As just discussed in the previous section, we saw how important the concept of layers was when creating a plot with ggplot2
. These layers are then combined with a coordinate system and other transformations which then generate the final plot. But what exactly are the layers? In the grammar of graphics as implemented in ggplot2
, the layers are responsible for the objects that we see in the graph. Each layer can come from a different dataset, have different geometry, and have a different aesthetic mapping. As you can see in Figure 3.1, the layers are composed of several components—the data
, aesthetic
, geom
, stat
, and position adjustment
. Not all these components are needed in order to create a layer, but a minimal layer can be created just by including the data, aesthetic mapping, and geom
that will define the type of plot to be generated. In fact, the geometry is a very important component of the layer since no visualization is possible without specifying the geometry.
ggplot2 Essentials
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ggplot2 Essentials
By:
Overview of this book
Table of Contents (14 chapters)
ggplot2 Essentials
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Free Chapter
Graphics in R
Getting Started
The Layers and Grammar of Graphics
Advanced Plotting Techniques
Controlling Plot Details
Special Applications of ggplot2
Index
Customer Reviews