point to line interpolation using heading in R - r

I can draw a spline through 10 successive points, like done in this post
set.seed(1)
n <- 10
x <- runif(n)
y <- runif(n)
p <- cbind(x,y)
xlim <- c(min(x) - 0.1*diff(range(x)), c(max(x) + 0.1*diff(range(x))))
ylim <- c(min(y) - 0.1*diff(range(y)), c(max(y) + 0.1*diff(range(y))))
plot(p, xlim=xlim, ylim=ylim)
text(p, labels=seq(n), pos=3)
xspline(x, y, shape = c(0,rep(-1, 10-2),0), border="red")
But is it possible to force the direction of the line in each point to be at a specific heading? - For examle if the heading was 0 in point #2, it would be forces to go straight up, and not as now in a north-easterly direction.
Like on a compass: 0=north, 90=east, 180=south and 270=west.
For example you could use the following 10 headings:
h <- round(runif(n, min = 0, max = 359),0)
Also, the output should be able to be saved as a spatial line.

Related

How to add miniature to plot and repeat this for multiple plots side by side?

There's a nice answer around to plot a miniature plot within a plot. I wrapped it in a function which works fine for a single plot.
myPlot <- function(x, y) {
# main plot
plot(x)
# calculate position of inset
pp <- par("plt")
x0 <- pp[2] - (pp[2] - pp[1]) * 0.225
x1 <- pp[2] - .01
y0 <- pp[4] - (pp[4] - pp[3]) * 0.225
y1 <- pp[4] - .01
# set position for inset
op <- par(fig=c(x0, x1, y0, y1), mar=c(0, 0, 0, 0), new=TRUE)
# add inset grey background
plot.new()
u <- par("usr")
rect(u[1], u[2], u[4], u[3], col="grey80")
# add inset
par(new=TRUE)
plot(y, col=2)
par(op)
}
myPlot(x, y)
However, when I useMap to loop over several data lists, in order to make multiple plots of this type side by side, there seems to be a mess with the pars. The miniature appears as a new plot and not within the main plot. Also a new device is opened after one iteration (i.e. old plot gets overwritten).
op1 <- par(mfrow=c(1, 2))
Map(function(x, y) myPlot(x, y), list(d0, d0), list(d0_inset, d0_inset))
par(op1)
When I use Map(function(x, y) myPlot(x, y), list(d0, d0), list(d0_inset, d0_inset)) alone, though, there are two perfect plots in the plot queue (of RStudio). Thus the plot.new() and par(new=TRUE) might not be the issue here.
What I actually want is this:
myPlot() should throw a number of main plots with miniatures inside corresponding to the length of the data lists when using Map and fit it into the par(mfrow=...).
Does anyone have a clue how to solve this using base R functionalities?
Data:
x <- data.frame(x = rnorm(150, sd=5), y = rnorm(150, sd=5))
y <- data.frame(x = rnorm(1500, sd=5), y = rnorm(1500, sd=5))
There's a couple of points here Jay. The first is that if you want to continue to use mfrow then it's best to stay away from using par(fig = x) to control your plot locations, since fig changes depending on mfrow and also forces a new plot (though you can override that, as per your question). You can use plt instead, which makes all co-ordinates relative to the space within the fig co-ordinates.
The second point is that you can plot the rectangle without calling plot.new()
The third, and maybe most important, is that you only need to write to par twice: once to change plt to the new plotting co-ordinates (including a new = TRUE to plot it in the same window) and once to reset plt (since new will reset itself). This means the function is well behaved and leaves the par as they were.
Note I have added a parameter, at, that allows you to specify the position and size of the little plot within the larger plot. It uses normalized co-ordinates, so for example c(0, 0.5, 0, 0.5) would be the bottom left quarter of the plotting area. I have set it to default at somewhere near your version's location.
myPlot <- function(x, y, at = c(0.7, 0.95, 0.7, 0.95))
{
# Helper function to simplify co-ordinate conversions
space_convert <- function(vec1, vec2)
{
vec1[1:2] <- vec1[1:2] * diff(vec2)[1] + vec2[1]
vec1[3:4] <- vec1[3:4] * diff(vec2)[3] + vec2[3]
vec1
}
# Main plot
plot(x)
# Gray rectangle
u <- space_convert(at, par("usr"))
rect(u[1], u[3], u[2], u[4], col="grey80")
# Only write to par once for drawing insert plot: change back afterwards
plt <- par("plt")
plt_space <- space_convert(at, plt)
par(plt = plt_space, new = TRUE)
plot(y, col = 2)
par(plt = plt)
}
So we can test it with:
x <- data.frame(x = rnorm(150, sd = 5), y = rnorm(150, sd = 5))
y <- data.frame(x = rnorm(1500, sd = 5), y = rnorm(1500, sd = 5))
myPlot(x, y)
par(mfrow = c(1, 2))
myPlot(x, y)
myPlot(x, y)
par(mfrow = c(2, 2))
for(i in 1:4) myPlot(x, y)

Is it possible to plot a plane by it's equation f(x) + g(y) + h(z) + c = 0?

Is it possible to plot a plane, given the equation
x^2 + y^2 - 1.6z^2 + 1 = 0
with R?
It should look like this:
(Image source: https://commons.wikimedia.org/wiki/File:Zweischaliges_Hyperboloid.png)
What I've tried
library(rgl)
x = -20:20
xs = rep(x, 40)
y = -20:20
ys = rep(y, each=40)
z = (-(-1-x^2-y^2)/1.6)^0.5
plot3d(x=xs, y=ys, z=z)
This does plot the upper part, but I would like to see the lower part, too. Also, the plot doesn't look nice.
Answering the question I posed in my comment and providing what I think is a complete answer using rgl
library(rgl)
# define +ve function and plot it
zfun <- function(x,y) (-(-1-x^2-y^2)/1.6)^0.5
persp3d(zfun, c(-20,20), c(-20,20), n = 101)
# define x-y grid for second surface
xyvec <- seq(-20, 20, length.out = 101)
# calculate surface as -ve function and plot it
zmat <- -outer(xyvec, xyvec, zfun)
surface3d(xyvec, xyvec, zmat)

Time lapse plotting

I am new to R environment. I have generated a simulated time lapse plot using the following code.
seq_x<-seq(1,10)
seq_y<-function(y)
{
z<-y^2+y+1
return (c(z))
}
yrange<-seq_y(1)
yrange[2]<-seq_y(length(seq_x))
for(i in 1:length(seq_x) )
{
xdata<-seq_x[1:i]
ydata<-seq_y(xdata)
plot(xdata,ydata,xlim=range(seq_x),ylim=range(yrange),type="o",col="royalblue",plot.first=grid())
Sys.sleep(1)
}
I get the following plot(after the final iteration).
Now I need to plot a straight line and a circle right across the plot as shown below.
The straight line should grow with the data sequence. The circle should be at the center of the data sequence with user specified radius. Any advice in this regard will be highly appreciated.
Try this:
#draw circle
require(plotrix)
userRadius <- 1
draw.circle(median(xdata), median(ydata), userRadius)
#draw line
segments(x0=xdata[1],y0=ydata[1],
x1=xdata[length(xdata)],y1=ydata[length(ydata)])
You can use lines to add additional lines to your plot. Then you just have to calculate the points on the circle (or ellipsis) and you can draw both the extra line and the circle.
# data
x <- seq(1,10)
y <- x^2 + x + 1
# function to calculate points on the ellipsis
ellipsis_fct <- function(mx, my, rx, ry){
phi <- seq(0, 2*pi, length = 100) # change length if you need better resolution
data.frame(x = mx + rx*sin(phi),
y = my + ry*cos(phi))
}
# actually calculate the points.
circ <- ellipsis_fct(mean(range(x)), mean(range(y)), diff(range(x))/5, diff(range(y))/5)
# plotting commands
plot(x, y, xlim=range(x), ylim=range(y), type="o", col="royalblue", plot.first=grid())
lines(range(x), range(y), col = "darkred", lty = "dashed")
lines(circ, col = "orange")

How to make 3D line plot in R (waterfall plot)

I would like to create a waterfall plot in R (XYYY) from my data.
So far, I use this code:
load("myData.RData")
ls()
dim(data)
##matrix to xyz coords
library(reshape2)
newData <- melt(data, id="Group.1")
dim(newData)
head(newData)
tail(newData)
newDataO <- newData[c(2,1,3)]
head(newDataO)
##color scale for z axis
myColorRamp <- function(colors, values) {
v <- (values - min(values))/diff(range(values))
x <- colorRamp(colors)(v)
rgb(x[,1], x[,2], x[,3], maxColorValue = 255)
}
cols <- myColorRamp(c("darkblue","yellow","darkorange","red","darkred"),newDataO$value)
##3D scatter
library(rgl)
plot3d(newDataO$variable, newDataO$Group.1, newDataO$value, xlab="", ylab="", zlab="", type="p", col=cols, box=FALSE, axes=FALSE)
rgl.postscript("persptrial_060514.eps","eps")
to get this plot:
https://dl.dropboxusercontent.com/u/14906265/persptrial_060514.jpg
I have also use this option in 2d with polygon but the result does not properly show the differential effect between both plots (left vs right).
I do not know whether something like persp3d could do the job but I am not familiar enough with writing code to achieve it. Any help will be very much appreciated.
It seems to me that the simplest way of doing a waterfall plot in R is to add all the lines manually in a loop.
library(rgl)
# Function to plot
f <- function(x, y) sin(10 * x * y) * cos(4 * y^3) + x
nx <- 30
ny <- 100
x <- seq(0, 1, length = nx)
y <- seq(0, 1, length = ny)
z <- outer(x, y, FUN = f)
# Plot function and add lines manually
surface3d(x, y, z, alpha = 0.4)
axes3d()
for (i in 1:nx) lines3d(x[i], y, z[i, ], col = 'white', lwd = 2)

plot level lines (2 circumferences) on a 3d plot

I'm trying to plot the two circumferences with dimensions xy together with the 3d plot and colour the intersection of the two circles, how can I do that?
# objective function
x <- seq(-1,1,.1)
y <- seq(-1,1,.1)
z <- x^2 + y^2
library(scatterplot3d)
library(plotrix)
scatterplot3d(x,y,z,pch=19,color="royalblue4")
draw.circle (1,1,1)
draw.circle (1,-1,1)
I'm not really into mathematic stuff, but I'll post as answer because it might be of use and, also, is too big for a comment. Excuse any ignorance of mine, though, if I post nonsense.
#your data
library(scatterplot3d)
x <- seq(-1,1,.1)
y <- seq(-1,1,.1)
z <- x^2 + y^2
ang = 60 #angle of the 3D plot. experiment with different values
#your 3D plot, with extended xx', yy' limits
sp3d <- scatterplot3d(x, y, z, pch=19, color="royalblue4",
xlim = c(-1, 3), ylim = c(-3, 3), angle = ang)
#to use parametric equations of circles
f <- seq(-2*pi, 2*pi, 0.1)
#circle1
sp3d$points(x = 1 + 1*cos(f), y = 1 + 1*sin(f), z = rep(0, length(f)), type = "l")
#circle2
sp3d$points(x = 1 + 1*cos(f), y = -1 + 1*sin(f), z = rep(0, length(f)), type = "l")
The plot is:

Resources