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Researchers have created a next-generation zoom function
to view and compare portions of complex graphics such as city maps, scientific
images, or pages of text.
The new tool, PolyZoom, makes it possible to
simultaneously magnify many parts of a graphic without losing sight of the
original picture.
“With standard programs, once you zoom in you lose
perspective and have to zoom out again so see that bigger picture,” said Niklas
Elmqvist, an assistant professor of electrical and computer engineering.
“This new tool maintains your perspective or orientation.”
The zoomed-in regions appear as separate pullout boxes
displayed next to each other. These boxes, or “correlated graphics,”
allow the user to see where the magnified viewpoints are located in relation to
each other and the whole.
“The tool is useful if you are trying to compare
different spaces on a map, like the city centers of two major metropolitan areas,
segments of a Hubble Space Telescope picture or even pages in a lengthy
document,” said Elmqvist, who is working with doctoral students Waqas
Javed and Sohaib Ghani. “Say you are a historian looking at a large
collection of scanned pages from a book. You might want to zoom into a
particular page and read the words, or look at many pages at the same time and
compare those.
The researchers tested PolyZoom in two user studies,
comparing it with standard navigation techniques.
“We wanted to make sure that using PolyZoom doesn’t
slow people down and that it is as fast as or faster than navigating with a
normal Web browser,” Elmqvist said. “In both user studies we found
that people were faster using our technique compared to existing products. It
provides new ways of viewing several parts of a map at once, for example, which
you currently can’t do with existing products.”
Findings will be detailed in a paper being presented
during the Association for Computing Machinery’s CHI 2012 conference.
The tool is designed for users navigating “multiscale
visual space.”
“The fact that you can keep zooming in, continually
showing more and more detail, is what we call multiscale visual space,”
Elmqvist said. “The most common techniques for navigating in multiscale
visual spaces are pan, zoom, and bird’s eye views. However, these techniques
are often tedious and cumbersome to use, especially when objects of interest
are located far apart.”
The tool allows segments to be color-coded for ease of
comparison.
The researchers built a demo that works in conjunction
with Google Maps.
“Our implementation is standalone, but the
demonstration can be run in any Web browser,” Elmqvist said.
“However, it is certainly possible to incorporate this into an existing
program such as Google Maps, GIS, and GPS software.”
