Monday, February 15, 2016

Pedestrian model of agents exiting a building

I built a model of pedestrians who try to leave the floor through one or two exits. The map being used is from GMU’s Krasnow Institute. The model records the frequency of each cell being chosen as a path and draws the result into a path graph, which can be exported to ArcGIS for further analysis.

Here is a graph showing the path graph opened in ArcGIS:  

Here is a video showing the simulation process:

Each pacth has a variable called elevation, which is determined by (1) the shortest distance to the exit; (2)if it is in a room, elevation is lower being closer to gate. If there are more than one exit patches, the elevation is equal to the shortest distance to closest one of the exit patches. People use the gravity model (always flow to lower elevation, if space is available) to move to the exit.

In this model, the “elevation” of a patch is decided by its distance to exits as well as how close it is located to the gate of the room, so that people can run out if rooms. When running the model, people always try to move to lower elevation. This algorithm can also be used to build a rainfall model to analyze the movement of rain drops on the ground. See this link for the Rainfall model. (

I have also added the export function to export the path frequency graph to an asc file. You may open the file in ArcGIS for further analysis.

Here is the code:

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