Urban Suite - Cells Model

The applet (below) requires Java 1.4.1 or higher. It will not run on Windows 95 or Mac OS 8 or 9. Mac users must have OS X 10.2.6 or higher and use a browser that supports Java 1.4. (Safari works, IE does not.) On other operating systems, you may obtain the latest Java plugin from Sun's Java site.

Download this model file, and use NetLogo to run or edit it: Urban Suite - Cells.nlogo

WHAT IS IT?

This is a model of 2d cellular automata. It uses very simple rules to grow a form. These forms may be very complex, or highly regular.

HOW IT WORKS

At each step, each patch looks to see if it satifies the rules defined for being turned on. The rule is defined by the NEIGHBORHOOD chooser and the N-COUNT chooser. If the number of currently turned on patches in the NEIGHBORHOOD around the patch is non-zero and also satifies N-COUNT, then that patch has a chance to turn. The change to turn on is defind by the PROBABILITY slider. If AGE-LIMIT is non-zero, then any patches that have been turned on for more ticks than AGE-LIMIT will be turned off.

The patches color shows their age, with darker patches being older than lighter patches.

HOW TO USE IT

Press SETUP to clear the board and create the initial seed patch. Optionally, you may also press the RANDOM SEED button to crete another seed in a random location.

Press the GO * 80 button and the model will run thru 80 ticks. You may also press the STEP button to advance the model a single tick. Lastly, the GO button will run the model an unlimited number of ticks, until it is pressed again.

The NEIGHBORS and N-COUNT choosers define the rule used to determine if a patch turns on or not, see the HOW IT WORKS section for details.

PROBABILITY is the chance a patch has of turning on if it satifis the current rule.

AGE-LIMIT is the number of ticks a patch will stay turned on. if AGE-LIMIT is 0, then there is no AGE-LIMIT defined and turned on patches stay that way forever.

The CYCLE COLORS button will make all turned on patches to cycle their colors.

The LIVE CELLS plot is a plot of the patches that are turned on at each tick.

THINGS TO NOTICE

Which rules produce the most complex shape?

How many ticks does it take for the rules to fill up the world?

THINGS TO TRY

Some rules will result in a form that grows and fills the whole space, while others will have empty spots in them.

If you play with the PROBABILITY slider you can get assymetrical forms, and also cause "mutations" in the growth of a form that would otherwise stop growing after a set number of ticks. Such mutations can grow to fill in more patchs because of the irregulaity

EXTENDING THE MODEL

Add new neighborhoods to the NEIGHBORHOODS chooser. You can do this by writing a reporter with the same name as your new neighborhood and adding the name to the chooser.

NETLOGO FEATURES

The scale-color primitive is used to set the color of patches according to their age.

RELATED MODELS

This model is related to all of the other models in the "Urban Suite".

This model is also similar to the models in the Computer Science/Cellular Automata section of the NetLogo models library.

CREDITS AND REFERENCES

This model was authored by Craig Brozefsky of the Center for Connected Learning and Computer-Based Modeling. It is based from the models described in chapter 2 of the book "Cities and Complexity" by Michael Batty.

The Urban Suite models were developed as part of the Procedural Modeling of Cities project, under the sponsorship of NSF ITR award 0326542, Electronic Arts & Maxis.

Please see the project web site ( http://ccl.northwestern.edu/cities/ ) for more information.

To refer to this model in academic publications, please use: Wilensky, U. (2007). NetLogo Urban Suite - Cells model. http://ccl.northwestern.edu/netlogo/models/UrbanSuite-Cells. Center for Connected Learning and Computer-Based Modeling, Northwestern University, Evanston, IL.

Back to the Main Cities Project Web Site.