CODEWITHSUNDEEP
rggplot2
user3022875
user3022875

Reputation: 9018

R highlight a point on a line

Here is my code that produces a plot. You can run it:

library(ggplot2)
library(grid)
time <- c(87,87.5, 88,87,87.5,88)
value <- c(10.25,10.12,9.9,8,7,6)
variable <-c("a","a","a","b","b","b")
PointSize <-c(5,5,5,5,5,5)
ShapeType <-c(10,10,10,10,10,10)

stacked <- data.frame(time, value, variable, PointSize, ShapeType)

stacked$PointSize <- ifelse(stacked$time==88, 8, 5)
stacked$ShapeType <- ifelse(stacked$time==88, 16,10)

MyPlot <- ggplot(stacked, aes(x=time, y=value, colour=variable, group=variable)) + geom_line() + xlab("Strike") + geom_point(aes(shape = ShapeType, size = PointSize)) + theme(axis.text.x = element_text(angle = 90, hjust = 1), axis.text = element_text(size = 10),   axis.title=element_text(size=14),  plot.title = element_text(size = rel(2)) ,  legend.position = "bottom", legend.text = element_text(size = 10), legend.key.size = unit(1, "cm") ) + scale_shape_identity(guide="none")+scale_size_identity(guide="none")

MyPlot

The plot that is produced highlight the point on the line where the time = 88.

I want to also highlight the point on the the line where the time = 87.925

Is this possible? The thing is that I do not have corresponding value for that time. IS there a way to just find put the point on the lines where time = 87.925 or does some interpolation need to take place so I can get a a value for that time?

Thank you!

Upvotes: 0

Views: 1420

Answers (2)

Jaap
Jaap

Reputation: 83275

Instead of using a point for highlighting the 87.925 value for time, you can also use a vertical line:

ggplot(stacked, aes(x=time, y=value, colour=variable, group=variable)) +
  geom_line() +
  geom_point(aes(shape = ShapeType, size = PointSize)) +
  geom_vline(aes(xintercept=87.925)) +
  xlab("Strike") +
  theme(axis.text.x = element_text(angle = 90, hjust = 1), axis.text = element_text(size = 10),
        axis.title=element_text(size=14), plot.title = element_text(size = rel(2)), legend.position = "bottom",
        legend.text = element_text(size = 10), legend.key.size = unit(1, "cm")) +
  scale_shape_identity(guide="none") +
  scale_size_identity(guide="none")

the result: enter image description here

Update: you can add short lines with geom_segment. Replace geom_vline with

geom_segment(aes(x = 87.925, y = 6, xend = 87.925, yend = 6.3), color="black") +
geom_segment(aes(x = 87.925, y = 9.8, xend = 87.925, yend = 10.05), color="black") +

which results in: enter image description here

Upvotes: 0

smrt1119
smrt1119

Reputation: 282

You can use ggplot_build to pull out an interpolated value for each line . . . 

## create a fake ggplot to smooth your values using a linear fit ##
tmp.plot <- ggplot(stacked, aes(x = time, y = value, colour = variable)) + stat_smooth(method="lm")

## use ggplot_build to pull out the smoothing values ##
tmp.dat <- ggplot_build(tmp.plot)$data[[1]]

## find the x values closest to 87.925 for each variable ##
tmp.ids <- which(abs(tmp.dat$x - 87.925)<0.001)

## store the x and y values for each variable ##
new.points <- tmp.dat[tmp.ids,2:3]

## create a data frame with the new points ##
newpts <- data.frame(new.points,c("a","b"),c(8,8),c(16,16))

names(newpts) <- c("time","value","variable","PointSize","ShapeType")

## add the new points to your original data frame ##
stacked <- rbind(stacked,newpts)

## plot ##
MyPlot

Upvotes: 2

Related Questions