How can i set the origin of coordinates properly in R?
i want the origin of coordinates in my graph,
where x=1 and y=-1 not in common x=0 and y=0 ,please see the attachment.
First of all you should note that R, by default, puts the axes at the side of the plot, not necessarily crossing at [0;0].
What you can do is plotting the graph without axes and add them up later at the desired position using the axis function
x <- -5:5
y <- x
plot(x,y, t="l", xaxt="n", yaxt="n")
axis(1, pos=-1)
axis(2, pos=1, las=1)
See ?axis for more information (you may find the at and labels parameters of axis particularly useful).
Related
I would like to plot two graphs in the same plotting region with horizontal grid lines. Each side of the grid lines should give the value for one graph or the other. There should be no y-axis.
The grid() function allows me to simply set the number of bins using the ny= argument. How do I get the corresponding labels to the grid lines? Usually, I would use axis(..., lwd=0) to get the labels. However, the function requires label positions with at=c() and does not feature a ny= argument. Is there a way to automatically set the locations from the number of bins?
Based on Miff's hint below, this should solve the problem.
plot(1:10, axes=FALSE, ylim=c(0,10), ylab="")
par(yaxp=c(0, 10, 5))
axis(2, lwd=0, col.axis="gray")
par(new=TRUE)
plot(60:50, axes=FALSE, ylim=c(50,60), ylab="")
par(yaxp=c(50, 60, 5))
axis(4, lwd=0, col.axis="gray")
grid(NA, NULL)
grid() gets its locations for gridlines from axTicks(), which in turn uses numbers from par("yaxp"). If you modify this parameter (rather than explicitly passing it to grid), the result will then apply to both the grid drawn and the axis. For example:
plot(1:10, axes=FALSE)
axis(2) #Default 4 sections between ticks
par(yaxp=c(par("yaxp")[1:2], 7)) #Lets have seven instead
axis(4)
grid() #Grid now matches with right rather than left
Obviously similar works for the x axis.
How can one force the visualisation of the zero axes y=0, x=0 in R, removing the external ones siding the plot? I want to obtain the same effect that one can have for example in Gnuplot with set xzeroaxis, set yzeroaxis.
You can do this using by suppressing the default axes by using axes=FALSE and then using axis to draw horizontal and vertical lines to represent the axes.
# example plot
plot(-2:2, -2:2, axes=FALSE)
# add yaxis at position zero and rotate labels 45deg
axis(side=2, pos=0, las=1, lty="dashed")
# x axis
axis(side=1, at=c(-2,-1,1,2), pos=0, lty="dashed")
This produces
Actually, I have solved my own question as follows:
f<-function(x) x^3-2*x
# take the axes off first
plot(f,-2,2, axes=FALSE)
# re-set the axes at a given point (pos=0)
axis(1, pos=0, at=c(-2,-1,0,1,2))
axis(2, pos=0, at=c(-4,-2,2,4))
produces the below, which is what I had in mind (labels and the rest can be then adjusted at will).
Struggling with this one. I have 25 data items that I want plotted with bubbles in 5 columns.
The plot can be re-created thus:
xcord <- c(1,1,1,1,1,2,2,2,2,2,3,3,3,3,3,4,4,4,4,4,5,5,5,5,5)
ycord <- c(1,2,3,4,5,1,2,3,4,5,1,2,3,4,5,1,2,3,4,5,1,2,3,4,5)
zsize <- c(2,1,2,3,6,8,9,1,4,5,5,6,7,8,8,9,5,5,5,5,1,8,1,1,12)
Save the parameters before I change them:
op <- par()
dev.off()
Change the parameters:
par (mfrow=c(1,0), mar=c(2,2,2,2), oma=c(2,2,2,2))
Plot using symbols:
symbols(xcord, ycord, zsize, inches=0.3, fg="white", bg="red", xlab="Events", ylab="Diagnoses", tck=0, xaxt="n", yaxt="n")
mtext("Rheumatic diagnoses by cerebrovasular events", line=2, font=2, cex=1.2)
I am happy with the above plot and deliberately used tck=0, xaxt="n", yaxt="n" to clear the axes. I want to manually overlay custom text, controlled with custom co-ordinates (which work with the sysmbols plot), but have not been able to do it. I have tried some of the par arguments and the axes function.
I also tried leaving the axes on:
symbols(xcord, ycord, zsize, inches=0.3, fg="white", bg="red", xlab="Events", ylab="Diagnoses")
but do not know how to change the output (1,2,3,4,5) to my own custom axes labels.
Thank you.
You are looking for the axis function (see ?axis for details), e.g. to replace the 1:5 with A, B, C, D, E:
axis(side=1, at=1:5, labels=LETTERS[1:5])
For some reason if I try to display data with the following code, I get the axis right, but the actual data does not plot. Any suggestions?
par(bg="lightgray")
adates <-as.Date(row.names(try),format="%Y-%m-%d")
plot(try[,1],x=adates,type="o",axes=FALSE, ann=FALSE)
usr <- par("usr")
rect(usr[1], usr[3], usr[2], usr[4], col="cornsilk", border="black")
lines(try[,1], col="blue")
axis(2,col.axis="blue",,at=pretty(try[,1]),las=1,labels=sprintf("$%1.0f",pretty(try[,1]/1000)),cex.axis=.75)
axis.Date(1, at=pretty(adates), label=format(pretty(adates),"%y"))
box()
title(main="This is a graph", font.main=4, col.main="red",xlab="Date",ylab="$ (in $1000s)")
Forgetting all the other bits of code, take a look at
plot(try[,1],x=adates,type="o",axes=FALSE, ann=FALSE)
The first argument to plot is the vector x-coordinates, which in this case is try[,1]. You then provide another set of x-coordinates with x=adates. So now you have two sets of x-coords but no y-coords.
Hello I am trying to create a stacked barplot using the following code:
test <- as.matrix(read.csv(file="test4.csv",sep=",",head=TRUE))
test <- test[,2:ncol(test)]
pdf(file="test.pdf", height=4, width=6)
par(lwd = 0.3)
barplot(test, space=0.4, xaxt='n', ann=FALSE)
axis(1, cex.axis=0.25, las=2, at=1:ncol(test), space=0.4, labels=colnames(test))
dev.off()
And I get:
As you can see the labels in the x-axis do not match the bars in the plot. Also, the ticks are huge.
Can you guys help me beautify the x axis? Thanks so much
Try storing the returned value of the call to barplot() in a named object, and then passing that in to the at= argument of axis():
xLabLocs <- barplot(test, space=0.4, xaxt='n', ann=FALSE)
axis(1, cex.axis=0.25, las=2, at=xLabLocs,
space=0.4, labels=colnames(test))
This may look odd, but it is explained in the Value section of the ?barplot help file:
Value:
A numeric vector (or matrix, when ‘beside = TRUE’), say ‘mp’,
giving the coordinates of _all_ the bar midpoints drawn, useful
for adding to the graph.
You just made the (easy enough to make) mistake of assuming that the x-axis coordinates of the bar centers are at 1:n, where n is the number of bars. That's not necessarily true, so it's nice that a single call to barplot() will both: (a) plot the bar plot as its side effect; and (b) return the necessary x-axis coordinates as its return value.