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| DEEP
DETAIL. Graphics on South Carolina evacuation site connect
many layers of data. (Image courtesy of Intergraph Geospatial
Solutions) |
South Carolina transportation
and emergency officials have fired up a new system for managing
evacuations. It assembles near real-time traffic data from around
the state and distributes it rapidly through a powerful Web
interface.
"It just takes seconds now to get the data," says
Donald McElveen, SCDOT’s manager of geographic information
systems and mapping. He says the tool lets officials compare
evacuation traffic to normal, watch for slow-downs and decide
if alternative routes should be opened or lane directions
reversed to relieve congestion.
The system was built by Intergraph
Geospatial Solutions, Huntsville, Ala. It replaces an earlier
one also built by Intergraph, in 1999. Both use data from
sensors buried in lanes around the state.
Previously, data was accessed in
spreadsheets by regions of the state. It had to be downloaded,
merged and analyzed as precious time ticked off the clock.
The new system uses a Web interface to almost instantly deliver
information, sort it and assemble it into highly nuanced reports,
charts and maps, including weather overlays.
The improvements came on line in
June. They were road tested through Hurricane Charley and
Tropical Storm Gaston last month. "It did very well,"
says McElveen.
Sensors automatically report lane-by-lane
traffic volume and speed for hundreds of locations hourly.
Software compares readings to past records at those places
to track capacity. Anomalies, such as lanes with dropping
speed or volume, can be called out through sorts.
Much of the system’s power
and ease of use is in the speed and flexibility with which
it delivers information. Through a rising-star format called
Scalable Vector Graphics, highly compressed images of charts
and maps are downloaded with embedded detail that is revealed
by zooming in, or passing over triggers with a curser. Unlike
other image formats, svg image resolution is scalable and
doesn’t degrade with enlargement. Layers can be turned
on and off. The only software needed is a small plug-in from
Adobe, available for free over the Internet.
The state-wide evacuation route
map, for instance, can be zoomed again and again, with no
additional downloads, to reveal nodes of detail, such as individual
Automatic Traffic Reporting Stations and cameras. Clicking
on an ATR generates a report of its current and historic data.
Clicking on a camera brings its live view. ATRs can also be
accessed by clicking on buttons and drop down menus.
"It gives you an idea of what
you can do with the Web now in terms of svg graphics,"
says McElveen. "This was a major update compared to what
we had."
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