Archive for January 2007


Intro to Computer Graphics courses

January 27th, 2007 — 2:56pm

Pete Shirley has invited people to follow along with the assignments in his Intro to Graphics course covering the Reyes architecture.

Pat Hanrahan’s new intro course is covering an eclectic mix of topics. You can also check out his interesting use of a course Wiki.

At UNC, another former BYU student, Brandon Lloyd, is teaching a more typical intro course covering rasterization and raytracing.

And back at BYU, Robert Burton’s intro course is asking students to reimplement the OpenGL pipeline.

Comment » | Uncategorized

TreeMaps

January 25th, 2007 — 1:30am

I’ve been meaning to get back to TreeMaps for awhile. The recently unveiled Many-Eyes includes a TreeMap visualization. Martin Wattenberg (who did some research on TreeMap layouts) provides a typical example:



My main complaint with TreeMaps is their ugliness. Every TreeMap I have seen, including this one, look disorganized. Basically, we can only see the top level of the hierarchy, indicated with the strong dark lines and labeled. All other levels disappear into the patchwork mess. So one of the “strengths” of TreeMaps, the ability to directly view the hierarchy, is effectively neutered.

The layout also ignores good graphic design. Elements are not aligned and they do not visually cluster in meaningful ways. This is in contrast to indented lists, another common way to show hierarchical data, which use alignment and clustering very effectively to communicate the organization of the hierarchy.

More effective use of whitespace could dramatically improve the appearance of TreeMaps, but so few people use it well. Here‘s an example that does. Also notice how the alignment makes the diagram look very organized.

Next time: the travesty of Cushion TreeMaps.

1 comment » | visualization

Workshop Report

January 25th, 2007 — 12:50am

A couple weeks ago I attended a small Visualization workshop organized by the DHS and the CIA in New Mexico. It was my first time to the state. I met a number of interesting people in the Visualization community, including David Salesin, from Adobe, and Stephen Few.

The discussion focused on how documents and presentations could be produced more effectively and efficiently. Two main issues were raised:

  1. Best practices need to be codified.
    • There is a lot of research on how to communicate spread across a large number of fields including education, rhetoric, HCI, visualization, cognition, etc.
    • Having this knowledge consolidated and organized would be helpful for people.
    • With this knowledge, programs could be developed to automatically apply (or suggest) best practices, reducing the time needed to create an effective document.
  2. Documents need more background.
    • The analysis process behind a document is often as important as the document itself (containing just the final conclusions). If we had a way to track the analysis, it would be possible for document readers to drill-down into questionable conclusions. It would also be possible to check the analysis for consistency with changing conditions. For example if the document relied a piece of intelligence that was later shown to be false, the entire document could be flagged (automatically?) as “Overtaken by Events”.

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Critiquing Treemaps

January 5th, 2007 — 11:52am

TreeMaps are a popular hierarchical visualization technique developed by Ben Shneiderman. Despite the emphasis they have received in visualization literature over the last decade, TreeMaps remain a very limited tool. In the next few days, I want to explore why this is true.

Comment » | visualization

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