January The Visual Display of Quantitative Information Alyssa A. Goodman Professor of Astronomy

January Visual Displays of Quantitative Information Maps Tables Graphs Charts Illustrations & Combinations Thereof

January “Core” Principles for the Best Visual Displays (of Quantitative) Information 1.Clarity 2.Tailor to Audience 3.Optimize Display Design 4.Maximum Information, Minimum Mess 5.Consider Delivery Method (hardcopy, blackboard, web, PPT, movie vs. still)

January Questions to Always Ask What’s this “VDQI” for? –Data exploration –Hypothesis testing –Making a point –Illustrating/demonstrating an idea –Condensing information –>1 of the above (best answer) Does my display pass the “interocular impact test”?

January Data Exploration

January Hypothesis (or “Model”) Testing

January Making a Point Days “predictor” dog had a cold are marked in pink

January Illustration Area = (a x b)/2 Perimeter=a+b+c a b c c=(a 2 + b 2 ) 1/2

January Illustration

January Condensing Information

January Questions to Always Ask What’s this “VDQI” for? –Data exploration –Hypothesis testing –Making a point –Illustrating/demonstrating an idea –Condensing information –>1 of the above (best answer) Does my display pass the “interocular impact test”?

January nd Half Tables More Sample Graphics Critiques PowerPoint

January Tables

January Tables

January Tables When is a table better than a graph or chart? How many independent quantities are listed in a table? –Are any of the entries “correlated”? Should they be? Is the numerical accuracy shown appropriate (# of “significant figures”)?

January More Sample Graphics

January “ Small Multiples” Galileo’s Moon

Data Exploration Leonardo da Vinci

January Data Exploration

January Data Exploration

January Questions Raised by the Movie Is the Earth in danger? –Resolution and its deception potential –What is the uncertainty in the positions? –What is the time scale? Which one is Earth in the movie? –The importance of labeling (What is the coordinate system? –How is the Solar System “viewed” from above?)

Hypothesis Testing John Snow & the London Cholera Epidemic 1854 Reproduced from Visual and Statistical Thinking, ©E.R. Tufte 1997, based on Snow’s drawing.

January Critiques

January

Goodman, Barranco, Wilner & Heyer 1998

January PowerPoint for Good & Evil Good Forces good handwriting Animation/overlays Clear record of presentations Color Good graphics import Easy reorganization Evil Gratuitous Graphics--too much glitz, no substance Bulleted list after bulleted list Poor graphics import (e.g. EPS) Random access Difficult Spinning things

Intensity "Velocity" Observed Spectrum Telescope  Spectrometer All thanks to Doppler Velocity from Spectroscopy

Radio Spectral-line Observations of Interstellar Clouds

January Episodic Outflows: Steep Mass-Velocity Slopes Result from Summed Bursts Power-law Slope of Sum = -2.7 (arbitrarily >2) Slope of Each Outburst = -2 as in Matzner & McKee 2000 Arce & Goodman 2001b

January COMPLETE Preview: Discovery of a Heated Dust Ring in Ophiuchus Goodman, Li & Schnee pc

January …and the famous “1RXS J ” is right in the Middle !? 2 pc

Star Formation >>101 Bate, Bonnell & Bromm 2002 MHD turbulence gives “t=0” conditions; Jeans mass=1 M sun 50 M sun, 0.38 pc, n avg =3 x 10 5 ptcls/cc forms ~50 objects T=10 K SPH, no B or  movie=1.4 free-fall times

January “Core” Principals for the Best Visual Displays (of Quantitative) Information 1.Clarity 2.Tailor to Audience 3.Optimize Display Design 4.Maximum Information, Minimum Mess 5.Consider Delivery Method (hardcopy, blackboard, web, PPT, movie vs. still)

January So Many Graphs, So Little Time Graphs show relationships amongst more than one variable (“multivariate”) “Time” can be, but is not always, a relevant variable Most graphs are drawn in two dimensions A map can be considered as a very direct form of graph