The article by Haklay et al. from 2001 is an interesting look into simulated pedestrian movement in a closed-system urban downtown setting. Named STREETS, this module-based model shows just how complex real human movement is by detailing the ways our unconscious decision-making must be broken down by a computer in order to simply approximate pedestrian paths.
After reading about the various modules, my thoughts were immediately distracted by trying to think up further additions to make the model as realistic as possible. A more complex model might include the presence of cars as another variable that would affect how pedestrians are able to cross roads, and for example, how their path might change if the time spent waiting for cars to go by allows them to focus on an alternate target destination that they originally ignored. In relation to my own project on hydrological models, the simplest Mover module could be applied to predicting overflow in river systems. If excess water flow units were given values like individual agents in the article, and the water filled certain pixels like pedestrians filled sidewalk cells, once a pixel was “full”, the excess water would have to move into the adjacent pixel and could change overflow paths.
As the modules became more specific in their control of agent movement, the final module, Planner, almost seemed like artificial intelligence. It was not until the authors directly address the difference between deliberate simulation and emergent, ‘self-organizing’ movement that I realized model simulation can become so much closer to “real-life” than exists currently. Overall, this piece was engaging and had easy-to-follow technical descriptions of the modules combined with just enough theory to relate the topic to GIScience and future implications.
– Vdev