Graph Creation

#data visualization

Stages

Three stages of making a graph:

  1. Specification
  2. Assembly
  3. Display

Specification

Statistical graphic specifications are expressed in six statements

  • DATA: a set of data operations that create variables from datasets
  • TRANS: variable transformations (e.g., rank)
  • SCALE: scale transformations (e.g., log)
  • COORD: a coordinate system (e.g., polar)
  • ELEMENT: graphs (e.g., points) and their aesthetic attributes (e.g., color)
  • GUIDE: one or more guides (axes, legends, etc.)

Assembly

Assembling a scene from a specification requires a variety of structures in order to index and link components with each other. One of the structures we can use is a network or a tree.

Display

Rendering the graphics. 

Syntax of the Grammar of Graphics

  • Create Variables: to extract data into variables
  • Apply Algebra: a graphics algebra consisting of three operators — cross, blend and nest — applied to a set of variables, together with a set of associated rules
  • Apply Scales: A categorical scale transformation associates the values of a categorical variable with the set of integers
  • Compute Statistics: do some statistics on the data
  • Construct Geometry: the grammar of graphics has a variety of different geometric graphing operations
  • Apply Coordinates: to make pie wedges, we apply a polar transformation to the shapes that were produced from the geometry
  • Compute Aesthetics: aesthetic functions translate a graph into a graphic

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Current Ref:

  • reading/grammar-of-graphics/graph-creation.md