Generating evacuation polygons based on an indoor shortest path

Architects and transportation planners, for example, need to plan where and how many exits a building will require based on various standards and safety policies. After a building is built, a facility manager and security team usually do not have access to this information. Imagine that there is an event to be planned and you want to see what areas can be evacuated within a certain time, which are constrained by your list of exits in the building.

During this exercise, we want to create some polygons for a specific start point inside a major building, showing which areas can be evacuated in 10, 20, 30, and 60 second intervals. We assume that people will walk at 5 km/hr or 1.39 m/s, which is their normal walking speed. If we panic and run, our normal run speed increases to 6.7 m/s or 24.12 km/hr.

Our results are going to generate a set of polygons representing our evacuation zones based on the building hallways. We need to define...