Archive for December 2006


If only everyone did this…

December 18th, 2006 — 10:05pm

Today I came across the website of Marcia K. Johnson, a professor of Psychology at Yale. She links to PDFs of every single one of her publications all the way back to 1972. That’s impressive.

I was looking for her paper “Contextual prerequisites for understanding: Some investigations of comprehension and recall”, and was very surprised to find it online. Typically, anything written before about 1990 can be very hard to find online (unless it’s in the ACM Digital Library).

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Animation

December 16th, 2006 — 3:54am

Today I read Animation: can it facilitate? by Tversky, Morrison, and Betrancourt. They argue that animation has little power to “facilitate comprehension, learning, memory, communication and inference” since it violates the Apprehension Principle.

I think they’re right. Comprehension requires time to analyze the graphic and to develop a mental model. An animated graphic is continually presenting new information; interrupting our attempts to understand.

When I’ve used animations or movies in my own learning, I find myself having to compensate by repeating it multiple times or pausing at key frames, etc. In essence, I’m trying to build a static understanding of the animation.

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Desiderata

December 15th, 2006 — 12:45am

Do we really need this word?

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SpaceBalls

December 15th, 2006 — 12:37am

My brother pointed me to this updated SpaceBall product. There was always an old SpaceBall lying around in the lab at BYU. It had some mysterious connector that wouldn’t work with any of the machines in the lab, so it never got used. Are these at all useful for 3D work? It seems like Maya’s interface is pretty simple. Mouse plus Ctrl, Alt, or Shift to choose pan, rotate, or zoom (not necessarily in that order). Does anyone have experience using a SpaceBall?

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Google Maps vs. Microsoft Live Maps

December 14th, 2006 — 7:32pm

Placing labels on maps is a hard problem. Although quite a bit of work has been done on how to place labels so that they don’t overlap, not much work has been done on how to place labels in an aesthetically pleasing manner. In an effort to understand what’s in production already I decided to make a brief comparison of Google Maps and Microsoft’s Live Maps.

The two maps compared are for the Redmond, Washington area where I lived for the past year. You can compare them yourself by opening Google’s and Microsoft’s versions of the same area. I was looking at them on a relatively large monitor, so you may need to scroll around a little bit to see the same things.

  1. Initial Impressions. Microsoft uses a subdued color scheme which reminds me of Eduard Imhof’s maps. The parks could be slightly greener, but otherwise it’s very nice. Google’s color scheme is more saturated and, to my eye, not as clean. On the other hand, Microsoft’s map is noticeably blurry, apparently caused by too much anti-aliasing. The small, unlabeled roads in Google are too strong, they distract from the rest of the map. The unlabeled roads in Microsoft are lighter which looks better. However, some of their labeled roads are also very light! It’s often unclear with which street the label is associated. As a general rule: if the street is labeled it should be dark, if not, it should be very light or not rendered at all.
  2. Label Selection. One of the most noticeable differences is the types of labels shown at this zoom level. Microsoft labels a lot of streets, but only one park out of dozens. Google’s map labels almost all the parks and only labels the largest streets. Park names are useful as landmarks, but it they can’t be nearly as useful as street names. Why waste screen space on them?
  3. Label Clutter. Since Microsoft shows so many street labels, it can suffer from unsightly cluttering, although labels never actually overlap. Notice how the meeting of “NE 85th St” and “116th Ave NE” at right angles looks awkward. Also the coincidence of the top of the ‘E’ in “124th Ave NE” with the edge of the freeway is distracting. Also notice the lack of any alignment and the seeming arbitrary top-to-bottom vs. bottom-to-top reading of the vertical text.
  4. Label Layout. Microsoft seems inconsistent in placing street labels adjacent to or directly over the road. Google always places the text over the street.
  5. Text Layout. In both maps, the street label text follows the path of the street. This leads to some very strange text, especially on Microsoft’s map. “Sammamish” is really one word. An obvious solution would be to smooth the path so this doesn’t happen. The rotation and baseline of a label’s text should change smoothly over the label. A related problem is that of character spacing. Notice that the ‘i’ has almost disappeared from the word “Sammamish”.
  6. Label Contrast. Both maps render a background behind the text to make the label stand out from the map. Google’s is a nearly opaque white border (or yellow, for main roads). Microsoft uses a much more subtle mask. Visually, I prefer Microsoft’s approach. However, I did notice that in many places Microsoft’s mask would obscure the road, making the label appear unassociated with anything on the map. Google neatly avoids this problem by making the text border the same color as the road (yellow), this provides more visual continuity to the road even when obscured by the label.
  7. Labeling Areas. Labeling of areas doesn’t work very well as you zoom into the area. For example, city labels remain even after you have zoomed so that the city fills up almost the entire screen. It appears that the city label is identifying a specific intersection, rather than an entire area. I’d be interested to see how traditional maps deal with this problem.

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Obvious sentence of the day

December 14th, 2006 — 6:34pm

Not graphics related at all, but I laughed when I read this (USAToday):

If a Republican replaced any Democrat in the Senate, a 50-50 tie would be broken by Vice President Dick Cheney, giving Republicans the slimmest of majorities. Such a majority wouldn’t only be critical in party-line votes, but also in selecting committee chairmanships and controlling Senate procedures.

The last 50-50 Senate also involved a South Dakotan, former Sen. Tom Daschle, who was head of the Senate Democrats at the time.

South Dakota became a state in…1889. I’d say that the chances that the last 50-50 Senate included a South Dakotan are pretty high.

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Genesis

December 14th, 2006 — 4:15am

I’d been thinking about creating a computer graphics blog for awhile. When I saw that Pete Shirley had recently started one, I figured it was the time to jump on the bandwagon.

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