add more info about plot title customization

_episodes_rmd/04-ggplot2.Rmd

@@ -315,9 +315,9 @@ Now we can use this new data frame to create our plot showing the
 percentage of each house type in each village.
 
 ```{r barplot-wall-type}
-ggplot(percent_wall_type, aes(x = village, y = percent, fill = respondent_wall_type)) +
-    geom_bar(stat = "identity", position = "dodge")
-```
+ ggplot(percent_wall_type, aes(x = village, y = percent, fill = respondent_wall_type)) +
+     geom_bar(stat = "identity", position = "dodge")
+ ```
 
 > ## Exercise
 >
@@ -499,13 +499,14 @@ After our manipulations, you may notice that the values on the x-axis are still
 not properly readable. Let's change the orientation of the labels and adjust
 them vertically and horizontally so they don't overlap. You can use a 90-degree
 angle, or experiment to find the appropriate angle for diagonally oriented
-labels:
+labels. With a larger font, the title also runs off. We can "\n" in the string
+for the title to insert a new line:
 
 ```{r ggplot-customization-label-orientation, purl=FALSE}
 ggplot(percent_items, aes(x = village, y = percent)) +
     geom_bar(stat = "identity", position = "dodge") +
-    labs(title = "Percent of respondents in each village who owned each item",
     facet_wrap(~ items) +
+    labs(title = "Percent of respondents in each village \n who owned each item",
          x = "Village",
          y = "Percent of Respondents") +
     theme_bw() +
@@ -515,19 +516,21 @@ ggplot(percent_items, aes(x = village, y = percent)) +
 ```
 
 If you like the changes you created better than the default theme, you can save
-them as an object to be able to easily apply them to other plots you may create:
+them as an object to be able to easily apply them to other plots you may create.
+We can also add `plot.title = element_text(hjust = 0.5)` to center the title:
 
 
 ```{r ggplot-custom-themes, purl=FALSE}
 grey_theme <- theme(axis.text.x = element_text(colour = "grey20", size = 12, angle = 45, hjust = 0.5, vjust = 0.5),
                     axis.text.y = element_text(colour = "grey20", size = 12),
-                    text = element_text(size = 16))
+                    text = element_text(size = 16),
+                    plot.title = element_text(hjust = 0.5))
 
 
 ggplot(percent_items, aes(x = village, y = percent)) +
     geom_bar(stat = "identity", position = "dodge") +
-    labs(title = "Percent of respondents in each village who owned each item",
     facet_wrap(~ items) +
+    labs(title = "Percent of respondents in each village \n who owned each item",
          x = "Village",
          y = "Percent of Respondents") +
     grey_theme
@@ -554,14 +557,15 @@ Make sure you have the `fig_output/` folder in your working directory.
 ```{r ggsave-example, eval=FALSE, purl=FALSE}
 my_plot <- ggplot(percent_items, aes(x = village, y = percent)) +
     geom_bar(stat = "identity", position = "dodge") +
-    labs(title = "Percent of respondents in each village who owned each item",
     facet_wrap(~ items) +
+    labs(title = "Percent of respondents in each village \n who owned each item",
          x = "Village",
          y = "Percent of Respondents") +
     theme_bw() +
     theme(axis.text.x = element_text(colour = "grey20", size = 12, angle = 45, hjust = 0.5, vjust = 0.5),
           axis.text.y = element_text(colour = "grey20", size = 12),
-          text = element_text(size = 16))
+          text = element_text(size = 16),
+          plot.title = element_text(hjust = 0.5))
 
 ggsave("fig_output/name_of_file.png", my_plot, width = 15, height = 10)
 ```