The End of Zero-Hit Queries: Query Previews for NASA's Global Change
Master Directory
The End of Zero-Hit Queries: Query Previews for NASA's Global Change
Master Directory
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Date
1998-10-15
Authors
Greene, Stephan
Tanin, Egemen
Plaisant, Catherine
Shneiderman, Ben
Olsen, Lola
Major, Gene
Johns, Steve
Advisor
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DRUM DOI
Abstract
The Human-Computer Interaction Laboratory (HCIL) of the University of
Maryland and NASA have collaborated over the last three years to refine
and apply user interface research concepts developed at HCIL in order to
improve the usability of NASA data services. The research focused on
dynamic query user interfaces, visualization, and overview +preview
designs. An operational prototype, using query previews, was implemented
with NASA's Global Change Master Directory (GCMD), a directory service for
earth science data sets. Users can see the histogram of the data
distribution over several attributes and choose among attribute values. A
result bar shows the cardinality of the result set, thereby preventing
users from submitting queries that would have zero hits. Our experience
confirmed the importance of metadata accuracy and completeness. The query
preview interfaces make visible problems or holes in the metadata that are
unnoticeable with classic form fill-in interfaces. This could be seen as a
problem, but we think that it will have a long-term beneficial effect on
the quality of the metadata as data providers will be compelled to produce
more complete and accurate metadata. The adaptation of the research
prototype to the NASA data required revised data structures and
algorithms.
(Also cross-referenced as UMIACS-TR-97-84)