New book! ABM and GIS

Coming in January 2019…!   Buy it hereScreenshot 2018-12-03 16.08.56

This is the era of Big Data and computational social science. It is an era that requires tools which can do more than visualise data but also model the complex relation between data and human action and interaction. Agent-Based Models (ABM) – computational models which simulate human action and interaction – do just that.

This textbook explains how to design and build ABM and how to link the models to Geographical Information Systems. It guides you from the basics through to constructing more complex models which work with data and human behaviour in a spatial context. All of the fundamental concepts are explained and related to practical examples to facilitate learning (with models developed in NetLogo with all code examples available on the accompanying website).  You will be able to use these models to develop your own applications and link, where appropriate, to Geographical Information Systems.

All of the key ideas and methods are explained in detail:

  • geographical modelling;
  • an introduction to ABM;
  • the fundamentals of Geographical Information Science;
  • why ABM and GIS;
  • using QGIS;
  • designing and building an ABM;
  • calibration and validation;
  • modelling human behaviour;
  • visualisation and 3D ABM;
  • using Big Geosocial Data, GIS and ABM.

An applied primer, that provides fundamental knowledge and practical skills, it will provide you with the skills to build and run your own models, and to begin your own research projects.

Advertisements

ABM Congress, Washington

abmcongressI attended the International Congress on Agent Computing at George Mason University (US) last month.  It was organised to mark the 20th anniversary of the publication of Robert Axtell and Joshua Epstein‘s landmark work,  Growing Artificial Societies and as such was both a celebration and a reflection on how far the discipline has progressed over the last 20 years.

While it is clear that in some areas there has been great gains, such as the size and complexity of ABMs (not to mention the sheer number of applications – Robert Axtell in his presentation gave the following figures based on a keyword search of publications: 1K papers per year on IBM; 10K per year on MAS and 5K per year on ABM), I see these gains as mainly attributable to advances in software and availability of data and not because we are tackling the big methodological problems.  I would strongly agree with Axtell that ABMs are still ‘laboratory animals’ and not yet ready for uptake in policy.  This view surprisingly contrasted with Epstein who in his opening remarks described ABM as a ‘mature scientific instrument’, perhaps nodding towards the large numbers of (often bad) ABMs that are continually appearing.  However, Epstein did agree with Axtell in the discussion of several challenges/definitive work that ABM needs to take on such as creating cognitively plausible agents (accompanied by a big plug for Epstein’s recent book, Agent Zero, on this very topic), not getting side stepped by big data:  “Data should be as big as necessary, but no bigger” (a nice play on the Einstein ‘models should be as simple as possible, but no simpler’) and calibrating to large scale ABMs.

It is this last point, that of calibration and validation that can be blamed for my grumpy mood throughout most of the Congress presentations.  There was some fantastic work, creating very complex agents and environments, but these models were calibrated and validated using simple statistics such as R^2!  Complex models = (often) complex results, which in turn requires complex analysis tools.  By the time that my presentation time came around on the last afternoon, I was in the mood for a bit of a rant…which is exactly what I did! But I’d like to think I did it in a professional way…  I presented a joint talk with Andrew Crooks and Nick Malleson entitled “ABM for Simulating Spatial Systems: How are we doing?” which reflected on how well (or not) ABM of geographical systems has advanced over the last 20 years.

growthofgis

 

We argued that while as geographers we are very good at handling space (due to GIS), we’re not very good at representing the relationships and interactions (human to human and human to environment).  We also need to look closely at how to scale up individual agents; for example how can we take an agent created at the neighbourhood level, with its own rules and explicit use of space and scale this up to the city level (preserving all the characteristics and behaviours of that agent)?  Work needs to be done now to shape how we use Big Data to ensure that it becomes an asset to ABM, not a burden.  And then I moved on to calibration and validation!  It wasn’t all gloom, the presentation featured lots of eye candy thanks to Nick and Andrew.

While the congress brought together an interesting line up of interdisciplinary keynote speakers: Brian ArthurMike BattyStuart Kauffman and  David Krakauer  – all were men.  Of the 19 posters and 59 presentations,  only a handful were women.  I find this lack of diversity disappointing (I refer here to gender, but this could equally be applied to other aspects of diversity).  While women are in the minority in this discipline, we do have a presence and such an event reflecting on the past, and celebrating a promising future should have fully reflected this.

However, I don’t wish to end on a negative note, the Congress was fantastic in the breadth of work that it showcased, and because it was so small, it had a genuinely friendly and engaging feel to it.  The last word should go to Epstein who I felt summarised up ABM nicely with the following: “As a young science, [it has made] tremendous progress and [has great] momentum”.

Reference: 

Heppenstall, A., Crooks A.T. and Malleson, N. (2016)ABM for Simulating Spatial Systems: How are we doing? International Congress on Agent Computing, 29th-30th, November, Fairfax, VA.

RGS: Call for papers!

Fancy coming to London at the end of August?  Looking for an exciting Geocomp session to show off your fancy research?  Look no further…

Call for papers:  **GeoComputation; the next 20 years**

We would like to invite abstracts for a session about the future or GeoComputation at the Royal Geographical Society Annual International Conference 2016 (RGS 2016) in London, Tuesday 30 August to Friday 2 September 2016.

Session outline: The use of fully programmable computers to construct spatial models and run spatial analyses stretches back to the use of ENIAC to calculate ballistic courses during the Second World War. As ENIAC was announced to the public in 1946, 2016 represents the 70th year of the public use of computers in geography. Perhaps more happily, it is also 20 years since the term “GeoComputation” was invented to draw together a disparate set of geographers doing computing in the 70s, 80s, and 90s at the 1996 “1st International Conference on GeoComputation” in Leeds, UK. In 2017, the community built around this conference will be celebrating its 21st birthday, reflecting on its successes, and future directions. As part of this celebration, we invite presentations for this session speculating on the future of computing in geography: potentials, problems, and predictions. What is the future? The Internet of Things? Group cognition modelling? Solar-system scale geomorphological modelling? Speculative discussions encouraged!

Please e-mail the abstract and key words with your expression of intent to Ed Manley (ed.manley@ucl.ac.uk) by 12th February 2016 (one week before the RGS conference deadline).

An abstract should be no more than 250 words.

Organisers:
 – Ed Manley, Centre for Advanced Spatial Analysis (CASA), UCL.
 – Alison Heppenstall, School of Geography, University of Leeds
 – Andrew Evans, School of Geography, University of Leeds
 – Nick Malleson, School of Geography, University of Leeds

ABM and urban economics

New paper just published…

Olner D; Evans A; Heppenstall A (2015) An agent model of urban economics: Digging into emergence, Computers, Environment and Urban Systems, . doi: 10.1016/j.compenvurbsys.2014.12.003

Abstract

Screenshot 2015-10-20 14.09.43This paper presents an agent-based ‘monocentric’ model: assuming only a fixed location for firms, outcomes closely parallel those found in classical urban economic models, but emerge through ‘bottom-up’ interaction in an agent-based model. Agents make buying and movement decisions based on a set of simple costs they face from their current location. These spatial costs are reduced to two types: the costs of moving people and goods across geographical distances and the costs (and benefits) of ‘being here’ (the effects of being at a particular location such as land costs, amenities or disamenities). Two approaches to land cost are compared: landlords and a ‘density cost’ proxy. Emergent equilibrium outcomes are found to depend on the interaction of externalities and time. These findings are produced by looking at how agents react to changing four types of cost, two spatial and two non-spatial: commuting, wage, good cost and good delivery. The models explore equilibrium outcomes, the effect of changing costs and the impact of heterogeneous agents, before focusing in on one example to find the source of emergence in the externalities of agent choice. The paper finishes by emphasising the importance of thinking about emergence as a tool, not an end in itself.