ggplot2 stacked barplot size & color

Question

These are probably some easy questions, but I 'm learning. I'm using ggplot2 for stacked barplots and I figured out how to do that in a basic form:

df<- data
stack <-ggplot(df,aes(x=group, y=average.contribution, fill=taxa)) + 
          geom_bar(stat="identity")

(dataset with bacterial abundance)

but I have problems to adjust the size of the plot, I couldn't find good examples (probably with theme() ).

In particular:

1. define the size of the plot (eg 5cm x 5 cm)
2. define the width of the bars
3. distance of the axis label to the axis
4. font used in the plot
5. define the size of the legend

And are there color vectors of various themes out there I could use instead from scale_fill_brewer() ? I need more than 7 colors.

Answer 1

I found some solutions to make plot more attractive and to adjust the size by myself:

df<-so2
stack<-ggplot(df,aes(x= group, y=average.contribution, fill=taxa)) 
+ geom_bar(stat="identity", width=.7) 
+ facet_grid(. ~ fac) +scale_y_continuous(limits=c(0,100)) 
+ theme(panel.grid.minor.x=element_blank(), panel.grid.major.x=element_blank()) 
+ theme_bw() 

ggsave(stack, file="stack.pdf", width=10, height=10)

thus remains mostly the question about the color vectors

Answer 2

When you want to have more than 7 colors, you have several options:

# your plot code as a starting point
stck <- ggplot(df,aes(x= group, y=average.contribution, fill=taxa)) + 
  geom_bar(stat="identity", width=.7) + 
  facet_grid(. ~ fac) + 
  scale_y_continuous(limits=c(0,100)) + 
  theme(panel.grid.minor.x=element_blank(), panel.grid.major.x=element_blank()) + 
  theme_bw()

You can choose to set the colors maually:

# manually with color names
stck + scale_colour_manual(values=c("red", "blue")) # 2 colors as example, add as many as you need

# manually with RGB values
stck + scale_colour_manual(values=c("#CC6666", "#7777DD"))

You can also use the RColorBrewer package:

library(RColorBrewer)
display.brewer.all() # shows the different palettes you can choose from

stck + scale_fill_brewer(palette="Set3") # a color palette with 12 colors

---

For changing the distance of the axis label to the axis, you have at least two options:

# inserting blank lines with \n
stck + xlab("\nLabel")

# vertically or horizontally adjusting the label
stck + theme(axis.text.x = element_text(hjust=-1, vjust=-1)) # ylab -> hjust; xlab -> vjust

---

For changing the appearance of the text:

element_text(size=14, face="bold", color="red", family = "sans")

When you want to use a specific font, installing the extrafont package is a possibility. See this answer