One of the compelling uses of Depiction is in narrating a story in a geographical context and weaving ‘what-if’ scenarios on top of it. Of late, I have been revisiting Stephen Flynn’s Edge of Disaster, (see http://www.cfr.org/publication/12380/) whose view of emergency preparedness and building resiliency mirrors mine. Some of the scenarios outlined in the book, while remaining plausible, also take the tone and pacing of an action thriller. They’re exciting to read and make me continually try to visually reconstruct the scenario in my head – a task for which my head isn’t geared. Well, could I use Depiction to reconstruct these scenarios visually? If so, how long would that take?

The answers: yes and 10 minutes.

The book opens with a scenario set in Philadelphia. While my natural impulse is to shy away from describing uses of our app that involve acts of terrorism (even if it empowers our community to be better prepared), Flynn articulates the reason why we must discuss vulnerabilities more openly:

"The only way to muster the political will to reduce our exposure to malicious acts is to acknowledge our weaknesses and to openly discuss the options for addressing them."

Back to the Philadelphia scenario. It involves terrorists detonating explosives near a storage tank in the Sunoco refinery, causing secondary explosions to form a cloud of anhydrous hydrogen fluoride. A westerly light wind then forces this cloud to move eastward past the neighborhood to the north of Roosevelt park and head toward the Citizens Bank stadium where 40,000 people are watching a Phillies-Mets game. Interstate 95 is congested from weekend traffic and Interstate 76 has been shutdown so that emergency vehicles can get to the refinery. In short, a scenario ripe for representing and exploring in Depiction.

I started a Philadelphia story in no time in Depiction. Chose Road network (OpenStreetMaps), Imagery (Terraserver) satellite imagery, Water Bodies (US Census), and Weather Forecast (NOAA 24-hour) from the Quickstart data sources at startup. They all came in fine.

I was not satisfied with the imagery from Terraserver, so I screen-grabbed some Google Earth images and brought them into Depiction. The Google Earth images needed to be geo-aligned. Truth be told, I had fun geo-aligning them. More fun than should be allowed during the execution of fairly mundane tasks. There were two high-resolution images, one around the Sunoco facility and the other one around the ballpark.

After getting all the background (satellite imagery, maps, etc.) and backdrop (road networks, weather data) data, it was now time to bring in the "active" Depiction elements – elements that interact and make the scenario come alive.

I started with a User-drawn shape to demarcate, roughly, the perimeter of the refinery. Although I didn’t design the refinery perimeter to take part in any active interactions, it served as a nice visual representation of the affected area around the Sunoco facility. I dropped a Plume element at the point of attack, set its parameters (time duration: 1 hour, wind direction: 315 degrees, speed: 6mph). I added another Plume element and set this one’s time parameter to two hours. I set up a temporary medical facility to illustrate how Depiction interactively disables the facility (marks it visually with a big, red "X") because it lay in the path of the plume. This would indicate to the planner that this facility is no longer operational under this "what if" scenario.

Visualizing both plumes in the background rendered the map a little unreadable. The Roosevelt park and the blue collar neighborhood to its north were better visualized when only the 1-hour plume was visible. So, I decided to visualize the 2-hour plume inside a revealer – a great visual gadget that minimizes clutter.

I used the default Road Barrier element from the Depiction toolbox, modified its parameters, changed its name and used it to represent congestion on Interstate 95 and a closure on Interstate 76. I brought in some hospitals into the Depiction (Google search hospitals in Philadelphia and type in their addresses in Depiction). I dropped in some dynamic routes to ferry the injured from the refinery as well as from the baseball stadium vicinity.

This is where the power of Depiction is most manifest. Those traffic congestions and road closures actually influence the calculated routes. You can move those elements and the route will re-calculate automatically. There is a rule that says Plume modifies road network (click on the Interactions menu option and you’ll see it). Even if it weren’t there, you could create your own rules to effect the changes you’d like to see. That temporary medical facility got disabled by the plume because there’s a default rule that ships with Depiction that says a Plume causes an effect such as disabling elements of type building. When our SDK is released this month, it would also be possible, for instance, to use the wind speed/direction properties of the Weather forecast (NOAA 24-hour) element to drive the plume element’s behavior.

A colleague comes over and says "What if there is an accident at 13th and Bigler?" I drop in a Road Barrier element, change some parameters and a previous route now modifies to avoid routing through that intersection. I mouse-over the modified route and it reveals the new distance to be 1.34 miles to Methodist hospital. "What would happen to the plume in three hours?", another colleague asks.

A rich discourse ensues.