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Procedural Modeling of Cities
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As the capability of display platforms improves, generating realistic
content to realize the potential of these platforms becomes increasingly
challenging. Modelers need tools to help them generate realistic content.
Tools for the modeling of natural objects such as plants are well-researched,
but man-made objects have been largely overlooked. We are working on tools
for the generation of realistic cities. Our approach uses agent-based
simulation.
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Sections
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Cities CORE Model - Cultivation Of Realistic Environments
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One major fruit of this project is a highly complex model, which simulates
land-usage and growth patterns of cities.
The Cities CORE model provides
capabilities for comprehensive city creation, both by generating urban landscapes
automatically from seeds, and by user-directed development that enables
interactivity in the city creation process.
It is written using the NetLogo
environment and modeling language, and is comprised of almost ten thousand lines of code.
We are publicly releasing this model as a contribution to urban modeling research.
Further information is available on the Cities CORE Model Page.
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Extending the Cities CORE model
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No model, however intricate or complex it may be, is the final word on a subject.
There are always numerous avenues for extending the model, to take additional
facets of the situation into account, to measure results using different metrics,
or to integrate with other tools.
To this end, we show how the Cities CORE model can be extended in one particular direction -- namely,
the ability to import transportation networks that are created using other programs and algorithms.
We also created a NetLogo model called the "Road Grid Builder", which provides convenient tools for
building road networks, which can then be imported into the Cities CORE model for simulated growth.
Our intent is that this example may offer a path for others to develop similar "plugin" type
extensions to the Cities CORE model, to improve its functionality and create synergistic
interactions with other urban modeling and statistical tools. By releasing the source code
for the CITIES Core model (and the Road Grid Builder extension model), it becomes possible for
researchers from across the world to build enhancements to the model.
For a demonstration of this extension, and how to use it, see the Road Network Builder Page.
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Urban Modeling Suite
Through our work on this project, we have formed the opinion that a series of
simple models which focus on modeling different aspects of urban development
can provide a better understanding of the underlying processes than combining all
of the aspects into a single monolithic model. In particular, this has proved
to be the case in pedagogical settings. Accordingly, we have put together a
suite of models which spans the broad spectrum of topics relevant to urban planning.
Several of these models were originally authored by undergraduate students in
the "Sprawl / Swarm" course at Illinois Institute of Technology in Fall 2006,
under the supervision of Sarah Dunn and Martin Felsen. Others were created by
members of this project for the purpose of illustrating a particular concept, such
as the Positive Feedback model which replicates a model described the book
Cities and Complexity, written by Michael Batty.
In the table below, click on the names at left to go to a page that allows you run each model as a Java applet
in your web browser, and also contains documentation about each model.
Click on the thumbnails on the right to view a larger screenshot taken from the model.
Note: Some of the screenshots were taken using a NetLogo feature that allows
for a three-dimensional perspective view of a two-dimensional model. This feature is not available
from the applet versions of the models, but it is available if you download the model files and open
them using NetLogo (version 4 or higher).
Positive Feedback
This model looks at the general concept of positive feedback, which is a prevalent phenomenon in many areas of urban development,
and is crucial to understanding growth patterns.
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Path Dependence
This model examines positive feedback as it pertains to the concept of "path dependence" as explained by W. Brian Arthur in his paper, "Urban Systems and Path Dependence", as well as other papers.
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Structure from Randomness 1
This model demonstrates how identifiable structure can form out of random inital conditions, under a simple process.
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Structure from Randomness 2
This is a second model showing how structure can form out of randomness.
Both of these models are implementations of models found in Michael Batty's book "Cities and Complexity".
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Cells
This model explores 2-D cellular automata and as an introduction to spatial dynamics and growth of complex shapes from simple rules.
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Pollution
This model studies the balance between the creation and remediation of pollution by agents in a simple simulated environment.
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Awareness
This model simulates points of information and/or resource exchange in an urban environment,
and examines the spread of the concept or resource through a population of agents.
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Recycling
This model demonstrates relationships of agents (people) trying to sustain their natural resource of land over the course of time.
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Sprawl Effect
This model demonstrates a simplified version of city growth and how it leads to urban sprawl and the problems connected with it (e.g. leapfrogging).
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Economic Disparity
This model examines residential land-usage patterns from an economic perspective, using the socio-economic status of the agents to determine their preferences for choosing a location to live.
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Tijuana Bordertowns
This model simulates various socio-economic realities of low-income residents of the City of Tijuana for the purpose of creating propositional design interventions.
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The Urban Suite is being included as an official set of curricular models in the NetLogo 4.0
release. This means that rather than downloading them from this web site, the Urban Suite models
will be readily available in the "Model Library" for all NetLogo users.
Although we have not created a full curriculum to surround these models,
we have organized the suite in a natural progression from simple concepts to
more advanced models. The models are each accompanied by extensive documentation,
which is available in the Information tab, from within the NetLogo software, and
also available on the model web pages linked to below.
The documentation serves
as a tutorial for those desiring to learn more about the agent-based modeling of
urban development. The documentation covers, for each model: what is being modeled,
how it works (the rules of the agents), how to use the model, what to notice about the model,
and some ideas for exploring the models behavior more deeply.
It offers ideas for how the model could be extended, and some tips on tricks
about using the NetLogo modeling language. Lastly, the documentation includes
pointers to related resources (such as other similar models), and provides credit to
the models authors, and cites references in the cases where the model is implementing
ideas or models taken from previous academic work in this field.
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Project Members & Sponsors
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Principal Investigators:
Uri Wilensky (NU LS/CS),
Ben Watson (NC State), &
Martin Felsen (IIT & UrbanLab).
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| Other project members:
Craig Brozefsky (NU CCL),
Tom Lechner (NU CS),
Andy Moddrell (IIT).
William Rand (NU NICO),
Forrest Stonedahl (NU CS),
Seth Tisue (NU CCL),
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| Sponsors:
NSF ITR award 0326542,
Electronic Arts &
Maxis.
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| Thanks to:
the Center for Connected Learning and Computer-Based Modeling,
the chil.us project,
the Environmental Simulation Center,
John Buchanan,
Christopher Alexander &
Michael Shiffer.
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Publications and Presentations
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Felsen, M. (2007). "Complex Populations," in MODELS, 306090 Books, Volume 11, Emily Abruzzo, Jonathan D. Solomon, Eric Ellingsen editors.
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Felsen, M. (2007) "Practice, Criticism, Research and Design in Architectural Education".
Paper presnted at a special joint session of the 2007 Association of Collegiate Schools of Architecture (ACSA) Cranbrook Teachers Seminar and the American Institute of Architects (AIA) Educator Practitioner Network Institute Conference:
Integrated Practice and the Twenty-First Century Curriculum, June 28 - July 1, 2007 at Cranbrook Academy of Art in Bloomfield Hills, Michigan.
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Rand, W., & Wilensky, U. (2007). Full-Spectrum Modeling: From Simplicity to Elaboration and Realism in Urban Pattern Formation.
Paper presented at the North American Association Computational Social and Organization Sciences conference (NAACSOS), Atlanta, GA.
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Sexton, C. & Watson, B.A. (2007). "Vectorization of gridded urban land
use data." ACM SIGGRAPH Conference Poster.
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| Tisue, S. (2007). What's New in NetLogo. Talk presented at Swarmfest 2007, Chicago, IL, July 2007.
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Watson, B.A., Mueller, P., Wonka, P., & Fuller, A. (2007). "Urban design
and procedural modeling." Half-day tutorial, ACM SIGGRAPH Conference.
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Blikstein, P., & Wilensky, U. (2006). 'Hybrid modeling': Advanced scientific
investigation linking computer models and real-world sensing. Paper presented at the Seventh International
Conference of the Learning Sciences, Bloomington, IL, June 27-July 1.
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| Felsen, M., Watson, B., & Wilensky, U. (2006). Urban Complexity + Emergence:
Procedural Modeling of City Activity and Form. In Surfacing Urbanisms: Recent
Approaches to Metropolitan Design (pp. 261-265). Pasadena, CA: Woodbury University.
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| Lechner, T., Watson, B., Ren, P., Wilensky, U., Tisue, S., &
Felsen, M. (2006). Procedural modeling of urban land use. ACM SIGGRAPH 2006 conference.
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| Rand, W., Blikstein, P., & Wilensky, U. (2006). Widgets, Planets,
and Demons: the Case for the Integration of Human, Embedded, and Virtual Agents
via Mediation. Paper presented at Swarmfest 2006, South Bend, IN, June 2006.
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| Rand, W., & Wilensky, U. (2006). NetLogo 3.1: Low Threshold,
No Ceiling. Paper presented at NAACSOS 2006, South Bend, IN, June 2006.
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Rand, W., & Wilensky, U. (2006). Verification and Validation through Replication: A Case Study Using Axelrod and Hammond's Ethnocetnrism Model. Paper presented at NAACSOS 2006, South Bend, IN, June 2006.
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"Research: Building from the Web Up," Illinois Institute of Technology Magazine (Fall 2006): 12.
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| Sondahl, F., Tisue, S., & Wilensky, U. (2006).
Breeding faster turtles: Progress towards a NetLogo compiler. Paper presented at Agent 2006, Chicago, IL.
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Wilensky, U. (2006). Complex systems and restructuration of scientific disciplines: Implications for learning, analysis of social systems, and educational policy. In J. Kolodner (Chair), C. Bereiter (Discussant), and J.D. Bransford (Discussant), �Complex Systems, Learning, and Education: Conceptual Principles, Methodologies, and Implications for Educational Research. Paper presented at the annual meeting of the American Educational Research Association, San Francisco, CA, April 7-11.
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Wilensky, U. (2006). "Emergent Modeling." Plenary talk at the International Conference on Complexity Sciences. Boston, Ma. (June 2006).
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| Wilensky, U. (2006). Promoting ABM literacy:
implications for design, scientific content and education. Keynote Paper presented at Agent 2006, Chicago, IL.
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| Wilensky, U., Rand, W., & Blikstein, P. (2006). Participatory,
Embodied, Multi-Agent Simulation. Paper presented at the AAMAS-06 Conference, 2006.
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Felsen, M. (2005). "Modeling of Urban Activity and Form," Annual Research Report from the Illinois Institute of Technology (2005): 5.
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| Tisue, S., & Wilensky, U. (2004a). NetLogo: Design and implementation of a
multi-agent modeling landscape. Paper presented at the Swarmfest, Ann Arbor, MI, May 9-11.
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| Tisue, S., & Wilensky, U. (2004). NetLogo: A simple environment for
modeling complexity. Paper presented at the International Conference on Complex Systems (ICCS 2004), Boston, MA, May 16-21.
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| Tisue, S., & Wilensky, U. (2004). NetLogo: Design and
implementation of a multi-agent modeling environment. Paper presented at the Agent 2004 conference,
Chicago, IL, October 2004. (This is a combined, revised, and updated version of our ICCS and SwarmFest papers from earlier in 2004.)
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| T. Lechner, B.A. Watson, S. Tisue, U. Wilensky & M. Felsen (2004).
Procedural modeling of land use in cities (pdf).
Technical report NWU-CS-04-38. |
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Wilensky, U. (2004). "Complexity Perspectives and Multi-agent Modeling in Education." Plenary talk at the International Conference on Complexity Sciences. Boston, Ma. (May 2004).
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| T. Lechner, B.A. Watson, U. Wilensky & M. Felsen (2003).
Proceduring city modeling (pdf).
1st Midwestern Graphics Conference (St. Louis, MO).
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