The Depiction platform was created with the intention of allowing domain experts to integrate simulation models into custom elements to enable access of state-of-the-art simulations to the everyday user. The models in our initial retail version – such as flooding, runoff, plume distribution, evacuation routing, and signal propagation – demonstrate the power of simulations in visualizing ‘what if’ scenarios in the geographic domain.

The integration of an industry-standard simulation models, we believe, will enhance the usefulness of our modest tool. To that end, we have been eyeing programs such as ALOHA. An industry standard for modeling dispersion of hazardous chemicals, the ALOHA program was developed jointly by the National Oceanic and Atmospheric Administration (NOAA) and the Environmental Protection Agency (EPA). Available freely, this program has over 50,000 users in government and industry, and the accompanying CAMEO suite of software has had over 250,000 downloads since 2001.

A growing number of Depiction users have been requesting integration of ALOHA plume outputs with Depiction. We listened and now are working toward that…

Our initial stab at this integration, currently undergoing development, is strictly one-way — ALOHA is run separately; it produces the Threat Zones; Depiction reads the relevant files and brings in the data as a Depiction element. Once in Depiction, this element will be a first-class citizen, endowed with full rights to interact with other elements, disable buildings, knock out people, what have you. You, as the user, decide what this Threat Zone should do via the Interaction rules accessible via the SETTINGS menu.

Note: Just to reemphasize, the ALOHA integration functionality is not currently present in Depiction. This is an internal version that will be available in the near future to our users.

Almost a year ago, I did this post: http://www.depiction.com/PhiladelphiaRefineryScenario that depicts the fictitious account of a terrorist attack in Philadelphia, described in Stephen Flynn’s “Edge of Distaster.” I revisited that story, this time replacing the Depiction Plume element with the output of ALOHA. This is what I did.

Run ALOHA

  • First, I downloaded the ALOHA program from http://www.epa.gov/oem/content/cameo/aloha.htm
  • Created a planning scenario in ALOHA with HFl (as described in Flynn’s book), with the following parameters that more or less approximate the conditions described in the book.
  • Weather: wind from the NW at 6 mph; no cloud cover; dry day; temperature at 65 F (would that be a fair guess given it is a late June day in Philly?).
  • Chemical properties: Hydrogen Fluoride; leak from a hole in a cylindrical tank; volume 117504 gallons (again, I have no idea what this should be…that’s up to you folks knowledgeable about Hazmat).
  • Threat Zones at 44 ppm, 24 ppm, and 1 ppm at 60 minutes.

Run Depiction

  • I reopened the DPN file from that scenario created last year. This DPN is available from http://www.depiction.com/downloads under the heading ‘Edge of Distaster.’
  • Couple of points: first, features such as permanent hover text, better-stylized annotations, and easy editing of shapes (the boundary of the Conoco refinery is depicted as a user-drawn polygon) shows the progress the app has made from 1.0 to 1.2; secondly, the presence of NAIP satellite imagery for background tilling is a huge plus. A year ago, I had to obtain hi-res images from Google Earth and manually geo-align them. Now, don’t get me wrong. Geo-aligning (especially in Depiction) is a fun process. Kind of like creating art. But NAIP imagery just allowed me to focus on the task at hand. Nice addition, I’d say.
  • I deleted the two Plumes in that story, one depicting plume at one hour elapsed time and the second one for the two-hour progress. Instead, I now chose the ALOHA PLUME element from the Quickadd Toolbar and drop it at the appropriate location.
  • Depiction reads the ALOHA Threat Zone file and plops the Threat Zones into my story.
  • Here is how it looks:

"Edge of Disaster" scenario with plume output from ALOHA (click to view full size)

Observations

There are three threat zones (that’s the most ALOHA can produce) and corresponding Confidence Lines here. The Red threat zone demarcates the region where the toxic concentration of HFl is at 44 ppm. You get this information when you mouse over the red threat zone. The orange threat zone is at 24 ppm and the yellow threat zone is at 1 ppm. The confidence line associated with each threat zone captures the wider region within which the threat exists with 95% probability. This takes into account uncertainties in terms of wind speed and direction.

Other threat zones (three at a time) can be generated from ALOHA using user-specified ppm limits.

Communication with ALOHA

The next steps would involve communicating directly with ALOHA. This effort would allow the user to control ALOHA from inside Depiction. The user would be able to choose the chemical, specify the threat zone parameters, and be able to better control ALOHA output without switching back and forth between the two programs.

It is highly likely that we will first introduce the one-way ALOHA integration described in this example and then work toward a more tight integration.