更改R图中的颜色

Question

I am currently trying to plot some data and don't manage to obtain a nice result. I have a set of 51 individuals with each a specific value (Pn) and split within 14 groups. The closest thing I end up with is this kind of plot . I obtain it thanks to the simple code bellow, starting by ordering my values for the Individuals :

Individuals <- factor(Individuals,levels=Individuals[order(Pn)])
dotchart(Pn,label=Individuals,color=Groups)

The issue is that I only have 9 colors on this plot (so I lost information somehow) and I can't manage to find a way to apply manually one color per group.

I've also try to use the ggplot2 package by reading it could give nice looking things. In that case I can't manage to order properly the Individuals (the previous sorting doesn't seem to have any effect here), plus I end up with only different type of blue for the group representation which is not an efficient way to represent the information given by my data set. The plot I get is accessible here and I used the following code:

ggplot(data=gps)+geom_point(mapping=aes(x=Individuals, y=Pn, color=Groups))

I apologize if this question seems redundant but I couldn't figure a solution on my own, even following some answer given to others...

Thank you in advance!

EDIT: Using the RColorBrewer as suggested bellow sorted out the issue with the colors when I use the ggplot2 package.

Answer 1

I can't be sure without looking at your data, but it looks like Groups may be a numeric value. Try this:

gps$Groups <- as.factor(gps$Groups)

library(RColorBrewer)
ggplot(data=gps)+
geom_point(mapping=aes(x=Individuals, y=Pn, color=Groups))+ 
scale_colour_brewer(palette = "Set1")

Answer 2

I believe you are looking for the scale_color_manual() function within ggplot2 . You didn't provide a reproducible example, but try something along the lines of this:

ggplot(data=gps, mapping=aes(x=Individuals, y=Pn, color=Groups))+
    geom_point() +
    scale_color_manual(values = c('GROUP1' = 'color_value_1',
                                  'GROUP2' = 'color_value_2',
                                  'GROUP3' = 'color_value_3'))

Replace GROUPX with the values inside your Group column, and replace color_value_x with whatever colors you want to use.

A good resource for further learning about ggplot2 is chapter 3 of R For Data Science , which you can read here: http://r4ds.had.co.nz/data-visualisation.html