so. But your mileage may vary.
This version of your function uses conversions from the orientlib package, and makes the rotation matrix an argument:
rgl_to_lattice_viewpoint <- function(rotm = par3d("userMatrix"))
{
e <- -orientlib::eulerzyx(orientlib::rotmatrix(rotm[1:3, 1:3]))#x*180/pi
list(z = e[1], y = e[2], x = e[3])
}
Note that the z, y, x order is essential.
Using it in place of your function, I get this output:
These get the rotation right. I don't know if it's also possible to get the perspective to match.
Edited to add: rgl version 0.95.1468, so far available only on R-forge,
contains a version of this function and one for base graphics as well.

R contour levels don't match filled.contour

Hopefully a straightforward question but I made a simple figure in R using filled.contour(). It looks fine, and what it should like given the data. However, I want to add a reference line along a contour for 0 (level = 0), and the plotted line doesn't match the colors on the filled.contour figure. The line is close, but not matching with the figure (and eventually crossing over another contour from the filled.contour plot). Any ideas why this is happening?
aa <- c(0.05843150, 0.11300040, 0.15280030, 0.183524400, 0.20772430, 0.228121000)
bb <- c(0.01561055, 0.06520635, 0.10196237, 0.130127650, 0.15314544, 0.172292410)
cc <- c(-0.02166599, 0.02306650, 0.05619421, 0.082193680, 0.10334837, 0.121156780)
dd <- c(-0.05356592, -0.01432910, 0.01546647, 0.039156660, 0.05858709, 0.074953650)
ee <- c(-0.08071987, -0.04654243, -0.02011676, 0.000977798, 0.01855881, 0.033651089)
ff <- c(-0.10343798, -0.07416114, -0.05111547, -0.032481132, -0.01683215, -0.003636035)
gg <- c(-0.12237798, -0.09753544, -0.07785126, -0.061607548, -0.04788856, -0.036169540)
hh <-rbind(aa,bb,cc,dd,ee,ff,gg)
z <- as.matrix(hh)
y <- seq(0.5,1.75,0.25)
x <- seq(1,2.5,0.25)
filled.contour(x,y,z,
key.title = title(main=expression("log"(lambda))),
color.palette = topo.colors) #This works
contour(x,y,z, level=0,add=T,lwd=3) #This line doesn't match plot
This is completely answered in the ?filled.contour help page. In the Notes section it states
The output produced by filled.contour is actually a combination of two plots; one is the filled contour and one is the legend. Two separate coordinate systems are set up for these two plots, but they are only used internally – once the function has returned these coordinate systems are lost. If you want to annotate the main contour plot, for example to add points, you can specify graphics commands in the plot.axes argument. See the examples.
And the examples given in that help page show how to annotate on top of the main plot. In this particular case, the correct way would be
filled.contour(x,y,z,
key.title = title(main=expression("log"(lambda))),
color.palette = topo.colors,
plot.axes = {
axis(1)
axis(2)
contour(x,y,z, level=0,add=T,lwd=3)
}
)
which produces

Concentric Circles like a grid, centered at origin

I would like to include a sequence of concentric circles as a grid in a plot of points. The goal is to give the viewer an idea of which points in the plot have approximately the same magnitude.
I created a hack to do this:
add_circle_grid <- function(g,ncirc = 10){
gb <- ggplot_build(g)
xl <- gb$panel$ranges[[1]]$x.range
yl <- gb$panel$ranges[[1]]$y.range
rmax = sqrt(max(xl)^2+max(yl)^2)
theta=seq(from=0,by=.01,to=2*pi)
for(n in 1:ncirc){
r <- n*rmax/ncirc
circle <- data.frame(x=r*sin(theta),y=r*cos(theta))
g<- g+geom_path(data=circle,aes(x=x,y=y),alpha=.2)
}
return(g+xlim(xl)+ylim(yl))
}
xy<-data.frame(x=rnorm(100),y=rnorm(100))
ggplot(xy,aes(x,y))+geom_point()
ggg<-add_circle_grid(ggplot(xy,aes(x,y))+geom_point())
print(ggg)
But I was wondering if there is a more ggplot way to do this. I also considered using polar coordinates but it does not allow me to set x- and y-limits in the same way.
Finally, I wouldn't mind little text labels indicating the radius of each circle.
EDIT
Perhaps this is asking too much but there are two other things that I would like.
The axis limits should stay the same (which can be done via ggplot_build)
Can this work with facets? As far as I can tell you would need to somehow figure out the facets if I want to add the circles dynamically.
set.seed(1)
xy <- data.frame(x=rnorm(100),y=rnorm(100))
rmax = sqrt(max(xy$x)^2+max(xy$y)^2)
theta=seq(from=0,by=.01,to=2*pi)
ncirc=10
dat.circ = do.call(rbind,
lapply(seq_len(ncirc),function(n){
r <- n*rmax/ncirc
data.frame(x=r*sin(theta),y=r*cos(theta),r=round(r,2))
}))
rr <- unique(dat.circ$r)
dat.text=data.frame(x=rr*cos(30),y=rr*sin(30),label=rr)
library(ggplot2)
ggplot(xy,aes(x,y))+
geom_point() +
geom_path(data=dat.circ,alpha=.2,aes(group=factor(r))) +
geom_text(data=dat.text,aes(label=rr),vjust=-1)
How about this with ggplot2 and grid:
require(ggplot2)
require(grid)
x<-(runif(100)-0.5)*4
y<-(runif(100)-0.5)*4
circ_rads<-seq(0.25,2,0.25)
qplot(x,y)+
lapply(circ_rads,FUN=function(x)annotation_custom(circleGrob(gp=gpar(fill="transparent",color="black")),-x,x,-x,x))+
geom_text(aes(x=0,y=circ_rads+0.1,label=circ_rads)) + coord_fixed(ratio = 1)

How to create 3D - MATLAB style - surface plots in R

I find it challenging to create aesthetically pleasing 3D surfaces in R. I am familiar with the solutions (persp, image, wireframe, lattice, rgl and several other solutions in other questions in SO), but the results are not nice.
Is it possible to create 3D surface plots in R like in MATLAB?
Here is the MATLAB code
% Create a grid of x and y points
points = linspace(-2, 0, 20);
[X, Y] = meshgrid(points, -points);
% Define the function Z = f(X,Y)
Z = 2./exp((X-.5).^2+Y.^2)-2./exp((X+.5).^2+Y.^2);
% "phong" lighting is good for curved, interpolated surfaces. "gouraud"
% is also good for curved surfaces
surf(X, Y, Z); view(30, 30);
shading interp;
light;
lighting phong;
title('lighting phong', 'FontName', 'Courier', 'FontSize', 14);
The plot is modern, colorful, aesthetically pleasing, the code syntax is very readable.
Is this possible in base R?
jet.colors is the R-answer to one of hte Matlab color palettes:
points = seq(-2, 0, length=20)
#create a grid
XY = expand.grid(X=points,Y=-points)
# A z-function
Zf <- function(X,Y){
2./exp((X-.5)^2+Y^2)-2./exp((X+.5)^2+Y^2);
}
# populate a surface
Z <- Zf(XY$X, XY$Y)
zlim <- range(Z)
zlen <- zlim[2] - zlim[1] + 1
jet.colors <- # function from grDevices package
colorRampPalette(c("#00007F", "blue", "#007FFF", "cyan",
"#7FFF7F", "yellow", "#FF7F00", "red", "#7F0000"))
colorzjet <- jet.colors(100) # 100 separate color
require(rgl)
open3d()
rgl.surface(x=points, y=matrix(Z,20),
coords=c(1,3,2),z=-points,
color=colorzjet[ findInterval(Z, seq(min(Z), max(Z), length=100))] )
axes3d()
rgl.snapshot("copyMatlabstyle.png")
I will admit that getting the colors to line up with the "Z-axis" (which is actually the rgl y-axis) seemed very unintuitive. If you want the shiny, specular effect that Matlab delivers you can play with the angle of illumination.
You can also add or remove lighting:
clear3d(type = "lights")
light3d(theta=0, phi=0)
light3d(theta=0, phi=0) # twice as much light.
After:
grid3d("x")
grid3d("y")
grid3d("z")
rgl.snapshot("copyMatlabstyle3.png")
You could have put the y-grid "behind" the surface with:
grid3d("y+")
Similar tweaks to the axes3d or axis3d calls could move the location of the scales.
For further examples, look at http://rgm3.lab.nig.ac.jp/RGM/R_image_list and search for 'plot3d' which brings up examples of the R2BayesX::plot3d function, Look at Karline Soetaert's plot3D package vignette, "50 ways to plot a volcano"
This may well not do everything you want, but I'm posting it in hopes of attracting better answers.
X <- Y <- seq(-2, 0, length.out= 20)
Z <- outer(X,Y,
function(X,Y) 2/exp((X-.5)^2+Y^2)-2/exp((X+.5)^2+Y^2))
cc <- colorRamp(rev(rainbow(10)))
Zsc <- (Z-min(Z))/diff(range(Z))
rgbvec2col <- function(x) do.call(rgb,c(as.list(x),list(max=255)))
colvec <- apply(cc(Zsc),1,rgbvec2col)
library(rgl)
surface3d(X,Y,Z,col=colvec)
bbox3d(color=c("white","black"))

contour plot of a custom function in R

I'm working with some custom functions and I need to draw contours for them based on multiple values for the parameters.
Here is an example function:
I need to draw such a contour plot:
Any idea?
Thanks.
First you construct a function, fourvar that takes those four parameters as arguments. In this case you could have done it with 3 variables one of which was lambda_2 over lambda_1. Alpha1 is fixed at 2 so alpha_1/alpha_2 will vary over 0-10.
fourvar <- function(a1,a2,l1,l2){
a1* integrate( function(x) {(1-x)^(a1-1)*(1-x^(l2/l1) )^a2} , 0 , 1)$value }
The trick is to realize that the integrate function returns a list and you only want the 'value' part of that list so it can be Vectorize()-ed.
Second you construct a matrix using that function:
mat <- outer( seq(.01, 10, length=100),
seq(.01, 10, length=100),
Vectorize( function(x,y) fourvar(a1=2, x/2, l1=2, l2=y/2) ) )
Then the task of creating the plot with labels in those positions can only be done easily with lattice::contourplot. After doing a reasonable amount of searching it does appear that the solution to geom_contour labeling is still a work in progress in ggplot2. The only labeling strategy I found is in an external package. However, the 'directlabels' package's function directlabel does not seem to have sufficient control to spread the labels out correctly in this case. In other examples that I have seen, it does spread the labels around the plot area. I suppose I could look at the code, but since it depends on the 'proto'-package, it will probably be weirdly encapsulated so I haven't looked.
require(reshape2)
mmat <- melt(mat)
str(mmat) # to see the names in the melted matrix
g <- ggplot(mmat, aes(x=Var1, y=Var2, z=value) )
g <- g+stat_contour(aes(col = ..level..), breaks=seq(.1, .9, .1) )
g <- g + scale_colour_continuous(low = "#000000", high = "#000000") # make black
install.packages("directlabels", repos="http://r-forge.r-project.org", type="source")
require(directlabels)
direct.label(g)
Note that these are the index positions from the matrix rather than the ratios of parameters, but that should be pretty easy to fix.
This, on the other hand, is how easilyy one can construct it in lattice (and I think it looks "cleaner":
require(lattice)
contourplot(mat, at=seq(.1,.9,.1))
As I think the question is still relevant, there have been some developments in the contour plot labeling in the metR package. Adding to the previous example will give you nice contour labeling also with ggplot2
require(metR)
g + geom_text_contour(rotate = TRUE, nudge_x = 3, nudge_y = 5)

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