Here are [some](http://xkcd.com/55/) [other](http://xkcd.com/287/) [math](http://xkcd.com/435/)/[stats](http://xkcd.com/539/) [related](http://xkcd.com/410/) xkcd comics.
I just received a copy of [IDL Primer](http://www.amazon.com/gp/redirect.html%3FASIN=0967127033%26tag=harmonicfunct-20%26lcode=xm2%26cID=2025%26ccmID=165953%26location=/o/ASIN/0967127033%253FSubscriptionId=0PZ7TM66EXQCXFVTMTR2) by Ronn Kling. (*Full disclousre: I received a free copy because Ronn used my [Periodic Table of IDL Operators](http://michaelgalloy.com/2006/11/01/periodic-table-of-idl-operators.html) on the back cover.*) It’s a pocket sized “quick reference” that provides a quick introduction to the main functional areas of IDL: the IDL Environment (DE is covered, get Kling’s [Navigating the Workbench](http://www.amazon.com/gp/redirect.html%3FASIN=0967127041%26tag=harmonicfunct-20%26lcode=xm2%26cID=2025%26ccmID=165953%26location=/o/ASIN/0967127041%253FSubscriptionId=0PZ7TM66EXQCXFVTMTR2) for coverage of the Workbench), syntax, array operations, program flow, 2D and 3D graphics, image processing, object graphics, file I/O, mapping, and animation. I have found it to be a quite handy reference, particularly the list of “Important Routines by Function” at the back (similar to the [Functional List of IDL Routines](http://idlastro.gsfc.nasa.gov/idl_html_help/Functional_List_of_IDL_Routines.html) in the online help).
I finally got a copy of [*Information Visualization*](http://www.amazon.com/gp/redirect.html?ie=UTF8&location=http%3A%2F%2Fwww.amazon.com%2FInformation-Visualization-Second-Interactive-Technologies%2Fdp%2F1558608192%3Fie%3DUTF8%26s%3Dbooks%26qid%3D1200690726%26sr%3D8-1&tag=harmonicfunct-20&linkCode=ur2&camp=1789&creative=9325) by Colin Ware and started reading it. *Information Visualization* and [*Readings in Information Visualization*](http://www.amazon.com/gp/redirect.html?ie=UTF8&location=http%3A%2F%2Fwww.amazon.com%2FReadings-Information-Visualization-Interactive-Technologies%2Fdp%2F1558605339%3Fie%3DUTF8%26s%3Dbooks%26qid%3D1200690885%26sr%3D8-1&tag=harmonicfunct-20&linkCode=ur2&camp=1789&creative=9325) edited by Stuart Card, Jock Mackinlay, and Ben Schneiderman are considered the classics in the field of Information Visualization (or InfoVis).
In *Information Visualization*, Ware evaluates visualizations using the scientific methods of psychology. Perception, vision, color, etc. are discussed and used to reach conclusions for creating visualizations.
The section on various flow visualization techniques was very useful since I’ve been [thinking](http://michaelgalloy.com/2007/11/16/lic-flow-visualization.html) about [line-integral convolutions (LIC)](http://michaelgalloy.com/2007/12/09/lic-flow-code.html) lately. There were also discussions of choosing colors, using texture maps, 3D shading, and a few plot types that have changed the way I will do some types of visualizations in the future.
In summary, I would say this is a useful book if you are serious about improving your visualizations. (Colin Ware has a [new book](http://www.amazon.com/gp/redirect.html?ie=UTF8&location=http%3A%2F%2Fwww.amazon.com%2FVisual-Thinking-Design-Colin-Ware%2Fdp%2F0123708966%3Fie%3DUTF8%26s%3Dbooks%26qid%3D1200792953%26sr%3D8-2&tag=harmonicfunct-20&linkCode=ur2&camp=1789&creative=9325) coming out this April that looks interesting as well.)
I went to a talk titled “Effective Flow Visualization” by [Colin Ware](http://marine.unh.edu/facWare.htm) at NOAA last Friday. Dr. Ware works on issues of scientific visualization from an angle that was new to me: he studies human perception of visualizations. An interesting aspect of this study is that he tries to objectively measure the effectiveness of a given visualization. To do these tests he has people try to do common tasks with a visualization, like predict a dropped particle’s path in a flow visualization, and compares their answers to the computed answer. I haven’t read his book [*Information Visualization: Perception for Design*](http://www.amazon.com/gp/product/1558608192?ie=UTF8&tag=harmonicfunct-20&linkCode=as2&camp=1789&creative=9325&creativeASIN=1558608192), but his talk has motivated me to read it.
Dr. Ware is the Director of the [Data Visualization Research Lab](http://www.ccom.unh.edu/vislab/CWBio.html) part of the Center for Coastal and Ocean Mapping at the University of New Hampshire.
The largest of the four books in this series by Edward Tufte, [*Beautiful Evidence*](http://www.amazon.com/exec/obidos/redirect?link_code=as2&path=ASIN/0961392177&tag=harmonicfunct-20&camp=1789&creative=9325) is a welcome addition. It includes excellent examples of graphical excellence, in equally excellent production, which lead to general principles of presentation of data. I encourage you to take Tufte’s own advice about consuming evidence presentations; skip this second hand discussion of his book (i.e. the rest of this post) and go straight to the primary resource, *Beautiful Evidence* itself.
My favorite aspect of Tufte’s books are the examples: both good and bad. The good for examples to emulate; the bad for the humor.*Beautiful Evidence* is no exception, there are hundreds of images, graphs, diagrams, tables, and arrows in this book. The most notable bad examples come from the chapter on PowerPoint presentations (available as a [separate pamphlet](http://www.amazon.com/exec/obidos/redirect?link_code=as2&path=ASIN/0961392169&tag=harmonicfunct-20&camp=1789&creative=9325)). The most notable good example is the extended discussion of Minard’s data-map of the French invasion of Russia, a Tufte favorite. Even the good examples are often dissected to find weaknesses.
There aren’t many third party IDL books: David Fanning has one, Liam Gumley has one, and Ronn Kling has three. Now [Ken Bowman](http://www.met.tamu.edu/people/faculty/bowman.php), a professor at Texas A&M University in the Department of Atmospheric Sciences, enters the fray with *An Introduction to Programming with IDL*. This book is geared towards a new user of IDL without programming experience. It covers the necessary topics to get started in IDL basic variable concepts, analysis, file input/output, and direct graphics visualizations including many exercises for these topics. It makes it a good fit for the academics market. From the Preface:
> This book is intended to be used in an introductory computer
> programming course for science and engineering students at
> either the undergraduate or graduate level.
I think it achieves this goal very well, but don’t look here if you want to take your programming beyond basic analysis and visualization.
A major strength of the book are the downloadable example programs with their documentation, data files, and output. To try the examples, make sure to run `@startup` first to setup your IDL session.
See the [book’s website](http://idl.tamu.edu/) for more information including table of contents, errata, downloadable example programs, and even the Interpolation chapter.
Edward Tufte’s latest book, *Beautiful Evidence* can be pre-ordered from [Amazon.com](http://www.amazon.com/exec/obidos/redirect?link_code=as2&path=ASIN/0961392177&tag=harmonicfunct-20&camp=1789&creative=9325) or directly from [Tufte’s site](http://www.edwardtufte.com/tufte/books_be). Not sure if it means anything, but Amazon says it will be available July 30 and Tufte’s site says May. Mine is on order from his website; I will be sure to post my thoughts once I get my hands on it.
The topics covered in the book have been discussion in the [forums](http://www.edwardtufte.com/bboard/q-and-a?topic_id=1) on Tufte’s [website](http://www.edwardtufte.com/tufte/) for the past few years. The Powerpoint chapter has also been available as a pamphlet for a few years. They are:
1. Mapped Pictures: Images as Evidence and Explanation
2. Sparklines: Intense, Simple, Word-Sized Graphics
3. Links and Casual Arrows: Ambiguity in Action
4. The Fundamental Principles of Analytical Design
5. Corruption in Evidence Presentations: A Consumer’s Guide to Effects Without Causes, Cherry Picking, Overreaching, Chartjunk, and the Rage to Conclude
6. The Cognitive Style of Powerpoint: Pitching Out Corrupts Within
7. Sculpture Pedestals: Meaning, Practice, Depedestalization
8. Language Sculptures
Tufte’s previous books include [*The Visual Display of Quantitative Information*](http://www.amazon.com/exec/obidos/redirect?link_code=as2&path=ASIN/096139210X&tag=harmonicfunct-20&camp=1789&creative=9325), [*Visual Explanations: Images and Quantities, Evidence and Narrative*](http://www.amazon.com/exec/obidos/redirect?link_code=as2&path=ASIN/0961392126&tag=harmonicfunct-20&camp=1789&creative=9325) and [*Envisioning Information*](http://www.amazon.com/exec/obidos/redirect?link_code=as2&path=ASIN/0961392118&tag=harmonicfunct-20&camp=1789&creative=9325). Every one has been a gem worth the 7-9 years that he has put into creating each one.