R: overlying trajectory plot and scatter plot - r

I'm working with ggplot2 and trajectory plots, plots whom are like scatter plots, but with lines that connect points due a specific rule.
My goal is to overlay a trajectory plot with a scatter plot, and each of them has different data.
First of all, the data:
# first dataset
ideal <- data.frame(ideal=c('a','b')
,x_i=c(0.3,0.8)
,y_i=c(0.11, 0.23))
# second dataset
calculated <- data.frame(calc = c("alpha","alpha","alpha")
,time = c(1,2,3)
,x_c = c(0.1,0.9,0.3)
,y_c = c(0.01,0.26,0.17)
)
Creating a scatter plot with the first one is easy:
library(ggplot2)
ggplot(calculated, aes(x=x_c, y=y_c)) + geom_point()
After that, I created the trajectory plot, using this helpful link:
library(grid)
library(data.table)
qplot(x_c, y_c, data = calculated, color = calc, group = calc)+
geom_path (linetype=1, size=0.5, arrow=arrow(angle=15, type="closed"))+
geom_point (data = calculated, colour = "red")+
geom_point (shape=19, size=5, fill="black")
With this result:
How can I overlay the ideal data to this trajectory plot (without trajectory of course, they should be only points)?
Thanks in advance!

qplot isn't usually recommended. Here's how you could plot the two dataframes. However, ggplot might work better for you if the dataframes were merged, and you had an x and y column, with an additional method column containing with calculated or ideal.
library(ggplot2)
ideal <- data.frame(ideal=c('a','b')
,x_i=c(0.3,0.8)
,y_i=c(0.11, 0.23)
)
# second dataset
calculated <- data.frame(calc = c("alpha","alpha","alpha")
,time = c(1,2,3)
,x_c = c(0.1,0.9,0.3)
,y_c = c(0.01,0.26,0.17)
)
ggplot(aes(x_c, y_c, color = "calculated"), data = calculated) +
geom_point( size = 5) +
geom_path (linetype=1, size=0.5, arrow = arrow(angle=15, type="closed"))+
geom_point(aes(x_i, y_i, color = "ideal"), data = ideal, size = 5) +
labs(x = "x", y = "y", color = "method")

Related

How to overlay density ggplots from different datasets in R?

I have three ggplots (g1, g2, g3).
They are all from different datasets, and they each have the same xlim and ylim.
I would like to plot them all on one page and overlay them.
I have only found resources online explaining how to plot multiple density plots from the same dataset on the same page.
Is there code I can write so that all subsequent plots are plotted on the same page?
As #Phil pointed out you can't overlay different plots. However, you can make one plot containing all three density plots. (; Using mtcars and mpg as example datasets try this:
library(ggplot2)
ggplot() +
geom_density(aes(mpg, fill = "data1"), alpha = .2, data = mtcars) +
geom_density(aes(hwy, fill = "data2"), alpha = .2, data = mpg) +
scale_fill_manual(name = "dataset", values = c(data1 = "red", data2 = "green"))

Overlay two density plots in plotly

I have a dataset which contains two columns.
Each row is a user with frequency (1~31, shows how frequently a user plays a game monthly) and is_consumed(0,1 whether the user ever consumed in the game).
I want to draw two density plots for frequency separated by the value of is_consumed.
I finished it in ggplot2 but I want to use plotly.
ggplot2 code:
p2 <- p_plot %>%
ggplot(aes(frequency, fill = is_consumed)) +
geom_density(alpha = 0.5)
p2
Output
Red is the density plot of is_consumed == 1. Green is is_consumed == 0
There's a cool function in the plotly library called ggplotly() that converts a ggplot object into a plotly object: https://plot.ly/ggplot2/geom_density/
So you could do:
library(plotly)
library(ggplot2)
p_plot <- data.frame(frequency = c(rnorm(31, 1), rnorm(31)),
is_consumed = factor(round(runif(62))))
p2 <- p_plot %>%
ggplot(aes(frequency, fill = is_consumed)) +
geom_density(alpha = 0.5)
ggplotly(p2)

How to plot histograms of raw data on the margins of a plot of interpolated data

I would like to show in the same plot interpolated data and a histogram of the raw data of each predictor. I have seen in other threads like this one, people explain how to do marginal histograms of the same data shown in a scatter plot, in this case, the histogram is however based on other data (the raw data).
Suppose we see how price is related to carat and table in the diamonds dataset:
library(ggplot2)
p = ggplot(diamonds, aes(x = carat, y = table, color = price)) + geom_point()
We can add a marginal frequency plot e.g. with ggMarginal
library(ggExtra)
ggMarginal(p)
How do we add something similar to a tile plot of predicted diamond prices?
library(mgcv)
model = gam(price ~ s(table, carat), data = diamonds)
newdat = expand.grid(seq(55,75, 5), c(1:4))
names(newdat) = c("table", "carat")
newdat$predicted_price = predict(model, newdat)
ggplot(newdat,aes(x = carat, y = table, fill = predicted_price)) +
geom_tile()
Ideally, the histograms go even beyond the margins of the tileplot, as these data points also influence the predictions. I would, however, be already very happy to know how to plot a histogram for the range that is shown in the tileplot. (Maybe the values that are outside the range could just be added to the extreme values in different color.)
PS. I managed to more or less align histograms to the margins of the sides of a tile plot, using the method of the accepted answer in the linked thread, but only if I removed all kind of labels. It would be particularly good to keep the color legend, if possible.
EDIT:
eipi10 provided an excellent solution. I tried to modify it slightly to add the sample size in numbers and to graphically show values outside the plotted range since they also affect the interpolated values.
I intended to include them in a different color in the histograms at the side. I hereby attempted to count them towards the lower and upper end of the plotted range. I also attempted to plot the sample size in numbers somewhere on the plot. However, I failed with both.
This was my attempt to graphically illustrate the sample size beyond the plotted area:
plot_data = diamonds
plot_data <- transform(plot_data, carat_range = ifelse(carat < 1 | carat > 4, "outside", "within"))
plot_data <- within(plot_data, carat[carat < 1] <- 1)
plot_data <- within(plot_data, carat[carat > 4] <- 4)
plot_data$carat_range = as.factor(plot_data$carat_range)
p2 = ggplot(plot_data, aes(carat, fill = carat_range)) +
geom_histogram() +
thm +
coord_cartesian(xlim=xrng)
I tried to add the sample size in numbers with geom_text. I tried fitting it in the far right panel but it was difficult (/impossible for me) to adjust. I tried to put it on the main graph (which would anyway probably not be the best solution), but it didn’t work either (it removed the histogram and legend, on the right side and it did not plot all geom_texts). I also tried to add a third row of plots and writing it there. My attempt:
n_table_above = nrow(subset(diamonds, table > 75))
n_table_below = nrow(subset(diamonds, table < 55))
n_table_within = nrow(subset(diamonds, table >= 55 & table <= 75))
text_p = ggplot()+
geom_text(aes(x = 0.9, y = 2, label = paste0("N(>75) = ", n_table_above)))+
geom_text(aes(x = 1, y = 2, label = paste0("N = ", n_table_within)))+
geom_text(aes(x = 1.1, y = 2, label = paste0("N(<55) = ", n_table_below)))+
thm
library(egg)
pobj = ggarrange(p2, ggplot(), p1, p3,
ncol=2, widths=c(4,1), heights=c(1,4))
grid.arrange(pobj, leg, text_p, ggplot(), widths=c(6,1), heights =c(6,1))
I would be very happy to receive help on either or both tasks (adding sample size as text & adding values outside plotted range in a different color).
Based on your comment, maybe the best approach is to roll your own layout. Below is an example. We create the marginal plots as separate ggplot objects and lay them out with the main plot. We also extract the legend and put it outside the marginal plots.
Set-up
library(ggplot2)
library(cowplot)
# Function to extract legend
#https://github.com/hadley/ggplot2/wiki/Share-a-legend-between-two-ggplot2-graphs
g_legend<-function(a.gplot){
tmp <- ggplot_gtable(ggplot_build(a.gplot))
leg <- which(sapply(tmp$grobs, function(x) x$name) == "guide-box")
legend <- tmp$grobs[[leg]]
return(legend) }
thm = list(theme_void(),
guides(fill=FALSE),
theme(plot.margin=unit(rep(0,4), "lines")))
xrng = c(0.6,4.4)
yrng = c(53,77)
Plots
p1 = ggplot(newdat, aes(x = carat, y = table, fill = predicted_price)) +
geom_tile() +
theme_classic() +
coord_cartesian(xlim=xrng, ylim=yrng)
leg = g_legend(p1)
p1 = p1 + thm[-1]
p2 = ggplot(diamonds, aes(carat)) +
geom_line(stat="density") +
thm +
coord_cartesian(xlim=xrng)
p3 = ggplot(diamonds, aes(table)) +
geom_line(stat="density") +
thm +
coord_flip(xlim=yrng)
plot_grid(
plot_grid(plotlist=list(p2, ggplot(), p1, p3), ncol=2,
rel_widths=c(4,1), rel_heights=c(1,4), align="hv", scale=1.1),
leg, rel_widths=c(5,1))
UPDATE: Regarding your comment about the space between the plots: This is an Achilles heel of plot_grid and I don't know if there's a way to fix it. Another option is ggarrange from the experimental egg package, which doesn't add so much space between plots. Also, you need to save the output of ggarrange first and then lay out the saved object with the legend. If you run ggarrange inside grid.arrange you get two overlapping copies of the plot:
# devtools::install_github('baptiste/egg')
library(egg)
pobj = ggarrange(p2, ggplot(), p1, p3,
ncol=2, widths=c(4,1), heights=c(1,4))
grid.arrange(pobj, leg, widths=c(6,1))

how to combine in ggplot line / points with special values?

I'm quite new to ggplot but I like the systematic way how you build your plots. Still, I'm struggeling to achieve desired results. I can replicate plots where you have categorical data. However, for my use I often need to fit a model to certain observations and then highlight them in a combined plot. With the usual plot function I would do:
library(splines)
set.seed(10)
x <- seq(-1,1,0.01)
y <- x^2
s <- interpSpline(x,y)
y <- y+rnorm(length(y),mean=0,sd=0.1)
plot(x,predict(s,x)$y,type="l",col="black",xlab="x",ylab="y")
points(x,y,col="red",pch=4)
points(0,0,col="blue",pch=1)
legend("top",legend=c("True Values","Model values","Special Value"),text.col=c("red","black","blue"),lty=c(NA,1,NA),pch=c(4,NA,1),col=c("red","black","blue"),cex = 0.7)
My biggest problem is how to build the data frame for ggplot which automatically then draws the legend? In this example, how would I translate this into ggplot to get a similar plot? Or is ggplot not made for this kind of plots?
Note this is just a toy example. Usually the model values are derived from a more complex model, just in case you wante to use a stat in ggplot.
The key part here is that you can map colors in aes by giving a string, which will produce a legend. In this case, there is no need to include the special value in the data.frame.
df <- data.frame(x = x, y = y, fit = predict(s, x)$y)
ggplot(df, aes(x, y)) +
geom_line(aes(y = fit, col = 'Model values')) +
geom_point(aes(col = 'True values')) +
geom_point(aes(col = 'Special value'), x = 0, y = 0) +
scale_color_manual(values = c('True values' = "red",
'Special value' = "blue",
'Model values' = "black"))

Conditional graphing and fading colors

I am trying to create a graph where because there are so many points on the graph, at the edges of the green it starts to fade to black while the center stays green. The code I am currently using to create this graph is:
plot(snb$px,snb$pz,col=snb$event_type,xlim=c(-2,2),ylim=c(1,6))
I looked into contour plotting but that did not work for this. The coloring variable is a factor variable.
Thanks!
This is a great problem for ggplot2.
First, read the data in:
snb <- read.csv('MLB.csv')
With your data frame you could try plotting points that are partly transparent, and setting them to be colored according to the factor event_type:
require(ggplot2)
p1 <- ggplot(data = snb, aes(x = px, y = py, color = event_type)) +
geom_point(alpha = 0.5)
print(p1)
and then you get this:
Or, you might want to think about plotting this as a heatmap using geom_bin2d(), and plotting facets (subplots) for each different event_type, like this:
p2 <- ggplot(data = snb, aes(x = px, y = py)) +
geom_bin2d(binwidth = c(0.25, 0.25)) +
facet_wrap(~ event_type)
print(p2)
which makes a plot for each level of the factor, where the color will be the number of data points in each bins that are 0.25 on each side. But, if you have more than about 5 or 6 levels, this might look pretty bad. From the small data sample you supplied, I got this
If the levels of the factors don't matter, there are some nice examples here of plots with too many points. You could also try looking at some of the examples on the ggplot website or the R cookbook.
Transparency could help, which is easily achieved, as #BenBolker points out, with adjustcolor:
colvect = adjustcolor(c("black", "green"), alpha = 0.2)
plot(snb$px, snb$pz,
col = colvec[snb$event_type],
xlim = c(-2,2),
ylim = c(1,6))
It's built in to ggplot:
require(ggplot2)
p <- ggplot(data = snb, aes(x = px, y = pz, color = event_type)) +
geom_point(alpha = 0.2)
print(p)

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