SPECIAL SESSION(S): Agent-Based Models and Geographical Systems  LOCATION AND DATESAssociation of American Geographers Annual MeetingFebruary, 24-28th, 2012, New York, USA  DESCRIPTION Agent-based modeling (ABM) within geographical systems is starting to mature as a methodology in geography and across the social sciences. The aim of this session(s) is to bring together researchers utilizing agent-based models (and associated methodologies) to discuss topics relating to: theory, technical issues and applications domains of ABM within geographical systems. We would particularly welcome papers relating to: •              Validation, verification and calibration of Agent-based models•              Hybrid modeling approaches (e.g. utilizing Cellular Automata, Spatial Interaction, Microsimulation, etc.)•              Handling scale and space issues•              Visualization of agent-based models (along with their outputs)•              Handling scale and space issues•              Ways of representing behavior within models of geographical systems•              Participatory modeling and simulation•              Applications: Ranging from the micro to macro scale Please e-mail the abstract and key words with your expression of intent to Alison Heppenstall A.J.Heppenstall@leeds.ac.uk by September 15th, 2011. Please make sure that your abstract conforms to the AAG guidelines in relation to title, word limit and key words and as specified at http://www.aag.org/cs/annualmeeting/call_for_papers/abstract_guidelines. An abstract should be no more than 250 words that describes the presentation’s purpose, methods, and conclusions as well as to include keywords. Full submissions will be given priority over submissions with just a paper title. We are currently investigating journals (e.g. Environment and Planning B) in order to widely disseminate the ideas emerging from this session(s).  Authors will have the opportunity to suitably revise their presentations for publication. ORGANIZERS: Alison Heppenstall, School of Geography, University of Leeds, Leeds, UK A.J.Heppenstall@leeds.ac.uk. Andrew Crooks,Krasnow Institute for Advanced Study, George Mason University, USA, acrooks2@gmu.edu Linda See, International Institute of Applied Systems Analysis (IIASA), Laxenburg, Austria <see@iiasa.ac.at > Mark Birkin, School of Geography, University of Leeds, Leeds, UK M.H.Birkin@leeds.ac.uk. Michael Batty, Centre for Advanced Spatial Analysis (CASA), University College London, London, UK m.batty@ucl.ac.uk   TIMELINE: September 15th, 2011:Abstract submission and expression of intent to session organizers. E-mail Alison Heppenstall A.J.Heppenstall@leeds.ac.uk by this date if you are interested in being in this session. Please submit an abstract and key words with your expression of intent. Full submissions will be given priority over submissions with just a paper title. September 22th, 2011:Session finalization. Session organizers determine session order and content and notify authors. September 26th, 2011:Final abstract submission to AAG, via www.aag.org. All participants must register individually via this site. Upon registration you will be given a participant number (PIN). Send the PIN and a copy of your final abstract to Alison Heppenstall A.J.Heppenstall@leeds.ac.uk. Neither the organizers nor the AAG will edit the abstracts. September 28th, 2011:AAG registration deadline. Sessions submitted to AAG for approval. February 24-28th, 2012: AAG meeting, New York, USA