Plotting a grid behind data, not in front in R - r

I like to produce my own grid lines when plotting so I can control tick marks, etc. and I am struggling with this with the 'hist' plotting routine.
hist(WindSpeed, breaks=c(0:31), freq=TRUE, col="blue", xaxt="n", yaxt="n", xlab="Wind Speed (m/s)",main="Foo", cex.main=1.5, cex.axis=1, cex.lab=1, tck=1, font.lab=2)
axis(1, tck=1, ,col.ticks="light gray")
axis(1, tck=-0.015, col.ticks="black")
axis(2, tck=1, col.ticks="light gray", lwd.ticks="1")
axis(2, tck=-0.015)
minor.tick(nx=5, ny=2, tick.ratio=0.5)
box()
Plot:
I have then just been able to use the 'lines' or 'points' command to replot the data over top for other types of plots, but with the histogram its not so easy.
Any help would be great.
I added my code below and image based upon John's response...
I added my code below and image based upon John's response...
hist(WindSpeed, breaks=30, freq=TRUE, col="blue", xaxt="n", yaxt="n", xlab="Wind Speed (m/s)",main="Foo", cex.main=1.5, cex.axis=1, cex.lab=1, font.lab=2)
axis(1, tck=1, col.ticks="light gray")
axis(1, tck=-0.015, col.ticks="black")
axis(2, tck=1, col.ticks="light gray", lwd.ticks="1")
axis(2, tck=-0.015)
minor.tick(nx=5, ny=2, tick.ratio=0.5)
box()
hist(WindSpeed, add=TRUE, breaks=30, freq=TRUE, col="blue", xaxt="n", yaxt="n", xlab="Wind Speed (m/s)", main="Foo", cex.main=1.5, cex.axis=1, cex.lab=1, font.lab=2)

Actually, R has a way to do this! It's the panel.first argument to plot.default, which hist calls to do most of the work. It takes an expression which is evaluated "after the plot axes are set up but before any plotting takes place. This can be useful for drawing background grids or scatterplot smooths," to quote from ?plot.default.
hist(WindSpeed, breaks=c(0:31), freq=TRUE, col="blue", xaxt="n", yaxt="n",
xlab="Wind Speed (m/s)", main="Foo",
cex.main=1.5, cex.axis=1, cex.lab=1, tck=1, font.lab=2,
panel.first={
axis(1, tck=1, col.ticks="light gray")
axis(1, tck=-0.015, col.ticks="black")
axis(2, tck=1, col.ticks="light gray", lwd.ticks="1")
axis(2, tck=-0.015)
minor.tick(nx=5, ny=2, tick.ratio=0.5)
box()
})
See How do I draw gridlines using abline() that are behind the data? for another question that uses this method.

This is relatively easy.
Generate the histogram but don't plot it.
h <- hist(y, plot = FALSE)
Now generate your base plot... I've added some features to make it look more like a standard historgram
plot(h$mids, h$counts, ylim = c(0, max(h$counts)), xlim = range(h$mids)*1.1,
type = 'n', bty = 'n', xlab = 'y', ylab = 'Counts', main = 'Histogram of y')
add your grid
grid()
add your histogram
hist(y, add = TRUE)
Or, as I discovered through this process... you can do it even easier
hist(y)
grid()
hist(y, add = TRUE, col = 'white')
This last method is just redrawing the histogram over the grid.

In R, order matters when you plot. As you've discovered, adding things to a plot adds on top of what you've plotted before. So we need a way to plot the grid first and then the histogram. Try something like this:
plot(1:10,1:10,type = "n")
grid(10,10)
hist(rnorm(100,5,1),add = TRUE)
I haven't recreated your example, since it isn't reproducible, but this general idea should work. But the key idea is to create an empty plot with the correct dimensions using the type = "n" option to plot, then add the grid, then add the histogram using the add = TRUE argument.
Note that the add argument is actually for plot.histogram, hist passes it along via ....

The base graphics solution suggested by #joran is fine. Alternatives:
d <- data.frame(x=rnorm(1000))
library(lattice)
histogram(~x,data=d,panel=function(...) {
panel.grid(...)
panel.histogram(...) }
)
Or:
library(ggplot2)
qplot(x,data=d,geom="histogram",binwidth=0.1)+theme_bw()+
labs(x="Wind speed", y="Frequency")
(But of course you will have to learn all the details of adjusting labels, titles, etc. ... I'm not actually sure how to do titles in ggplot ...)

Another methods for grid lines in background:
A)
hist( y, panel.first=grid() ) # see: help( plot.default )
box()
B)
plot.new() # new empty plot
nv <- length( pretty(x) ) - 1 # number of vertical grid lines (or set by hand)
nh <- length( pretty(y) ) - 1 # number of horizontal grid lines (or set by hand)
grid( nx = nv, ny = nh ) # preplot grid lines
par( new = TRUE ) # add next plot
plot( x, y ) # plot or hist, etc
box() # if plot hist
Arbitrary lines in background with abline:
C)
How do I draw gridlines using abline() that are behind the data?
D)
# first, be sure there is no +/-Inf, NA, NaN in x and y
# then, make the container plot with two invisible points:
plot( x = range( pretty( x ) ), y = range( pretty( y ) ), type = "n", ann = FALSE )
abline( h = hlines, v = vlines ) # draw lines. hlines, vlines: vectors of coordinates
par( new = TRUE ) # add next plot. It is not necessary with points, lines, segments, ...
plot( x, y ) # plot, hist, etc
box() # if plot hist

Related

how to plot matlab style log-log plot using R plot

ENV
R version 3.3.1
MAC OSX 10.9.4
I would like to plot a style like figure below, which is plotted by matlab.
There is full grid on the plot with customized axis range (e.g. $10^0~10^{-4}$) and axis label (e.g. 10^0 10^1 10^-2 10^-3 10^-4 10^-5). There are ten ticks between 10^0 and 10^1 and also other labels. Similar for y axis.
Expected:
I tried:
initial.dir<-getwd()
setwd("/Rworks/bin")
sink("r.o")
pk <- read.table("2017.file)
rownames(pk)<-c("k","pk")
d.f <- data.frame(t(pk))
png(file="m.png")
plot(
d.f$k,
d.f$pk,
type = "n",
log = "xy",
xlim = c( 10^0, 10^2),
ylim = c( 0.00001, 1),
)
lines( d.f$k, d.f$pk, col = "green4", lty = "dotted")
points( d.f$k, d.f$pk, bg = "limegreen", pch = 21 )
box()
dev.off
sink()
setwd(initial.dir)
I got:
The axis and axis label and the ticks and grid is not what I want. Can anyone can give an advices? Thanks.
Worst case scenario, you can just draw the axes and background lines yourself.
plot(
x=c(1,2), y=c(0.6,0.2),
pch=21, bg="red",
log = "xy",
xlim = c( 10^0, 10^2),
ylim = c( 0.00001, 1),
xaxt="n", yaxt="n",
xlab="", ylab="",
yaxs="i"
)
lines(x=c(1,2), y=c(0.6,0.2))
axis(1, at=10^(0:2),
labels=expression(10^0, 10^1, 10^2))
axis(2, at=10^(-5:0), las=1,
labels=expression(10^-5, 10^-4, 10^-3, 10^-2, 10^-1, 10^0))
abline(h=outer((1:10),(10^(-5:-1))), col="#00000033", lty=2)
abline(v=outer((1:10),(10^(0:1))), col="#00000033", lty=2)
Here's an example - it's not exactly what you want (e.g. you could play around with theme options such as panel.grid.minor to get dotted grid lines), but it's most of the way there.
Exponential-format axis tick labels, from here:
fancy_scientific <- function(l) {
# turn in to character string in scientific notation
l <- format(l, scientific = TRUE)
# quote the part before the exponent to keep all the digits
l <- gsub("^(.*)e", "'\\1'e", l)
# turn the 'e+' into plotmath format
l <- gsub("e", "%*%10^", l)
# return this as an expression
parse(text=l)
}
Manual ticks from #G5W's answer: might be possible to write a function to do this automatically, or one might exist somewhere.
yticks = outer((1:10),(10^(-5:-1)))
xticks = outer((1:10),(10^(0:1)))
Draw the plot (with #G5W's sample mini-data)
library(ggplot2)
ggplot(data.frame(x=1:2,y=c(0.6,0.2)),
aes(x,y))+
geom_point(colour="red")+
scale_x_log10(limits=c(1,100),labels=fancy_scientific,
minor_breaks=xticks)+
scale_y_log10(limits=c(1e-5,1),labels=fancy_scientific,
minor_breaks=yticks)+
theme_bw()

R horizontal barplot with aligned plot ontop

I am having trouble getting the spacing right on a plot on top of a horizontal barplot. It is the same general issue as described here:
http://www.r-bloggers.com/adding-lines-or-points-to-an-existing-barplot/
But I am trying to use "plot" instead of "points" or "lines". Is there a trick for using plot to get the spacing of the bars and the points to match?
Code:
barplot(df$DIC_mM,col=scalegreen, xlab="DIC mM", horiz=TRUE, xlim=c(0,0.7),
col.axis="white", col.lab="white", axes=FALSE, border="white")
axis(1,line=1,col="white",col.ticks="white",col.axis="white")
par(new = TRUE)
plot(df$d13DIC,df$Order, type="p", axes = FALSE, bty = "n", xlab ="",
col="deepskyblue2", lwd=5, xlim=c(-50,170), lend=2, col.lab="white", ylab="")
axis(3,at = c(-50,0,50,100,150), line=1, col="deepskyblue2", col.ticks="deepskyblue2",
col.axis="deepskyblue2")
mtext(expression(paste(delta ^{13},'DIC'," \u0028","\u2030","\u0029")), 3,
line=-0.5,at=50,col="deepskyblue2", cex=0.75)
Is there a reason why you don't want to use points to add the points? If you're willing to use points you can do it like this:
Create barplot and save the y-coordinates of the bars to y. You haven't provided sample data, so I'll use the built-in mtcars data frame:
y = barplot(mtcars$mpg[1:10], horiz=TRUE)
Now add the points. We use y as the y values, because those are the coordinates of the midpoints of each bar:
points(sqrt(mtcars$mpg[11:20]), y, col="red", pch=16, cex=2)
When you use par(new=TRUE) and then call plot again, you're overlaying a new plot with a new coordinate system that in general will be different from the original coordinate system.
This is what worked, based on this post suggested by eipi10: midpoints returned by barplot function do not actually line up with midpoints of bars
mp<-barplot(df$DIC_mM,col=scalegreen, xlab="DIC mM", horiz=TRUE, xlim=c(0,0.7), col.axis="white", col.lab="white", axes=FALSE, border="white", ylim=c(0,length(df$DIC_mM)+2))
axis(1,line=1,col="white",col.ticks="white",col.axis="white")
par(new = TRUE)
plot(df$d13DIC, mp, type="p", axes = FALSE, bty = "n", xlab ="",col="deepskyblue2", lwd=5, xlim=c(-50,170), lend=2, col.lab="white", ylab="", ylim=c(0,length(df$DIC_mM)+2))
axis(3,at = c(-50,0,50,100,150),line=1,col="deepskyblue2",col.ticks="deepskyblue2",col.axis="deepskyblue2")
mtext(expression(paste(delta ^{13},'DIC'," \u0028","\u2030","\u0029")),3,line=-0.5,at=50,col="deepskyblue2", cex=0.75)

Altering the margins of a legend in R

I am very new to R, so I'm struggling here a bit and I haven't found an answer to my problem.
I'm trying to produce a simple bar-chart in R, and I have set my x-axis variable labels to be vertical, using las=2. I then changed the margins for the barplot so that the labels would not overlap the xlab label, using par(mar=c(20,15,5,3)) and par(mgp=c(6,1,0)).
I would like to add a legend to this, but the one I have has adopted the margin dimensions of the graph itself, so that it appears too big and does not fit. I tried using cex but that only affects the text in the legend. Is there anyway for me to change the legend margins (or the graph margins) independently?
Here's what I have coded:
par(mar=c(20,15,5,3))
par(mgp=c(6,1,0))
par(xpd=TRUE)
barplot(
names.arg=c("Africa", "Central America, South America, Caribbean",
"Middle East", "Central and Eastern Europe",
"South and East Asia"),
cex.names=0.8, las=2, t(YLL),
ylab="Percentage (%)", ylim=c(0,100), main="", beside=TRUE,
col= c("green4", "orange"),xlab="Regions", mar=c(20,15,5,3)
)
legend(
10, 100,
legend=c("Communicable diseases", "Communicable diseases"),
fill= c("green4", "orange"), cex=0.7
)
I will really appreciate the help, thanks.
You can also use the arguments of legend function: y.intersp, x.intersp and text.width for reduce the size of the legend.
Here an example:
set.seed(55) # Set the seed of R‘s random number generator
x <- 1:10
y <- runif(10, min=0, max=100) # Generating random numbers
z <- runif(10, min=0, max=100) # Generating random numbers
plot(x,y, type="l", ylim=c(0,100), ylab="y and z")
par(new=TRUE)
plot(x,z, type="l", col="red", ylim=c(0,100), ylab=NA, xaxt='n', yaxt='n')
legend("topright", c("y","z"), lty="solid", col=c("black", "red"))
And same code modifiying the legend function:
set.seed(55) # Set the seed of R‘s random number generator
x <- 1:10
y <- runif(10, min=0, max=100) # Generating random numbers
z <- runif(10, min=0, max=100) # Generating random numbers
plot(x,y, type="l", ylim=c(0,100), ylab="y and z")
par(new=TRUE)
plot(x,z, type="l", col="red", ylim=c(0,100), ylab=NA, xaxt='n', yaxt='n')
legend("topright", c("y","z"), lty="solid", col=c("black", "red"), y.intersp=0.5,x.intersp=0.5,text.width=0.1)
I don't know if I understood your problem correctly, but maybe you can try x.intersp or y.intersp to modify the spacing in the x and y axis of your legend. For example, you could add x.intersp=0.5 to bring the elements of your legend closer in the x axis.
If this does not work and you provide a screenshot, maybe I could try to help you better.

Arrange points and lines in an r plot legend

Is it possible to rearrange the legend of the following plot
plot(1,1, type="n")
legend("topleft", c("1", "2"), col=c("darkblue", "darkred"), pch = 1, bty = "n", horiz = T, lwd=1.25, cex=1.8)
to look like this ("point-line-point" pattern)?
Usually, if you want this level of control over plot elements, you'll have to do it manually with primitives (points(), lines()/segments(), text(), etc.) and careful calculations from the plot parameters (e.g. par('usr')). It's not easy. Here's an example of how this could be done:
point.line.point <- function(x1,y1,x2=x1,y2=y1,...) {
points(c(x1,x2),c(y1,y2),...);
segments(x1,y1,x2,y2,...);
};
legend.plp <- function(x,y,labels,col,linewidth=diff(par('usr')[1:2])/10,textgap=diff(par('usr')[1:2])/20,...) {
comb <- cbind(labels,col);
xc <- x;
for (i in seq_len(nrow(comb))) {
x2 <- xc+linewidth;
point.line.point(xc,y,x2,col=comb[i,'col'],...);
text(x2+textgap,y,comb[i,'labels'],...);
xc <- x2+textgap*1.5+strwidth(comb[i,'labels']);
};
};
plot(1,1,type="n");
legend.plp(par('usr')[1]+diff(par('usr')[1:2])/20,par('usr')[4]-diff(par('usr')[3:4])/20,1:2,c('darkblue','darkred'),font=2,cex=1.5);
Here is an alternative solution that is the opposite of elegant. It involves embedding a couple of plots (one per legend), and a great deal of manual manipulation (to set the 'legends' where you want them to be):
library(Hmisc)
data(mtcars)
#plots the one in blue
plot(mtcars$cyl, type="o", col="darkblue")
#plots the one in red
lines(mtcars$carb, type="o", col="darkred")
#name the legends
text(6.5,7, "Cyl", font=2)
text(14,7, "Carb", font=2)
#add the subplots, it's actually a normal plot wrapped around the subplot with the x and y positions
subplot(plot(c(1,0),c(1,1), xlab=NA, ylab=NA, xaxt="n", yaxt="n", col="darkblue", type="o", axes=FALSE), 3, 7)
subplot(plot(c(1,0),c(1,1), xlab=NA, ylab=NA, xaxt="n", yaxt="n", col="darkred", type="o", axes=FALSE), 10, 7)
That yields the following plot:

Adding label to secondary axis in R

I have this code:
# Plotting everything
plot( p1, col= "lightgreen", xlim=c(-2.5,4.5), ylim=c(0, 700), main="Daily Total Precipitation for AR and Oct-May", xlab="ln(x)" , ylab="Frequency", xaxt = "n") # first histogram
plot( p2, col="red", xlim=c(-2.5,4.5), ylim=c(0, 700), xaxt = "n" , add=T)
# Adding in text labels on top of the bars
text(x, y, paste(round(percents,2),"%"), cex=0.50, pos=3, offset=0.3, col="black")
axis(side=1, at=breaks) # new x-axis
# parameter that needs to be set to add a new graph on top of the other ones
par(new=T)
plot(x, percents, xlim=c(-2.5,4.5), type="l", col="yellow", lwd=3.0, axes=F, ylab=NA, xlab=NA)
axis(side=4, at=seq(0,100,by=10), col="yellow", col.axis="yellow") # additional y-axis
mtext("Percent", side=4, col="yellow")
# legend settings
legend("topleft", c("AR", "Oct-May"), lwd=10, col=c("red", "lightgreen"))
Which produces this graph:
And I can't seem to figure out how to get the secondary y-axis label to show up in the correct position. Any help or suggestions is greatly appreciated.
Edit: Using RStudio.
One option is to specify the line argument to mtext(). In the example below I add a couple more lines to the right (side = 4) margin of the plot using par(), and then I draw three labels using mtext() at the default (line = 0), line 3 (line = 3), and line -3 (line = -3):
op <- par(mar = c(5,4,4,4) + 0.1)
plot(1:10)
mtext("line0", side = 4)
mtext("line3", side = 4, line = 3)
mtext("line-3", side = 4, line = -3)
par(op)
Note that line numbers increase away from the plot region and that negative line values move into the plot region, or to the left of the right boundary of the plot region.
It takes a little playing with the number of margin lines (as set in par(mar = x)) and which line you want to draw on using mtext(), but a little trial and error should get you what you want.
Note also that you don't need to specify integer values for the line argument. You can specify fractions of lines too: line = 2.5.

Resources