How to Add Main Title and Manipulating Axis Labels in Ggplot2 in Rstudio

How to add main title and manipulating axis labels in ggplot2 in Rstudio

Try adding xlab and ggtitle:

p <- ggplot(data=dat, aes(x=FunctionClass, y=Frequency, fill=legend))+
geom_bar(stat="identity", position=position_dodge(), colour="seashell")
p + guides (fill = guide_legend(ncol = 1))+
xlab("Factor Class")+
ggtitle("Plant Growth")

adding x and y axis labels in ggplot2

[Note: edited to modernize ggplot syntax]

Your example is not reproducible since there is no ex1221new (there is an ex1221 in Sleuth2, so I guess that is what you meant). Also, you don't need (and shouldn't) pull columns out to send to ggplot. One advantage is that ggplot works with data.frames directly.

You can set the labels with xlab() and ylab(), or make it part of the scale_*.* call.

library("Sleuth2")
library("ggplot2")
ggplot(ex1221, aes(Discharge, Area)) +
  geom_point(aes(size=NO3)) + 
  scale_size_area() + 
  xlab("My x label") +
  ylab("My y label") +
  ggtitle("Weighted Scatterplot of Watershed Area vs. Discharge and Nitrogen Levels (PPM)")

ggplot(ex1221, aes(Discharge, Area)) +
  geom_point(aes(size=NO3)) + 
  scale_size_area("Nitrogen") + 
  scale_x_continuous("My x label") +
  scale_y_continuous("My y label") +
  ggtitle("Weighted Scatterplot of Watershed Area vs. Discharge and Nitrogen Levels (PPM)")

An alternate way to specify just labels (handy if you are not changing any other aspects of the scales) is using the labs function

ggplot(ex1221, aes(Discharge, Area)) +
  geom_point(aes(size=NO3)) + 
  scale_size_area() + 
  labs(size= "Nitrogen",
       x = "My x label",
       y = "My y label",
       title = "Weighted Scatterplot of Watershed Area vs. Discharge and Nitrogen Levels (PPM)")

which gives an identical figure to the one above.

How to create a common title in X and Y axis in an arrange of plots using `ggdraw` and `plot_grid()` in R?

I think you just need to play around with the margins before add_sub:

P <-plot_grid(
 p, p, leg, 
 p, p, leg,
 ncol = 3, rel_widths=c(2,2,1)
) + theme(plot.margin = margin(30, 30, -50, 50))

P <- add_sub(P, "x axis text", hjust = 1)
P <- add_sub(P, "y axis text", -0.05, 5, angle = 90)
ggdraw(P)

Center Plot title in ggplot2

From the release news of ggplot 2.2.0: "The main plot title is now left-aligned to better work better with a subtitle". See also the plot.title argument in ?theme: "left-aligned by default".

As pointed out by @J_F, you may add theme(plot.title = element_text(hjust = 0.5)) to center the title.

ggplot() +
  ggtitle("Default in 2.2.0 is left-aligned")

ggplot() +
  ggtitle("Use theme(plot.title = element_text(hjust = 0.5)) to center") +
  theme(plot.title = element_text(hjust = 0.5))

Rotating and spacing axis labels in ggplot2

Change the last line to

q + theme(axis.text.x = element_text(angle = 90, vjust = 0.5, hjust=1))

By default, the axes are aligned at the center of the text, even when rotated. When you rotate +/- 90 degrees, you usually want it to be aligned at the edge instead:

The image above is from this blog post.

Change size of axes title and labels in ggplot2

You can change axis text and label size with arguments axis.text= and axis.title= in function theme(). If you need, for example, change only x axis title size, then use axis.title.x=.

g+theme(axis.text=element_text(size=12),
        axis.title=element_text(size=14,face="bold"))

There is good examples about setting of different theme() parameters in ggplot2 page.

Putting x-axis at top of ggplot2 chart

You can move the x-axis labels to the top by adding

scale_x_discrete(position = "top") 

Change or modify x axis tick labels in R using ggplot2

create labels:

 SoilSciGuylabs <- c("Citrus", "Crop", "Cypress Swamp")

then add:

+ scale_x_discrete(labels= SoilSciGuylabs)

Put y axis title in top left corner of graph

Put it in the main plot title:

ggplot(data = xy) +
  geom_point(aes(x = x, y = y)) +
  ggtitle("very long label") +
  theme(plot.title = element_text(hjust = 0))

You can shove it slightly more to the left if you like using negative hjust values, although if you go too far the label will be clipped. In that case you might try playing with the plot.margin:

ggplot(data = xy) +
  geom_point(aes(x = x, y = y)) +
  ggtitle("very long label") +
  theme(plot.title = element_text(hjust = -0.3),
        plot.margin = rep(grid::unit(0.75,"in"),4))

So obviously this makes it difficult to add an actual title to the graph. You can always annotate manually using something like:

grid.text("Actual Title",y = unit(0.95,"npc"))

Or, vice-versa, use grid.text for the y label.

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