R - colouring scatterplot points

Question

Hi there, I'm wondering why my code below makes the legend coloured, but the dots themselves are not:

# dataset <- data.frame(IDName, Value, Setpoints)
# dataset <- unique(dataset)

# Paste or type your script code here:
dat <- aggregate(Value ~ Setpoints + IDName, dataset, mean)

x <- dat$Value
y <- dat$Setpoints
z <- dataset$IDName

plot(x,y, main ="Turbidity Frequency Distribution",xlab="% Time < Turbidity level", ylab="Turbidity (NTU)")

lines(spline(x,y))

palette()
legend('topleft', legend = unique(z), col = 1:3, cex = 0.8, pch = 1)

#constant lines
abline(h=c(0.1,0.15,0.3), col=c("red","pink","purple"), lty=2, lwd=3)

Answer 1

Make sure that z is a factor . Then, use col = z when you create the plot. You will get colored points.

In your legend (the character values to appear in legend) to the levels of your factor z . In addition, set the colors based on unique(z) - they should match your points.

Here is the complete example. In the future, instead of putting data in a comment, please edit your question with the data. Also, you may want to consider ggplot2 for future plotting.

dat <- aggregate(Value ~ Setpoints + IDName, dataset, mean)

x <- dat$Value
y <- dat$Setpoints
z <- dataset$IDName

z <- factor(z)

plot(x, y, 
     main ="Turbidity Frequency Distribution",
     xlab="% Time < Turbidity level", 
     ylab="Turbidity (NTU)",
     col = z)

lines(spline(x,y))

palette()

legend('topleft', 
       legend = levels(z), 
       col = unique(z), 
       cex = 0.8, 
       pch = 1)

#constant lines
abline(h=c(0.1,0.15,0.3), col=c("red","pink","purple"), lty=2, lwd=3)

Plot

Data

dataset <- structure(list(IDName = c("Filter01", "Filter01", "Filter01", 
"Filter01", "Filter01", "Filter02", "Filter02", "Filter02", "Filter02", 
"Filter02"), Setpoints = c(0.16, 0.2, 0.3, 2, 2.2, 0.16, 0.2, 
0.3, 2, 2.2), Value = c(96.1, 96.2, 96.428, 99.603, 99.6, 98.8, 
98.9, 99.049, 99.194, 99.2)), class = "data.frame", row.names = c(NA, 
-10L))