I am trying to create an annotation (particularly a rectangle) over a ggplot. Here's what I want to get:
I have tried geom_rect but that can only draw inside the plot axis.
I have also attempted to use annotate_custom which this post mentions, but when I try to work with xmin = -3 (for instance), it doesn't work.
Thank you!
I'm gonna start by asking what you are trying to achieve with this? It seems odd, at least in your example.
But, it can be done. Because you did not provide a reproducible example, I've got something else. The goal here is to turn of the panel's clipping, such that elements that lie outside it's boundaries will be plotted.
library(ggplot2)
library(grid)
# Create a plot
p <- ggplot(mtcars, aes(wt, mpg)) + geom_point()
Here, I'm adding a rectangle with rect. But this also modifies the x- and y-axis, so we fix these with coord_cartesian. You cannot use xlim as this will remove data points that fall outside the range.
g <- p + annotate('rect', xmin=-1, xmax=3, ymin=10, ymax=30, fill='blue', alpha=1/3) +
coord_cartesian(xlim=c(1, 4))
# Convert into a graphical object -- a grob
g <- ggplotGrob(g)
# Try printing g
g is an object that puts all the elements into a table-like structure. So now, we find the panel in the layout dataframe of g, and turn of clipping.
i <- which(g$layout$name == 'panel')
g$layout[i,'clip'] <- 'off'
Finally draw the grob:
# grid.newpage()
grid.draw(g)
Related
library(ggplot2)
p <- ggplot(iris,aes(Sepal.Width,Petal.Length))+
geom_line()
p
Imagine that you have a ggplot object and you have no access to the code or data that created this plot. How does one adjust the size/thickness of the plotted line?
I have tried modifying the theme, but that only changes the background lines and not the plotted lines.
p+
theme(line=element_line(size=10))
You can change or add parameters to a specific layer in a ggplot object like this:
p$layers[[1]]$aes_params$size = 2
p
For more complex ggplots, where you don't know which layers are the geom_line layers, you will have to pick out which layers are geom_line layers to rewrite their aesthetic parameters:
geomlines <- which(sapply(p$layers, function(x) class(x$geom)[1] == "GeomLine"))
p$layers[geomlines] <- lapply(p$layers[geomlines], function(x) {
x$aes_params$size <- 2
x
})
p
I want to make an area plot with ggplot(mpg, aes(x=year,y=hwy, fill=manufacturer)) + geom_area(), but I get this:
I'm realy new in R world, can anyone explain why it does not fill the area between the lines? Thanks!
First of all, there's nothing wrong with your code. It's working as intended and you are correct in the syntax required to do what you are looking to do.
Why don't you get the area geom to plot correctly, then? Simple answer is that you don't have enough points to draw a proper line between your x values for all of the aesthetics (manufacturers). Try the geom_point plot and you'll see what I mean:
ggplot(mpg, aes(x=year,y=hwy)) + geom_point(aes(color=manufacturer))
You need a different dataset. Here's a dummy one that is simply two lines with different slopes. It works as expected because each of the aesthetics has y values which span the x labels:
# dummy dataset
df <- data.frame(
x=rep(1:10,2),
y=c(seq(1,10,length.out=10), seq(1,5,length.out=10)),
z=c(rep('A',10), rep('B', 10))
)
# plot
ggplot(df, aes(x,y)) + geom_area(aes(fill=z))
I am preparing a chart where I have client's requirement to put same legend on top and bottom. Using ggplot I can put it either at top or at bottom. But I am not aware about option of duplicating at both the places.
I have tried putting legend.position as c('top','bottom') but that is giving me error and I know if should give error.
Can it be done with other libraries? I want to same legend twice at top and at bottom?
Take this code for an instance
library(ggplot2)
bp <- ggplot(data=PlantGrowth, aes(x=group, y=weight, fill=group)) + geom_boxplot()
bp <- bp + theme(legend.position="bottom")
bp
You have to work with the intermediate graphic objects (grobs) that ggplot2 uses when being plotted.
I grabbed a function that was flowing around here on StackOverflow to extract the legend, and put it into a package that is now on CRAN.
Here's a solution:
library(lemon)
bp <- bp + theme(legend.position='bottom')
g <- ggplotGrob(bp)
l <- g_legend(g)
grid.arrange(g, top=l)
g_legend accepts both the grob-version (that cannot be manipulated with ggplot2 objects) and the ordinary ggplot2 objects. Using ggplotGrob is a one-way street; once converted you cannot convert it back to ggplot2. But, as in the example, we keep the original ggplot2 object. ;)
Depending on the use case, a center-aligned top legend may not be appropriate as in the contributed answer by #MrGrumble here: https://stackoverflow.com/a/46725487/5982900
Alternatively, you can copy the "guide-box" element of the ggplotGrob, append it to your grob object, and reset the coordinates to the top of the ggplot.
createTopLegend <- function(ggplot, heightFromTop = 1) {
g <- ggplotGrob(ggplot)
nGrobs <- (length(g$grobs))
legendGrob <- which(g$layout$name == "guide-box")
g$grobs[[nGrobs+ 1]] <- g$grobs[[legendGrob]]
g$layout[nGrobs+ 1,] <- g$layout[legendGrob,]
rightLeft <- unname(unlist(g$layout[legendGrob, c(2,4)]))
g$layout[nGrobs+ 1, 1:4] <- c(heightFromTop, rightLeft[1], heightFromTop, rightLeft[2])
g
}
Load the gridExtra package. From your ggplot object bp, use createTopLegend to duplicate another legend, then use grid.draw to produce your final figure. Note you may need to alter your plot margins depending on your figure.
library(ggplot2)
library(grid)
library(gridExtra)
bp <- ggplot(data=PlantGrowth, aes(x=group, y=weight, fill=group)) + geom_boxplot()
bp <- bp + theme(legend.position="bottom", plot.margin = unit(c(2,0,0,0), "lines"))
g <- createTopLegend(bp)
grid.draw(g)
# dev.off()
This will ensure the legend is aligned in the same way horizontally as it appears in your original ggplot.
I would like to change the font size of the labels in this plot:
library(ggplot2)
p <- ggplot(mtcars, aes(x=wt, y=mpg)) +
geom_text(label=rownames(mtcars))
p
My problem: I do not know what the labels are. (I stored a plot in which I used different data.frame()s to add geom_text(). I now only loaded the plot (p in this example), but do not want to also load the data.frame()s with which I created the labels).
As I do not know what the labels are, I cannot use this solution:
p + geom_text(label=rownames(mtcars), size=2)
(Another problem with this solution would be that I still needed to delete the original geom_text() with the larger font-size).
I can change the size of all text in the plot with this solution:
library(grid)
grid.force()
grid.gedit("GRID.text", grep=TRUE, gp=gpar(fontsize=4.5))
However, now also my axes changed, which is not what I wanted.
I believe there are several options to achieve what I want, at least two of which should be fairly simply to implement:
Save the object from grid.gedit() to p1 and then p1 + theme(text = element_text(size=2)). My problem here: I do not know how to save the object from grid.gedit(). This would be my preferred option.
Go to the right viewport before applying grid.gedit(). I tried this, but still change both the labels (which I want) and the axes text (which I do not want).
Somehow extract the data.frame for the labels from the stored plot (p in this example) to apply the solution that I provided first.
You can inspect (/modify) the plot after building it,
library(ggplot2)
p <- ggplot(mtcars, aes(x=wt, y=mpg)) +
geom_text(label=rownames(mtcars))
g <- ggplot_build(p)
# original data is in str(g$plot$data)
# but it's easier to process the data for rendering
g[["data"]][[1]][["size"]] <- 5
g[["data"]][[1]][["colour"]] <- "red"
gg <- ggplot_gtable(g)
grid.newpage()
grid.draw(gg)
Your grid.gedit command was close. You need to set up a gPath so that the edit command finds just those labels in the plot panel. grid.ls(grid.force()) returns a hierarchy of grobs. Find the 'panel', then the 'text'. (Note: the 'g' in 'gedit' stands for 'grep = TRUE, global = TRUE')
library(ggplot2)
p <- ggplot(mtcars, aes(x=wt, y=mpg)) +
geom_text(label=rownames(mtcars))
p
library(grid)
grid.ls(grid.force()) # Locate the path to the labels in the panel
grid.gedit(gPath("panel","GRID.text"), gp=gpar(fontsize=4.5))
If you prefer, with a few more lines of code, the plot object can be edited rather than editing on screen.
g = ggplotGrob(p)
g = editGrob(grid.force(g), gPath("panel", "GRID.text"), grep=TRUE, gp=gpar(fontsize=4.5))
grid.newpage()
grid.draw(g)
What's the ggplot2 equivalent of "dotplot" histograms? With stacked points instead of bars? Similar to this solution in R:
Plot Histogram with Points Instead of Bars
Is it possible to do this in ggplot2? Ideally with the points shown as stacks and a faint line showing the smoothed line "fit" to these points (which would make a histogram shape.)
ggplot2 does dotplots Link to the manual.
Here is an example:
library(ggplot2)
set.seed(789); x <- data.frame(y = sample(1:20, 100, replace = TRUE))
ggplot(x, aes(y)) + geom_dotplot()
In order to make it behave like a simple dotplot, we should do this:
ggplot(x, aes(y)) + geom_dotplot(binwidth=1, method='histodot')
You should get this:
To address the density issue, you'll have to add another term, ylim(), so that your plot call will have the form ggplot() + geom_dotplot() + ylim()
More specifically, you'll write ylim(0, A), where A will be the number of stacked dots necessary to count 1.00 density. In the example above, the best you can do is see that 7.5 dots reach the 0.50 density mark. From there, you can infer that 15 dots will reach 1.00.
So your new call looks like this:
ggplot(x, aes(y)) + geom_dotplot(binwidth=1, method='histodot') + ylim(0, 15)
Which will give you this:
Usually, this kind of eyeball estimate will work for dotplots, but of course you can try other values to fine-tune your scale.
Notice how changing the ylim values doesn't affect how the data is displayed, it just changes the labels in the y-axis.
As #joran pointed out, we can use geom_dotplot
require(ggplot2)
ggplot(mtcars, aes(x = mpg)) + geom_dotplot()
Edit: (moved useful comments into the post):
The label "count" it's misleading because this is actually a density estimate may be you could suggest we changed this label to "density" by default. The ggplot implementation of dotplot follow the original one of Leland Wilkinson, so if you want to understand clearly how it works take a look at this paper.
An easy transformation to make the y axis actually be counts, i.e. "number of observations". From the help page it is written that:
When binning along the x axis and stacking along the y axis, the numbers on y axis are not meaningful, due to technical limitations of ggplot2. You can hide the y axis, as in one of the examples, or manually scale it to match the number of dots.
So you can use this code to hide y axis:
ggplot(mtcars, aes(x = mpg)) +
geom_dotplot(binwidth = 1.5) +
scale_y_continuous(name = "", breaks = NULL)
I introduce an exact approach using #Waldir Leoncio's latter method.
library(ggplot2); library(grid)
set.seed(789)
x <- data.frame(y = sample(1:20, 100, replace = TRUE))
g <- ggplot(x, aes(y)) + geom_dotplot(binwidth=0.8)
g # output to read parameter
### calculation of width and height of panel
grid.ls(view=TRUE, grob=FALSE)
real_width <- convertWidth(unit(1,'npc'), 'inch', TRUE)
real_height <- convertHeight(unit(1,'npc'), 'inch', TRUE)
### calculation of other values
width_coordinate_range <- diff(ggplot_build(g)$panel$ranges[[1]]$x.range)
real_binwidth <- real_width / width_coordinate_range * 0.8 # 0.8 is the argument binwidth
num_balls <- real_height / 1.1 / real_binwidth # the number of stacked balls. 1.1 is expanding value.
# num_balls is the value of A
g + ylim(0, num_balls)
Apologies : I don't have enough reputation to 'comment'.
I like cuttlefish44's "exact approach", but to make it work (with ggplot2 [2.2.1]) I had to change the following line from :
### calculation of other values
width_coordinate_range <- diff(ggplot_build(g)$panel$ranges[[1]]$x.range)
to
### calculation of other values
width_coordinate_range <- diff(ggplot_build(g)$layout$panel_ranges[[1]]$x.range)