I have some scatter plots look like this:
scatter plot
The X values are discrete. For every X there's some Y values. I want to plot the density distribution of Y for each X. Like this:
density plot
Sorry that I don't know how to describe it, so I draw it by hand. Each red line is a density curve of Y corresponding to an X value. The blue line is the trend line.
In my limited experience with R and ggplot2, I don't have any ideas how to do it. I am searching for a long time on Google but no use. Please help or try to give some ideas how to achieve this. Thanks a lot!
Related
I am trying to simulate a minefield by plotting two Poisson distributed samples in the same plot, one with a higher intensity and smaller area than the other. This is the minefield and the other is just noise (stones, holes, metal) seen as points. I cannot get R to plot the points with the same units in the axis. Whatever I do, the points span the entire plot, even though I only want the X points to cover a quarter of the plot. My R-code is just the following:
library(spatstat)
Y = rpoispp(c(5),win=owin(c(0,10),c(0,10)))
X = rpoispp(c(10),win=owin(c(0,5),c(0,5)))
Please let me know if you can help me.
My guess is that you are doing something like:
> plot(Y)
> plot(X)
to plot the points.
The problem with this is that the default behavior of the plot function for the class ppp (which is what the rpoispp function returns) is to create a new plot with just its points. So the second plot call essentially erases the first plot, and plots its own points in a differently scaled window. You can override this behavior by setting the option add=TRUE for the second plot. So the code
> plot(Y)
> plot(X, add=TRUE, cols="red")
should get you something like:
Check out the docs (help(plot.ppp)) for more explanation and other options to prettify the plot.
I want to fit my vectors x ,y to some kind of curve, but they're both about 10k long with x-values very closely packed, so a scatter plot just ends up as a huge mess. What I'd like to do is to plot the AVERAGE of the y-values corresponding to one x-value.
For example:
y=rnorm(1000)
x=c(rep(1,500),rep(2,500))
plot(x,y)
I'd like this plot to only have two single points, one for x=1 and one for x=2. Any ideas?
plot(unique(x),tapply(y,x,mean))
or maybe even
plot(tapply(x,x,unique),tapply(y,x,mean))
I have a density function f, and I do MCMC sampling for it. To evaluate the goodness of the sampling, I need to plot the hist and curve within the same chart. The problem of
hist(samples);
curve(dfun,add=TRUE);
is that they are on the different scale: the frequency of a certain bin is usually hundreds, while the maximum of a density function is about 1 or so. What I want to do is to configure two plots at the same height, with one y-axis on the left and the other on the right. Can anyone help? Thank you.
Use the prob=TRUE argument to hist:
hist(samples, prob=TRUE)
curve(dfun,add=TRUE)
Also see this SO question
How to plot the density of a single column dataset as dots? For example
x <- c(1:40)
On the same plot using the same scale of the x-axis and y-axis, how to add another data set as line format which represent the density of another data that represents the equation of
y = exp(-x)
to the plot?
The equation is corrected to be y = exp(-x).
So, by doing plot(density(x)) or plot(density(y)), I got two separated figures. How to add them in the same axis and using dots for x, smoothed line for y?
You can add a line to a plot with the lines() function. Your code, modified to do what you asked for, is the following:
x <- 1:40
y <- exp(-x)
plot(density(x), type = "p")
lines(density(y))
Note that we specified the plot to give us points with the type parameter and then added the density curve for y with lines. The help pages for ?plot, ?par, ?lines would be some insightful reading. Also, check out the R Graph Gallery to view some more sophisticated graphs that generally have the source code attached to them.
This question already has an answer here:
How To Avoid Density Curve Getting Cut Off In Plot
(1 answer)
Closed 6 years ago.
newbie here. I have a script to create graphs that has a bit that goes something like this:
png(Test.png)
ht=hist(step[i],20)
curve(insert_function_here,add=TRUE)
I essentially want to plot a curve of a distribution over an histogram. My problem is that the axes limits are apparently set by the histogram instead of the curve, so that the curve sometimes gets out of the Y axis limits. I have played with par("usr"), to no avail. Is there any way to set the axis limits based on the maximum values of either the histogram or the curve (or, in the alternative, of the curve only)?? In case this changes anything, this needs to be done within a for loop where multiple such graphs are plotted and within a series of subplots (par("mfrow")).
Inspired by other answers, this is what i ended up doing:
curve(insert_function_here)
boundsc=par("usr")
ht=hist(A[,1],20,plot=FALSE)
par(usr=c(boundsc[1:2],0,max(boundsc[4],max(ht$counts))))
plot(ht,add=TRUE)
It fixes the bounds based on the highest of either the curve or the histogram.
You could determine the mx <- max(curve_vector, ht$counts) and set ylim=(0, mx), but I rather doubt the code looks like that since [] is not a proper parameter passing idiom and step is not an R plotting function, but rather a model selection function. So I am guessing this is code in Matlab or some other idiom. In R, try this:
set.seed(123)
png("Test.png")
ht=hist(rpois(20,1), plot=FALSE, breaks=0:10-0.1)
# better to offset to include discrete counts that would otherwise be at boundaries
plot(round(ht$breaks), dpois( round(ht$breaks), # plot a Poisson density
mean(ht$counts*round(ht$breaks[-length(ht$breaks)]))),
ylim=c(0, max(ht$density)+.1) , type="l")
plot(ht, freq=FALSE, add=TRUE) # plot the histogram
dev.off()
You could plot the curve first, then compute the histogram with plot=FALSE, and use the plot function on the histogram object with add=TRUE to add it to the plot.
Even better would be to calculate the the highest y-value of the curve (there may be shortcuts to do this depending on the nature of the curve) and the highest bar in the histogram and give this value to the ylim argument when plotting the histogram.