Rainfall Model: NetLogo

Now whats seems like a long time ago, we where inspired to by  the NetLogo Grand Canyon Model and created a similar model in GeoMason. Now we have returned to NetLogo to test its ability to handle GIS data. Below you can see our attempt. The model is based on importing a geotiff of the National Elevation Dataset at 1 arc second from the National Map of Crater Lake, Oregon. After which water is added (which could be considered loosely as agents) and flows from high to low elevations, if the water cannot flow over the surface, it pools up.

The first movie below acts as a verification exercise about the basic functioning of the model (i.e. did we build the model right?). Here we have three different map types. The first being flat, the second being a cone and the third being a hill. The idea with these map types is to ensure the basic functioning of the model is correct.

After we were happy with the model, the Crater Lake example was implemented. As the movie below shows, over time, Crater Lake slowly fills up until the water breaches the caldera rim which allows the water to flow out. An extra addition to the model is the addition of erosion. Whereby as water flows over the surface, it picks up some sediment (in this case 1 unit of elevation) and when it stops moving, it deposits the sediment. As a result the terrain in the area changes. 

While carrying out this exercise, we also thought about testing NetLogo's 3D capacity with respect to creating geographically explicit agent-based models. The movie below shows the results.

More information about the models in this post can been seen on Yang Zhou's website. Also the models can be downloaded from GitHub. We hope you enjoy.

A Semester with OpenSim

Over the last few months I have been teaching a class in the Department of Computational Social Science entitled "Building Virtual Worlds" where we surveyed the role of virtual worlds for social science research. The emphasis of the class was on tools, software frameworks, and applications of virtual worlds.  On the applications side we discussed how virtual worlds are being used for History, Archeology, Healthcare, Tourism, Urban Modeling, Architecture, Agent-based Modeling along with more generally teaching and learning. We explored a variety of tools for building virtual worlds before focusing on OpenSim. The movie below shows some of the final outputs using OpenSim.

We used OpenSim 0.7.3, configured with the Standalone-Hypergrid mode and a SQLite database hosted on a Windows 7 server. The server simultaneously simulated 64 different regions, and at various points during the semester the server hosted well over 15000 primitives (prims) and ran hundreds of scripts across this landscape; one region alone hosted over 8000 prims. 

Why so many regions? We were interested in how many the server could cope with but also we wanted to have a virtual world representing the whole of the GMU Fairfax campus  (~4km²) and regions in OpenSim are limited to 256m by 256m. We built the terrain for the campus utilizing the National Elevation Dataset (NED) DEM from the United States Geological Survey which was first manipulated in ArcGIS before being processed in  L3DT (Large 3D Terrain Generator). Finally, the DEM was imported into OpenSim. The movie below should give a sense of what the basic terrain looks like.

Once the terrain was built, we populated it with buildings, however, we were not just interested in the external appearance of the buildings but also there internal structure for modeling and simulation purposes.  Therefore the class focused their attention on building a highly detailed Johnson Center.

Model of Johnson Center taken from Google SketchUp 3D Warehouse

Vector based, 2D CAD files were obtained and imported into Google SketchUp before using SketchLife to build the 3D initial building core, walls, doors and windows.

Constructing a vector-based model of the Johnson Center internal structure

The SketchLife final rendering of the Johnson Center

Once built in SketchUp using SketchLife the model was imported into OpenSim 

External view “in world” of what we accomplished in building the Johnson Center

In addition to using SketchLife for the JC, many objects such as chairs, staircases and tables were either built using the tool or those native to OpenSim.

An “in world” shot at ground level, on the 1st floor, viewing the atrium and clock tower
 in the Johnson Center

CSS class photo "in-world"

However, our work with OpenSim does not stop here, below is another movie of some ongoing work with one of our PhD students, Chris Rouly who is creating agent-based models embedded in OpenSim to explore past habitats among many other things.

I would like to thank the "Building Virtual Worlds" class and the Department for enabling this blog post.

Project Geppetto

Project Geppetto from Autodesk attempts to make it it easy, fast, and fun to add crowds to 3ds Max scenes. It is part of Autodesk's  "People Power" concept, where the basic idea is to try to assemble all the components one needs to create, manage, and control large crowds of characters. Specificcally it attempts to create believable motion, allow for cultural influences (Evolver) and to create a framework for thousands of characters to interact in. Below are some examples of the project.

Avatars in OpenSim

OpenSim (OpenSimulator) "is a 3D Application Server. It can be used to create a virtual environment (or world) which can be accessed through a variety of clients, on multiple protocols." In a sense its similar to Second Life (SL) but one can host environment on ones own web server (Click here to see some of ourt previous work with SL).

One of the problems with using SL is that one has to own/rent the land in which the environment is created and housed. While with OpenSim one only needs a web server which in a sense is highly appealing for creating permanent environments. Another problem we encountered when using SL was the time it took to execute our agent-based models due to the SL servers. So when I was shown by Chris Rouly this latest test on the ScienceSim Beta Grid by Nebadon Izumi showing 1000 Avatars of mostly bots but some human controlled avatars in real time (as shown below), this got me thinking again about agent-based modeling in virtual worlds.

It would be nice to see Avatars (agents) populating real buildings such as the Ajax FC stadium below. Where the agents are programed to react to changing conditions such as evacuation in times of crisis.

The Ajax FC stadium (Source: KZero Worldswide)

One of our initial tests on using SL for the evacuation of buildings can be seen below. But in our example we only use a maximum of 100 agents but using 1000s of agents with real anthropomorphic dimensions in a 3D space and in real time is highly appealing.

GMU Fiarfax Campus created with CityScape

I have just been exploring the demo version of CityScape from PixelActive and I am quite impressed. CityScape is an urban modeling tool that allows users to build both custom and real-world environments quickly and easily. The focus of the modeler is on allowing developers to concentrate on design rather than the labor involved in creation.

The movie below show my initial attempt of creating a agent-based traffic model around the Fairfax Campus of George Mason University. The model utilizes a real world elevation data downloaded from the U.S. Geological Survey's (USGS) National Map, the road data comes from OpenStreetMap and the building footprints from the Geospatial Data Collection at Mason.

Some readers might find the movie below from an earlier post created in Repast Simphony an interesting comparison. Basically in this model, agents are pedestrians and they choose the shortest route between two buildings.

New Paper: Agent Street: An Environment for Exploring Agent-Based Models in Second Life

Our work with agent-based modeling in Second Life has just been published in the Journal of Artificial Societies and Social Simulation (JASSS). The full title of the paper is "Agent Street: An Environment for Exploring Agent-Based Models in Second Life" and the abstract reads as follows:

"Urban models can be seen on a continuum between iconic and symbolic. Generally speaking, iconic models are physical versions of the real world at some scaled down representation, while symbolic models represent the system in terms of the way they function replacing the physical or material system by some logical and/or mathematical formulae. Traditionally iconic and symbolic models were distinct classes of model but due to the rise of digital computing the distinction between the two is becoming blurred, with symbolic models being embedded into iconic models. However, such models tend to be single user. This paper demonstrates how 3D symbolic models in the form of agent-based simulations can be embedded into iconic models using the multi-user virtual world of Second Life. Furthermore, the paper demonstrates Second Life's potential for social science simulation. To demonstrate this, we first introduce Second Life and provide two exemplar models; Conway's Game of Life, and Schelling's Segregation Model which highlight how symbolic models can be viewed in an iconic environment. We then present a simple pedestrian evacuation model which merges the iconic and symbolic together and extends the model to directly incorporate avatars and agents in the same environment illustrating how 'real' participants can influence simulation outcomes. Such examples demonstrate the potential for creating highly visual, immersive, interactive agent-based models for social scientists in multi-user real time virtual worlds. The paper concludes with some final comments on problems with representing models in current virtual worlds and future avenues of research."

Agents reacting to Avatars

Accompanying the paper we have created a dedicated website giving more details about the work including the model source code which can be found here.

Our next steps are to start exploring how such models can be created and extended in OpenSim and carrying out user testing along with online model creation.

The full reference to the paper is:

Crooks, A, Hudson-Smith, A and Dearden, J (2009). 'Agent Street: An Environment for Exploring Agent-Based Models in Second Life'. Journal of Artificial Societies and Social Simulation, 12(4)10: http://jasss.soc.surrey.ac.uk/12/4/10.html.

Modelling large crowds

The last few days I been reading up on pedestrian models, 3D cityscapes and the simulation of large crowds. One such paper that caught my eye was by Treuille et al. (2006) entitled Continuum Crowds. The abstract of the paper is:

"We present a real-time crowd model based on continuum dynamics. In our model, a dynamic potential field simultaneously integrates global navigation with moving obstacles such as other people, efficiently solving for the motion of large crowds without the need for explicit collision avoidance. Simulations created with our system run at interactive rates, demonstrate smooth flow under a variety of conditions, and naturally exhibit emergent phenomena that have been observed in real crowds."

The movie below shows their work:

Reference

Treuille, A., Cooper, S. and Popovic, Z. (2006), 'Continuum Crowds', in Dorsey, J. (ed.), Proceedings of ACM SIGGRAPH 2006 ACM, Boston, MA, pp. 1160-1168

Where 2.0 Conference Talks

The presentations from the Where 2.0 conference always blow me away. I just been looking at some, and three in particular caught my attention. The first was Jack Dangermond's "Realizing spatial intelligence on the GeoWeb" The idea behind the talk was that geographic knowledge created in GIS environments is increasingly being made available to Web 2.0 users.

Other interesting talks with regard to building city models and understanding cities was Ludvig Emgård "World's Most Realistic 3D City Models?" and John Geraci's "DIY City: An Operating System for Cities."

World's Most Realistic 3D City Models?

DIY City: An Operating System for Cities

Useful Link:
GIS and Science blog

NetLogo to 3D Max

I am a great fan of NetLogo for the development of agent-based models. At CASA we have been exploring how one can loosely couple NetLogo models with 3D Max. The reason being that 3D Max offers a means of visualization which is beyond NetLogo's for example, building 3D city scapes.

Ateen Patel a PhD student at CASA and author of the Crowd Simulation Blog has written a short tutorial (including the code) and several other posts on how to get information from a simple NetLogo Traffic Model and to visualize the model in 3D Max.

Such outputs can be seen in the movie below from Digital Urban:

The Crowd Simulation Blog is worth keeping an eye on for those interested in pedestrian modeling as Ateen's research and his blog explores new methods for rendering very large crowd scenes that contain the correct kinds of physics and dynamics that enable realistic simulations to be generated.

Update: Agent-based models in Second Life

We just finished another part of Agent-Street where agents and avatars can interact with each other. The idea here is to merge iconic and symbolic urban models in a multi-user real time environment.

The movie below shows Agent-Street and how one can download the models we have created by clicking on the model vending machines. By clicking on the vending machines, models can be downloaded and saved. Such vending machines are common features in Second Life and allow users to store objects and scripts in their personal inventory for later use such as rebuilding the models on their own Land or in free sand-boxes. We have been using the Mauve Land for this (SLURL).

In our previous models avatars could only visualise and initiate the models. For example, in the pedestrian evacuation model users could only observe how agents exited the building (in a similar way to professionally developed 3D pedestrian modelling software packages such as STEPS). In this new model, we extend the basic pedestrian evacuation model, so that agents not only consider their environments but also other avatars. In this sense we are not only incorporating iconic and symbolic modelling styles but also adding a further human dimension, moving towards an augmented reality (i.e. as if the agents and the humans were in the same crowd). The movie below shows how pedestrian paths change when avoiding an avatar. The movie shows a how an avatar stationed near the exit impacts on pedestrian egress as agents have to move around it.

Previous posts on our and others work on Second Life can be found by clicking here. We have also set up a website outlining the work in detail (click here) or alternatively if you have a Second Life account this SLurl will take you to the Land, once you teleport to the area, follow the red arrow (beam of red light) into the sky to find Agent-Street. If the models are running slow let us know as we having problems with fish entering our land from a neighbouring island.

Pedestrian modelling of Oxford Circus redesign

Oxford Circus in London is a busy intersection between Regent Street and Oxford Street with more than 200m visitors a year (BBC). Work is to begin on a £5m project to pedestrianise part of Oxford Circus. Based on crossings in Tokyo, the new design will stop all traffic in all directions, and allow people to cross diagonally as well as straight ahead. Street clutter and barriers at the junction of Oxford Street and Regent Street will also be removed.

Graphic showing the Oxford Circus redesign

Why blog about this? The movie below created by Designhive shows how Atkins' two-dimensional traffic and pedestrian models can be coupled with 3D Studio Max in such a way it is difficult to distinguish the model from a real piece of video footage. Combining the models in the simulation in this way makes the finished product particularly compelling. Furthermore it has the benefit of being based on the technical models developed to test the proposals prior to their implementation (such as the removal of street clutter).

The pedestrian model is a particle-based system controlling 5000 agents to match up the data produced by Atkins Intelligent Space. When the final simulation was rendered, the 'particles' were replaced with animated people, programmed to walk while the points were moving and idle when the points stopped for traffic lights.

Thanks to Duncan Smith for flagging this. Further information:

• Intelligent Space
• designhive
• BBC News Item: Oxford Circus crossing redesigned
• Building Design website news item
  
  

Work update

Currently at CASA we are exploring ways to simulate various aspects of city life and visualize such models taking advantage of our London database which we are developing along with the advances in graphic card technology and networked communication. We presented some of this work at the AAG last week (click here to download the presentation and here to see the abstract).

Some of this includes modeling traffic. Following on from an earlier post by Andrew-Hudson Smith of Digital Urban about CityScape, the movie below shows our first attempts with the software.

New Developments in GIS for Urban Planning

We just finished writing a brief paper for the April 2009 issue of Geospatial Today entitled "New Developments in GIS for Urban Planning". The paper basically covers new the tools and techniques being developed at CASA which we are targeting at urban planners. Many of the tools are associated with visualising urban problems and their solutions.

Virtual London within Google Earth

Full Reference:

Batty, M., Hudson-Smith, A., Crooks, A. T., Milton R. and Smith D. (2009) New Developments in GIS for Urban Planning, Geospatial Today, June: 40-43. (pdf).

AAG Agent Talk

Next week, I will be attending the AAG annual meeting in Las Vegas, which I am quite looking forward to. There seems to be a good selection of agent-based modelling talks along with others relating to GIS, urban planning etc. I will be presenting a paper with Andrew Hudson-Smith in the Modeling Geographic Complexity 2 session entitled "Agents in the City: Modeling and Visualizing Emergent Phenomena."

The abstract for the talk is:

Agent-based modeling (ABM) is increasingly being used as a tool for the spatial simulation of a wide variety of urban phenomena. As ABM moves into the spatial domain, we need new ways to visualize and communicate such models especially to those who we seek to influence and who we believe that such modeling will inform their activities. Coupled with the above challenge is how we represent agents in space. The use of ABM for geospatial simulation has traditionally been dominated by the 2D view of the world with the third dimension rarely ventured into. We would argue that this is due to the nature of the discipline where the focus is on theory rather than outreach and end user visualization; and that model builders are not taking advantage in improvements in computer technology. We will illustrate our attempts to visualize, share and communicate geospatial agent-based models specifically focusing on the third dimension with several examples utilizing 3D Studio Max and Second Life, a virtual online world. These examples range through the movement of cars and pedestrians in a cityscape to evacuation of pedestrians from buildings and residential segregation. These models demonstrate how through the interaction of individual agents complex phenomena emerges over time and in space. Furthermore they demonstrate how different theories and concepts can be incorporated into 3D environments. Additionally these models provide outputs to which non-expert users can easily relate to, thus allowing them to come under greater scrutiny than was possible in the past.

Agents in the City: building cityscapes

Hope to see you there.

Agent-based models for Venice

While reading the Venice 2.0 blog by Fabio Carrera which explores research projects in Venice, Italy, I came across two interesting agent-based models, the first is simulating Venetian boat traffic for city officials (click here to see a movie). The second model is the the evacuation of Saint Mark's square both models were co-created with the Redfish Group (Click here to see an earlier post on the work of Redfish).

Further information about the work can be seen on the SantVe site.

Simulating boat traffic in Venice (using NetLogo, Source SantaVe)

Simulation of pedestrian traffic through a square in Venice by Fabio Carrera. Source Venice 2.0.

Urban Informatics

Cities provide habitats for over half the worlds population and this is expected to increase to 70% by 2050 (United Nations, 2007). Coinciding with this growth is the increasing use of information communication technologies (ICTs) such as mobile phones, wireless networks, Global Positioning Systems (GPS), and web based services in our personal and professional activities. Such technology is changing our daily lives, not only in the way we communicate and interact with each other or share information but also how we view the city.

Urban informatics research has evolved to explore this change. It is concerned with the impact of technology, systems and infrastructure on people in urban the environment. It draws researchers together from a broad spectrum of academic communities. For example, the social (media studies, cultural studies etc.) the urban (urban studies, urban planning, etc.) and the technical (computer science, software design human-computer interaction etc.) and focuses attention on the opportunities and problems of such ubiquitous computing.

Marcus Foth in this edited book entitled “Handbook of Research on Urban Informatics: The Practice and Promise of the Real-Time City” brings together in 29 chapters on recent research and development in the field of urban informatics from around the world. The book covers a plethora of topics including; community engagement, digital cities, digital identities, locative media, mobile and wireless applications, participatory planning, personal privacy, surveillance and sustainability.

The book is spilt into six parts, the first part introduces urban informatics and highlights it diverse application areas, including how people are adapting to such digital technologies and how they are impacting on urban dynamics. Section two explores who is participating and how ICTs are being used. Questions addressed include why people join online communities, its use for community planning, how such technologies can trigger or sustain civic participation or how ICTs can be used in public spaces for collective expression through large screen interactive projections.

The third section explores how one can engage urban communities through the use of ICTs and enable the communication of information and interaction between people in the city. For example, location based media accessed through GPS enabled devices. Section four discusses how ICTs can impact on location, navigation and space such as studying online social networks along-side their real world counterparts. How augmented maps can aid car navigation or how virtual cities can be used as a test-bed for examining the design of urban public spaces through the use of agent-based modelling. Section five discusses the development of wireless and the mobile cultures and how such technologies impact on our daily lives and activities both at home and in the city including the development of community wireless networks and how mobile phone use in urban cultures are reducing the need for premade plans.

The final section explores how ubiquitous and pervasive computing might develop and be used in the future, not only how it can advance urban functions but also its potential problems. For example, the increasing deployment of sensors and electronic devices within the transport network will allow for real time access to route planning thus avoiding congested areas. For the citizen of a city, the development of ICTs will encourage greater mobility for or be used to coordinate social action such as protests (see Justo, 2004). ICTs could also be used as a tool for collective problem solving but such technology will also challenge existing social structures and potentially distance people from more traditional face to face contact.

In summary, the book pulls together a diverse literature of ICTs, how they are used throughout the world. The chapters range from critical reflections on who is using the technology and how, to more technical applications. The chapters are mostly well written and referenced. Each chapter has a key terms section which is extremely useful in understanding each chapter. The chapters are mostly well written. My only criticisms of the book are the quality of the images (they are all black and white) while some of the text refers to them in colour and the cost at $265. Nevertheless, it does provide a useful resource for social and computer scientists.

In relation to my own research, I am interested in how such technologies can be utilised for the creation of agent-based models and thus providing a greater understanding of cities and their inhabitants.

References

Justo, P D, 2004, Protests Powered by Cellphone, The New York Times (September 9th).

United Nations, 2007, World Urbanization Prospects: The 2007 Revision, Department of Economic and Social Affairs: Population Division, New York, NY.

Work update

Sorry for the lack of posts recently, we have been working on a number of projects. One is creating a simplified road network for London to explore the road structure in relation to network theory (see Masucci) but also for its use in accessibility measures. Our second project is building a detailed land use database for London (using SQL Server which we access through ArcSDE).

The purpose of the database is so our research group can use it for various applications (such as land use modelling, residential agent-based modelling, urban sprawl analysis, sustainability, rain water harvesting etc). The aim of the land use database is to tag all the buildings within London with various attributes such as use, whether it is a house, a flat or an office etc. The data sets we are using include; Ordnance Survey MasterMap and Address layer 2 , building heights via LIDAR data from InfoTerra. We are using Cities Revealed data for residential building types and age along with several other datasets. When combined it will allow for fine scale and extensive modelling of the of London’s housing market & built environment.

Below are some preliminary outputs, including a land use visualisation of the Isle of Dogs, the London Borough of Tower Hamlets broken down by residential property types and finally residential density within a section of the Isle of Dogs.

Isle of Dogs Land-use 3D Visualisation (Red is Residential, Dark blue is Office, Light blue is Office Mixed Use).

Housing Classification of Tower Hamlets, London (yellow is terraced housing, blue is flats and grey is non residential).

Residential Density within the Isle of Dogs (Dwellings per Hectare)

Agent-based models for Latin American Cities

Latin American cities are characterised by high speeds of urban growth and the development of spontaneous settlements. Such change has produced many problems especially in relation to urbanisation and housing.

The other day I came across the work of Guilherme Ressul who maintains the tzero site. One of his projects is to model the growth and development of Favelas in Brazil. For the project he has created an agent-based model using Maya to explore the growth of such developments. If you are interested in such 3D visualisation and agent-based modelling it is worth exploring his Favela micro-site, which includes movies, scripts and further information about the project.

Another interesting agent-based model specifically developed for the study of Latin American cities, in relation to urban growth is that by Joana Barros. Her model focuses on a specific kind of urban growth that happens in Latin American cities, called “peripherisation”. This is characterised by the formation of low income residential areas in the peripheral ring of the city.

More information on Joana's work can be found here.

Virtual cities for simulating movment in public spaces

While reading Urban Informatics (Foth, 2009) I came across an interesting article by Nakanishi et al. (2009) entitled “Virtual Cities for Simulating Smart Urban Public Spaces” which explores the use of virtual cities as a test bed for examining the design of urban public spaces. Specifically the authors combine an agent-based model with a virtual city model (in this case a platform at the Kyoto subway station) and used augmented reality to allow humans to interact with the agents (as if the agents and the humans where in the same crowd) through the use of positioning sensors around the station and then simulated an emergency.

Further information about the project, including the software Freewalk where humans and agents can socially interact with one another in a virtual city space can be found here.

References:

Foth, M. (2009), Handbook of Research on Urban Informatics: The Practice and Promise of the Real-Time City, IGI Global, Hershey, PA.

Nakanishi, H., Ishida, T. and Koizumi, S. (2009), 'Virtual Cities for Simulating Smart Urban Public Spaces', in Foth, M. (ed.) Handbook of Research on Urban Informatics: The Practice and Promise of the Real-Time City, IGI Global, Hershey, PA, pp. 257-269.

CASA S4 Modelling Tour Workshop

Last week CASA hosted a two day workshop showcasing our work along with researchers from the University of Leeds as part of the of the S4 European Spatial Analysis network modelling tour. Over 150 people both from the public and private sector came to the event from all across Europe. The first day of the event was designed to showcase CASA's use of new technologies for mapping and visualizing information about cities and was entitled "Geographic Information in a Web-Based World."

Talks ranged from introducing GMapCreator and MapTube which enable web-based mapping for sharing and visualising geographic information, to public engagement via the London Profiler, Public Profiler and the E-Society Classification websites. The geography and ethnicity of people's names was explored which introduced the WorldNames and Onomap websites.

Other talks on the first day explored the use of MapTube and GMapCreator for Crowdsourcing near-real time spatial surveys and understanding crowdsourced geographical information via the analysis of OpenStreetMap. On a more data oriented side, there were talks on exploring urban data collection and mapping, analysing and visualising fine scale urban form and socio-economic datasets. The day concluded with a talk by Andrew Hudson-Smith from Digital Urban on Web 2.0 and neogeography in real and virtual spaces: from geocaching through to Second Life.

The second day of the workshop was entitled "Developments in Urban Models, Simulation and Spatial Analysis" and talks ranged from: rank clocks and scaling in city sizes, geodemographics, retail modelling, the need to capture urban form patterns and processes in agent-based models, pedestrian modelling, consumer behaviour, microsimulation and 3D visualisation and communication of agent-based models.

Click here to see the full program and to download the presentations.