International Archives of the Photogrammetry, Remote
occur rapidly, such nodes can be identified using red (or other
bright colors). It accuracy metadata are also available, this
could be expressed in the relative crispness or fuzziness of the
node and prong representations (Pang, Wittenbrink et al. 1997).
These future extensions of our model are expected to be useful
in alerting users to potential situations where merging or
splitting heliXes might be helpful.
In addition to visual representations of helixes, we are also
working on utilizing aggregation and splitting techniques when
dealing with text and other data formats that may be associated
with the helixes. These formats can complement and enhance
the helixes. As an example, we might have metadata about
accuracy. The level of metadata that deals with specific
horizontal and vertical accuracies of angles is quite detailed.
The FGDC lists a set of standard metadata that is set up in a
hierarchical fashion. By exploiting this construction we can
gradually zoom in to the level of detail that is required, both
within the data itself and within the corresponding metadata
(Eickhorst 2002; Eickhorst and Agouris 2002). Thus, the user
would not need to actually see metadata on accuracy or fuzzy
visualizations until a very detailed view of the helix itself is
desired. Integrating this capability into our helix model is a
future goal of our research.
8. CONCLUSIONS
Spatiotemporal helixes represent a new and promising theory
for modelling and analyzing change in geospatial applications
and other large-scale data-intensive projects in various fields. In
this paper, we have presented our work on the theories of
helixes and similarity metrics, and have given examples of how
these theories can be implemented. We have presented
examples of the experiments being conducted to test the
robustness of our methods. Finally, we discussed some new
directions that we are currently pursuing. These extensions will
result in the development of a comprehensive model that will
support users querying on object behaviour over time, using an
easily understandable interface.
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Agouris, P. and A. Stefanidis (2003). Efficient Summarization
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ACKNOWLEDGEMENTS
This work is supported by the National Science Foundation
through grants. DG-9983432 and ITR-0121269 and by the
National Geospatial-Intelligence Agency (NGA) through NMA
401-02-1-2008. Kristin Eickhorsts work has also been funded
in part by NASA through a Maine Space Grant Fellowship, and
the generous support of Goddard Space Flight Center.
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