In R (rgl), how to print shadows of points in plot3d? - r

In R, using package rgl, I'd like to add the shadows of the points in plot3d(), just like in the image below.
I've added the bottom grid using grid3d(), but still have no clue on how to add the shadows. If I plot the same points changing the 3rd axis value to its minimum value (-100 in the image), the plot area automatically increases, leaving a gap between the points and the grid. Is there a better way to do that?
I think it was obvious from the question, but here is a sample code:
library(rgl)
df <- data.frame(x=rnorm(100),
y=rnorm(100),
z=rnorm(100))
plot3d(df)
grid3d('z')

The idea of setting z to the minimal value fails because rgl makes the bounding region slightly bigger. But you can grab the z value from the grid, and use that. You can also tell rgl not to expand the bounding box to include the new points. This code does both things:
library(rgl)
df <- data.frame(x=rnorm(100),
y=rnorm(100),
z=rnorm(100))
plot3d(df)
id <- grid3d('z') # Get id values for grid
gridz <- rgl.attrib(id[1], "vertices")[1,3] # Use the first z value
save <- par3d(ignoreExtent = TRUE) # Ignore points for bbox
with(df, points3d(x, y, gridz, col = "gray"))# Plot the "shadows"
par3d(save) # Restore bbox status
Here's what I get:

there is now the convenience show2d function available to produce the desired 2D projections
library(rgl)
df <- data.frame(x=rnorm(100),
y=rnorm(100),
z=rnorm(100))
plot3d(df)
grid3d('z')
show2d({
par(mar=c(0,0,0,0))
plot(x = df$x, y = df$y,
col = "black")
})

Related

Can I re-scale the x/y axis aspect ratio in R with rayshader?

I have some data from lab equipment that can be represented as a matrix by a contour plot/heatmap.
I would like to try illustrating this data in R with the rayshader package.
My problem is that the data is far from square in shape, the matrix is 33 rows by 48003 columns. When I plot this with rayshader I get a thin line:
library(dplyr)
library(rayshader)
set.seed(1742)
df <- matrix(rnorm(10000), nrow = 10)
rownames(df) <- 1:10
colnames(df) <- seq(0.01, 10, 0.01)
df %>%
sphere_shade(texture = "desert") %>%
plot_map()
Is there a way to make rayshader plot this as a square by manipulating the x/y aspect ratios? Or to plot them on an equivalent scale (one dimension collects data much faster than the other)? I can't find anything in the docs.
In this example, I tried naming the rows and columns so they were both collected over 10 minutes, but it didn't change the result.
The end result should look similar to:
library(plotly)
set.seed(1742)
plot_ly(z = ~matrix(rnorm(10000), nrow = 10)) %>%
add_surface()
Many thanks.
Solution for rayshader::plot_3d() is to use scale = c(x, y, z), which will alter the x/y/z aspect ratios. This was hidden, but didn't take that much sluthing to find the answer. It is a setting in rgl::par3d(), which is called by plot_3d().
However, I couldn't get plot_map() to work. When I tried adding the argument asp = 1, which is used by rgl::par3d(), it threw errors.

Dotchart with secondary axis

I'm trying to produce a dotchart with a secondary axis on top. However once I plot the second dotchart (with a par(new=T)), I can't figure out how not to display the axis ticks over the previous ones in axis side=1. Here's my code with mock data:
y1_i <- c(2,8,2,14,2)
y2_i <- c(15,17,28,22,30)
y1_f <- c(4,9,11,16,7)
y2_f <- c(13,11,16,11,21)
y=c(y1_i,y2_i,y1_f,y2_f)
x <- c("AAEG","AALO","AGAM","ACHR","AALB")
y1=c(y1_i,y1_f)
y2=c(y2_i,y2_f)
dotchart(y1_i,labels=x,xlab="N50 length",xlim = c(0,max(y1)))
par(new=T)
dotchart(y2_i,labels=x,xlim = c(0,max(y2)))
axis(side=3)
Also, if possible, I would like to add a second data set which would be slightly pushed vertically above the first dataset (to not overlap it), but still corresponding to the same y-axis categories.
Thank you for any suggestion :)
Found it, by using dotchart2 from the Hmisc package
library(Hmisc)
y1_i <- c(2,8,2,14,2)
y2_i <- c(15,17,28,22,30)
y1_f <- c(4,9,11,16,7)
y2_f <- c(13,11,16,11,21)
y=c(y1_i,y2_i,y1_f,y2_f)
x <- c("AAEG","AALO","AGAM","ACHR","AALB")
y1=c(y1_i,y1_f)
y2=c(y2_i,y2_f)
y1_i <- c(2,8,2,14,2)
y2_i <- c(15,17,28,22,30)
y1_f <- c(4,9,11,16,7)
y2_f <- c(13,11,16,11,21)
y=c(y1_i,y2_i,y1_f,y2_f)
x <- c("AAEG","AALO","AGAM","ACHR","AALB")
y1=c(y1_i,y1_f)
y2=c(y2_i,y2_f)
dotchart2(y1_i,labels=x,xlab="N50 length",xlim = c(0,max(y1)))
par(new=T)
dotchart2(y2_i,labels=x,xlim = c(0,max(y2)),xlab="Scaffold number",lines=F,xaxis=F)
axis(side=3,xlab="Scaffold number")

adding data on top of a 3D base map using R

I am trying to plot a 3D space time cube in R and I want to have a basemap.
I am using rgl library. I know how to plot my data using x, y and z, where z is the time variable. I have also managed to download a map that I want to use as reference from openstreetmap, using the library in R. However, I cannot find a way to plot my data on the map in a 3D environment. I found the following code in several sites and as an answer to a similar question:
map3d <- function(map, ...){
if(length(map$tiles)!=1){stop("multiple tiles not implemented") }
nx = map$tiles[[1]]$xres
ny = map$tiles[[1]]$yres
xmin = map$tiles[[1]]$bbox$p1[1]
xmax = map$tiles[[1]]$bbox$p2[1]
ymin = map$tiles[[1]]$bbox$p1[2]
ymax = map$tiles[[1]]$bbox$p2[2]
xc = seq(xmin,xmax,len=ny)
yc = seq(ymin,ymax,len=nx)
colours = matrix(map$tiles[[1]]$colorData,ny,nx)
m = matrix(0,ny,nx)
surface3d(xc,yc,m,col=colours, ...)
}
However, I cannot really understand how it works.
Here's my code so far:
library(rgl)
library(ggplot2)
library(OpenStreetMap)
map <- openmap(c(53.5,73.6),c(15.7,134.7),type= 'esri-topo')
plot3d(x,y,z, col= colour) # to plot my data
autoplot(map) # to plot the map. though this is 2D
Again, I know how to plot my data on a 2D map. Confused with the 3D.
Any hints and tips on how to do this?
One option is to use the newish 'show2d' function in 'rgl'.
library(rgl)
library(OpenStreetMap)
library(raster)
map <- openmap(c(53.5,73.6),c(15.7,134.7),type= 'esri-topo')
## fake up some xyz
xyz <- expand.grid(x = map$bbox$p1,
y = map$bbox$p2,
z = 1:4)
plot3d(xyz, col = "black") # to plot my data
EDIT: this is wrong, it's only fitted to the bounding box
getting the orientation right is confusing, needs to be check with x, y, z arguments to show2d.
show2d(raster::plotRGB(raster(map)))
This function captures the normal plot expression, writes it to PNG and then texture maps it onto a quad in the scene.
I can't quite see how to control the position of the quad for the image texture with the x, y, z args - work in progress.

Stacking of several Surface plots in 3D-View

Lets consider that I have five 2D-Matrices which describe the magnetic field at different z-Layers. A nice, smoothed version of a 2D-Surface plot can be obtained as follows:
data2_I<-matrix(c(1.0,1.0,0.6,0.6,0.7,0.9,0.9,0.5,0.5,0.5,0.7,0.9,0.9,0.6,0.3,0.4,0.7,0.9,0.9,0.7,0.5,0.5,0.6,0.9,0.9,0.7,0.6,0.6,1.0,1.0), nrow=5)
Z = as.vector(data2_I)
length(Z)
XY=data.frame(x=as.numeric(gl(5,1,30)),y=as.numeric(gl(5,6,30)))
t=Tps(XY,Z)
surface(t)
Now it would be great if I could get a 3D-plot where at different z-Positions these surfaces are plotted. Is there a possibility to do that?
I found an alternative approach: With the package rgl I and the function surface 3D I can stack several 3D-Surface plots within one open3d-window. Lets look at a small example:
library("rgl")
data2_I<-matrix(c(1.0,1.0,0.6,0.6,0.7,0.9,0.9,0.5,0.5,0.5,0.7,0.9,0.9,0.6,0.3,0.4,0.7,0.9,0.9,0.7,0.5,0.5,0.6,0.9,0.9,0.7,0.6,0.6,1.0,1.0), nrow=5)
data0_I<-matrix(c(1.0,1.0,0.6,0.6,0.7,0.9,0.9,0.5,0.5,0.5,0.7,0.9,0.9,0.6,0.3,0.4,0.7,0.9,0.9,0.7,0.5,0.5,0.6,0.9,0.9,0.7,0.6,0.6,1.0,1.0), nrow=5)
data1_I<-2*data0_I
data2_I<-1/data1_I
elv=0
offs=5*elv+1
z0 <- scale*data0_I
z1 <- scale*data1_I
z2 <- scale*data2_I
x <- 1:nrow(z0)
y <- 1:ncol(z0)
palette <- colorRampPalette(c("blue","green","yellow", "red"))
col.table <- palette(256)
open3d(windowRect=c(50,50,800,800))
surface3d(x, y, elv*z0, color = col.table[cut(z0, 256)], back = "lines")
surface3d(x, y, elv*z1+1*offs, color = col.table[cut(z1, 256)], back = "lines")
surface3d(x, y, elv*z2+2*offs, color = col.table[cut(z2, 256)], back = "lines")
axes3d()
aspect3d(1,1,2)
The variables offsand elv are included for cosmetic purposes: offs controls the space between two surface plots and elevation how the z-axes of the surface3d-plots should scale. As I wanted to have a 2D surface plot without any elevation I set it to zero.

How can I overlay two dense scatter plots so that I can see the outlines of each in R or Matlab?

See this example
This was created in matlab by making two scatter plots independently, creating images of each, then using the imagesc to draw them into the same figure and then finally setting the alpha of the top image to 0.5.
I would like to do this in R or matlab without using images, since creating an image does not preserve the axis scale information, nor can I overlay a grid (e.g. using 'grid on' in matlab). Ideally I wold like to do this properly in matlab, but would also be happy with a solution in R. It seems like it should be possible but I can't for the life of me figure it out.
So generally, I would like to be able to set the alpha of an entire plotted object (i.e. of a matlab plot handle in matlab parlance...)
Thanks,
Ben.
EDIT: The data in the above example is actually 2D. The plotted points are from a computer simulation. Each point represents 'amplitude' (y-axis) (an emergent property specific to the simulation I'm running), plotted against 'performance' (x-axis).
EDIT 2: There are 1796400 points in each data set.
Using ggplot2 you can add together two geom_point's and make them transparent using the alpha parameter. ggplot2 als adds up transparency, and I think this is what you want. This should work, although I haven't run this.
dat = data.frame(x = runif(1000), y = runif(1000), cat = rep(c("A","B"), each = 500))
ggplot(aes(x = x, y = y, color = cat), data = dat) + geom_point(alpha = 0.3)
ggplot2 is awesome!
This is an example of calculating and drawing a convex hull:
library(automap)
library(ggplot2)
library(plyr)
loadMeuse()
theme_set(theme_bw())
meuse = as.data.frame(meuse)
chull_per_soil = ddply(meuse, .(soil),
function(sub) sub[chull(sub$x, sub$y),c("x","y")])
ggplot(aes(x = x, y = y), data = meuse) +
geom_point(aes(size = log(zinc), color = ffreq)) +
geom_polygon(aes(color = soil), data = chull_per_soil, fill = NA) +
coord_equal()
which leads to the following illustration:
You could first export the two data sets as bitmap images, re-import them, add transparency:
library(grid)
N <- 1e7 # Warning: slow
d <- data.frame(x1=rnorm(N),
x2=rnorm(N, 0.8, 0.9),
y=rnorm(N, 0.8, 0.2),
z=rnorm(N, 0.2, 0.4))
v <- with(d, dataViewport(c(x1,x2),c(y, z)))
png("layer1.png", bg="transparent")
with(d, grid.points(x1,y, vp=v,default="native",pch=".",gp=gpar(col="blue")))
dev.off()
png("layer2.png", bg="transparent")
with(d, grid.points(x2,z, vp=v,default="native",pch=".",gp=gpar(col="red")))
dev.off()
library(png)
i1 <- readPNG("layer1.png", native=FALSE)
i2 <- readPNG("layer2.png", native=FALSE)
ghostize <- function(r, alpha=0.5)
matrix(adjustcolor(rgb(r[,,1],r[,,2],r[,,3],r[,,4]), alpha.f=alpha), nrow=dim(r)[1])
grid.newpage()
grid.rect(gp=gpar(fill="white"))
grid.raster(ghostize(i1))
grid.raster(ghostize(i2))
you can add these as layers in, say, ggplot2.
Use the transparency capability of color descriptions. You can define a color as a sequence of four 2-byte words: muddy <- "#888888FF" . The first three pairs set the RGB colors (00 to FF); the final pair sets the transparency level.
AFAIK, your best option with Matlab is to just make your own plot function. The scatter plot points unfortunately do not yet have a transparency attribute so you cannot affect it. However, if you create, say, most crudely, a bunch of loops which draw many tiny circles, you can then easily give them an alpha value and obtain a transparent set of data points.

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