Is it possible to create a smooth, large geom_line() with varying colors in ggplot2?

user_13714197 0
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I was originally going to use a ribbon for this function, but ribbon was giving me an "Aesthetics can not vary within a ribbon" error. I tried a geom_smooth, geom_ribbon, and geom_line, and none of them worked for what I needed. The picture posted below is what I need, except that I would like those square joints between where the line changes colors to be either vertical and flush or round.

I looked at these posts already:

Shade Fill or Cover Area Density Under Curve

R ggplot Issue When Using Group Interaction

I've also tried using groups in a couple different ways. I should mention that I'm extremely new to ggplot2 and R in general, so any help or possible avenues would be appreciated. I've been using these resources, which you might find useful for this problem or for your own:

R For Data Science

GGPlot2: Elegant Graphics For Data Analysis

GGPlot2 Documentation

R Cookbook

Code:

library(ggplot2)

pdf("ggplot_learning.pdf")

data <- data.frame(
  xvals = c(0:5),
  yvals = c(4, 5, 4.5, 5.5, 5, 6),
  lower = c(3.9, 4.9, 4.4, 5.4, 4.9, 5.9),
  upper = c(4.1, 5.1, 4.6, 5.6, 5.1, 6.1)
)


plot <- ggplot(data, aes(xvals, yvals, ymax = 8, xmax = 8)) + 
  geom_line(aes(color = yvals, alpha = .3), lwd = 10) + 
  geom_line(aes(color = yvals)) + 
  theme(legend.position = "none")

print(plot)

What I have so far:

Graph With Rough Idea of What I Need

ggplot2 r
2 Answers

I'm not sure but maybe this:

data2 <- rbind(data, data[-1,]) 
data2 <- data2[order(data2$xvals),]
data2$n <- factor(head(rep(1:6, each=2),-1))

ggplot(data2, aes(xvals, yvals,color=n, fill=n, group=n)) + 
  geom_line() + 
  geom_ribbon(aes(ymin=lower, ymax=upper), alpha = 0.5)

enter image description here

Since you need groups for the geom_ribbon function, you need to specify each section. Thus, from 0 to 1, from 1 to 2 ... Therfore, I rbind the data twice, sort according to x and add a grouping factor n.

user_48706950

Here's something that looks a little better with geom_path, but it seems to ignore the linejoin = argument when the colors change:

ggplot(data, aes(x = xvals, y = yvals)) + 
  geom_path(aes(color = yvals, alpha = .3), lwd = 10,
            lineend="round",linejoin="miter") + 
  geom_line(aes(color = yvals)) + 
  theme(legend.position = "none")

enter image description here

user_130953260
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