Scientific Visualization and Information Architecture

Transcription

1 Scientific Visualization and Information Architecture John P. Boyd University of Michigan Ann Arbor, Michigan jpboyd/ 2000 TO BE PUBLISHED 1

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3 Contents I Theory 1 1 How to Graph Badly or What NOT to Do Introduction Chartjunk Fonts Moiré Shading Pseudo 3-D Artificial Color Hype, I: Overinterpretation Hype, II: Graphical Carpet Bombing Wainer s Rules for Bad Graphs High Data Density Data-Hiding Data-Hiding by Graphing Disparate Quantities on the Same Scale Inconsistent Visual Metaphor Context-Free Data Area Instead of Length as a Visual Metaphor LabelWoes Emphasize the Unimportant Unnecessary Graphic Novelty The Gospel According to Tufte Data-Ink Show the Data Emphasize the Data Erase Non-Data-Ink or Down with the Grid! Erase Non-Data-Ink: Hurrah for Half-Framing! Erase Non-Data-Ink: Example of the Simplified Bar Graph Erase Redundant Data-Ink: Symmetry and Wrap-Around and All That Erasing: Eliminating the Graph Entirely Revise and Edit High Data Density The Shrink Principle Multifunctioning Graphical Elements Small Multiples or Animations-on-a-Page One Plus One Is Three Layering, Separation and Rubrication Word-Labels Are Better Than Letter-Labels Collapsing a Dimension or Escaping Flatland i

4 ii CONTENTS 2.9 Supplementary Material Small Multiples or Animations-on-a-Page Separation: Inset Graphs Wide is Wonderful: Aesthetics of Aspect Ratio Color or Why the Rainbow Isn t Golden Parallelism The Friendly Graphic II Scientific Graphs 93 3 Axis Magic Introduction Squeezing the Axis Log, Log-Log and All That Probability, Arctanh and Arcsinh Scales Monetary Inflation Nomography and Graphical Calculators Contour (Isoline) Plots Contour Plot The Central Problem of Contour Plots: Coding the Isolines Solid Positive-Valued/Dashed Negative-Valued Contour Plot Hachure Lines Filled Contour Plot Scalloping Choosing the Number of Contour Lines What to Contour: Variable Isoline-Spacing and Isolines of Logarithms Contouring in Irregular Regions Label Troubles Numerical Labels Jaggies or Piecewise Linear Plots of Contours Contouring Algorithms Contouring in Non-Rectangular Domains, II Summary Mesh Plots Scientific Visualization & Information Architecture Mesh Plot Mesh Plot with a Curtain or Skirt Mesh-Over-Contour Plot Waterfall Graph or Mesh-Lines-Parallel-To-One-Axis Only Truncated Mesh Plots Cutaway Mesh Plots Variable Grid Spacing to Code Positive and Negative Heights Compromise in Grid Density Importance of Viewpoint Spinning the Mesh Plot or Three-Dimensionality Through Animation Mesh Plots on Non-Rectangular Domains...158

5 CONTENTS iii 6 Arrow/Vector Plots Quiver/Arrow/Vector Plots/Porcupine Plot Vector Plots Superimposed on Other Graphs Vectors Derived from Scalars: Gradients and Hamiltonian-Field/Streamfunction Flow Area Quiver Plots Three-Dimensional Arrow/Vector/Quiver Plots III Graphical Arts Fonts and Typography Fonts Type Dimensions Monospaced and Proportional Type Font Sizes Serifs Fonts and Graphs FontsinLaTeX Drawing WhyDraw? Drawing in Matlab Introduction Importing Images Into Matlab Tracing an Image in Matlab Translating, Rescaling and Rotating Fractals: When the Algorithm is Mightier Than the Brush Texture Mapping Line Graphs on Surfaces Splines and Bezier Curves Drawing versus Painting or Bitmap versus Vector Drawing Programs: Tools Selecting Objects Views and Layers Zoom and Grab Pens and Brushes Stroke and Fill Patterns Joins, Intentional and Inadverdent Cutting Paths, Add/Delete Anchor Points & Converting Corner Points Text Tricks Shape Drawing Tools: Ellipses, Rectangles, Stars, Etc Transformation: Rotate, Reflect, Shear, Scale Filters, Styles and All That Rasterizing Objects or Photoshop-in-Illustrator Painting Tools Image-processing in Science Pictographs alias Visual Tables Scan-and-Decorate Drawing Theory and Drawing Programs...251

6 iv CONTENTS 8.24 Logos and Overheads: Cosmology According to Michael Turner Summary of Illustration Program Ideas Features That Are Useful in Scientific and Engineering Graphics Scanning Introduction Why-To or Reasons Scanning is Useful in Scientific Computing Recycling Graphs Scan and Modify Copyright and All That Copyright-Expired Images Scan, Trace and Delete the Original Asking Permission How-To Scanning Transparencies and Photographs IV Visualization as a Fine Art Visualization as Fine Art Introduction Gilbert: De Magnete(1600), Illustration of Experimental Method Cosmology Models of the Seventeenth Century Nodal Patterns of the Vibrations of a Thin Metal Plate Darwin s Flowers Hertzian s Discovery of Electromagnetic Waves Byerly (1893): Integrating Text and Graphics The Difference Between Two-Dimensional and One-Dimensional Waves The Importance of Color Schemes Repetition: Turbulence in the Sargasso Sea Philander (1990): Equatorial Currents Archetypes: Dürer s Rhino and the Recycling of Images Introduction: Aref s Rule Lineages Archetypes Graphical Lineages of the Renaissance Dürer s Rhino Hooke s Snowflakes The Isle of California Poincaré spear Equatorial Waves Horizontal Plane Vertical Cross-Section A Good Archetype A A Bestiary of Graph Species 301 A.1 Graph-As-Computer or Look-Up Table A.2 Graph-in-Table A.3 Hermaphrodite Graphs A.4 Filled Line Graph A.5 Pictograph/Visual Table Plot...307

7 CONTENTS v A.6 Silouette Chart (Variant of Line Chart) A.7 Solid Models A.8 Stem-and-Leaf Plots A.9 Tables and Other Non-Graphs A.9.1 Table-As-Graphic A.10 Timeline Graph A.11 Trajectory A.12 Tree Charts A.13 Trilinear Plot...319