| Icons to represent sets with highly variable sizes can come from an icon family based on powers. |
At Virginia Tech, in conjunction with the Envision Project, we are building a large object-oriented database of computer science literature, with a graphical front end. One of our concerns is visually representing sets of retrieved documents. They can vary greatly in size; a query for “computers” might find 100,000 documents, but a search for “logarithmicon” might only find one.
We are considering using icons to represent these sets, with features of the icon suggesting the number of documents. We are creating icon families [Marcus 84], letting area covered by the icon suggest the size of the set.
Logarithmicons
The key to these icon designs is the mapping of the logarithm of set size to an icon’s attribute. This is because:
- there is great variability in cluster size,
- most clusters are somewhat small,
- a linear mapping would make it difficult to distinguish small from medium-sized clusters.
The icon designs (in Figure 1) represent clusters of various sizes. Icons share these features:
- They have a border (in one case a circle, in the other a triangle) that provides an indication of maximum icon size.
- They map the logarithm of set size to a linear feature, and use it to increase the area covered. A linear increase in radius or height increases area covered quadratically, which hints at the exponential increase involved.
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| Figure 1. Two families of logarithmicons. |
The “rungs” in the second (triangle-based) family show discrete steps, for a clear visual depiction of the various orders of magnitude. It might be better if there were an indication of the number of steps available, but there is only so much we can show in a 32×32 pixel icon.
In summary, the abstract icons presented here suggest a mapping that lets an icon feature represent widely varying sizes.
Postscript: The name “logarithmicon” is derived from merging the words “logarithmic” and “icon”. A quick skim through the dictionary suggests other possibilities: algorithmicons (to do the work), bombasticons (for multimedia demos), iambicons (for Shakespeare), and telepathicons (the ultimate goal).
References
[Marcus 84] Aaron Marcus. “Corporate Identity for Iconic Interface Design: The Graphic Design Perspective,” IEEE Computer Graphics and Applications, pp. 24-32, December, 1984.
Acknowledgements
I would like to acknowledge discussions with the Envision Project team, particularly Dr. Ed Fox. This work was done in 1992 while I was a grad student at Virginia Tech. I was partially supported by NSF grant 4-27343.
[Written Dec., 1992; published on xp123.com July, 1998.]