Exploratory Access to Geographic Libraries
Vincent Schenkelaars and Max Egenhofer
Abstract
Users of digital geographic libraries face the challenge of
discovering the dataset they are interested in. When locating and
selecting spatial datasets, different scenarios may occur with
varying levels of knowledge about the datasets desired. For
example, some users may have precise information about what they
want ("I need the most recent Spot image covering Orono, Maine"),
while others may be more vague in their descriptions ("To test my
hydrological runoff model, I need a dataset that includes the
terrain with steep slopes as well as some flat areas with sandy
clay"). Usually, the collection of datasets available is by far too
large to be examined one-by-one. The sheer size of geographic
libraries poses a performance problem for the digital library--how
to retrieve enough data within a short time so that users can make
decisions--as well as a cognitive overload for the users--how to
select from among all datasets available those datasets that are
worth a more detailed examination. We propose an interactive
geographic browser with which users can explore a geographic
library by examining query results. The browser, based on the
magnifying glass metaphor, allows users to move a filter over
datasets displayed against a background map, while on the fly
changing non-spatial parameters that determine what datasets will
be visible in the magnifying glass.