The latest outputs from researchers, alumni and friends at the UCL Centre for Advanced Spatial Analysis (CASA).
The late Roger Tomlinson is considered the “Father of Geographic Information Systems” and he completed his PhD in the UCL Department of Geography in 1974. Tomlinson pioneered digital mapping – every map created using a computer today still uses the principles he laid down in his thesis and its associated work creating the “The Canada Geographic […]
Continue reading »Deadline 28th July 2017 UCL Department of Geography and the Ordnance Survey are inviting applications for a PhD studentship to explore the internal systematic biases in crowd-sourced geographic information datasets (also known as Volunteered Geographic Information – VGI). The studentship provides an exciting opportunity for a student to work with Ordnance Survey on understanding the … Continue reading PhD studentship in collaboration with the Ordnance Survey – identifying systematic biases in crowdsourced geographic information
The second day of the PPGIS 2017 symposium (see Day 1 here) started with a session on METHODS AND TOOLS. The session opened with a keynote from Peter Nijkamp (Vrije Universiteit Amsterdam, Amsterdam, Netherlands, Adam Mickiewicz University, Poznań, Poland) . The talk is titled “A big data dashboard architecture for computable intelligent city policy“. Peter noted that the … Continue reading PPGIS 2017 – Poznan, Poland (Day 2) – Geodesign, applications and discussion
These notes are from the workshop Modern Methods and Tools for Public Participation in Urban Planning 2017, held in Palac Obrzycko near Poznan, Poland on 22nd and 23rd June 2017 – the outline of the workshop stated “Researchers and practitioners of urban planning have had a variable interest in developing and applying methods of public participation … Continue reading PPGIS 2017 – Poznan, Poland (Day 1) – different notions and tools of public participation GIS
In the recently released “The International Encyclopedia of Geography: People, the Earth, Environment, and Technology” I was asked to write a brief entry on “Cellular Automata“. Below is the abstract to my chapter, along some of the images I used in my discussion, the full reference to the chapter.
Abstract:
Cellular Automata (CA) are a class of models where one can explore how local actions generate global patterns through well specified rules. In such models, decisions are made locally by each cell which are often arranged on a regular lattice and the patterns that emerge, be it urban growth or deforestation are not coordinated centrally but arise from the bottom up. Such patterns emerge through the cell changing its state based on specific transition rules and the states of their surrounding cells. This entry reviews the principles of CA models, provides a background on how CA models have developed, explores a range of applications of where they have been used within the geographical sciences, prior to concluding with future directions for CA modeling.
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| Figure 1: Two-Dimensional Cellular Automata Neighborhoods |
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| Figure 2: Voronoi Tessellations Of Space Where Each Polygon Has A Different Number Of Neighbors Based On A Shared Edge. |
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| Figure 3: Example of Cells Changing State from Dead (White) To Alive (Black) Over Time Depending On The States of its Neighboring Cells. |
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| Figure 4: A One-Dimensional CA Model Implementing “Rule 30” Where Successive Iterations Are Presented Below Each Other. |
Full Reference:
Continue reading »Crooks, A.T. (2017), Cellular Automata, in Richardson, D., Castree, N., Goodchild, M. F., Kobayashi, A. L., Liu, W. and Marston, R. (eds.), The International Encyclopedia of Geography: People, the Earth, Environment, and Technology, Wiley Blackwell. DOI: 10.1002/9781118786352.wbieg0578. (pdf)
In the recently released “The International Encyclopedia of Geography: People, the Earth, Environment, and Technology” I was asked to write a brief entry on “Cellular Automata“. Below is the abstract to my chapter, along some of the images I used in my discussion, the full reference to the chapter.
Abstract:
Cellular Automata (CA) are a class of models where one can explore how local actions generate global patterns through well specified rules. In such models, decisions are made locally by each cell which are often arranged on a regular lattice and the patterns that emerge, be it urban growth or deforestation are not coordinated centrally but arise from the bottom up. Such patterns emerge through the cell changing its state based on specific transition rules and the states of their surrounding cells. This entry reviews the principles of CA models, provides a background on how CA models have developed, explores a range of applications of where they have been used within the geographical sciences, prior to concluding with future directions for CA modeling.
|
| Figure 1: Two-Dimensional Cellular Automata Neighborhoods |
|
| Figure 2: Voronoi Tessellations Of Space Where Each Polygon Has A Different Number Of Neighbors Based On A Shared Edge. |
|
| Figure 3: Example of Cells Changing State from Dead (White) To Alive (Black) Over Time Depending On The States of its Neighboring Cells. |
|
| Figure 4: A One-Dimensional CA Model Implementing “Rule 30” Where Successive Iterations Are Presented Below Each Other. |
Full Reference:
Continue reading »Crooks, A.T. (2017), Cellular Automata, in Richardson, D., Castree, N., Goodchild, M. F., Kobayashi, A. L., Liu, W. and Marston, R. (eds.), The International Encyclopedia of Geography: People, the Earth, Environment, and Technology, Wiley Blackwell. DOI: 10.1002/9781118786352.wbieg0578. (pdf)
Last December, the Natural Environment Research Council (NERC) awarded funding to UCL Extreme Citizen Science group and Earthwatch as part of their investment in public engagement. The projects are all short – they start from January to March and included public engagement and training to early career researchers. “Into the Night” highlights the importance of light … Continue reading Into the night – training day on citizen science slides
It’s always really useful to streamline your workflow, so that the processes can be seamless and efficient. In that regard, I create scenarios for my crowd application that take in Shape files and rasterised GeoTiff files to specify a scenario. The Geo…
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It’s always really useful to streamline your workflow, so that the processes can be seamless and efficient. In that regard, I create scenarios for my crowd application that take in Shape files and rasterised GeoTiff files to specify a scenario. The Geo…
Continue reading »
As part of the AAG 2015 conference, Bandana Kar, Rina Ghose, Renee Sieber and I organised a set of sessions on Public Participation GIS – you can read the summary here. After the conference, we’ve organised a special issue of the Cartographic Journal (thanks to Alex Kent, the journal editor) dedicated to current perspectives of public participation … Continue reading Public Participation GIS and Participatory GIS in the Era of GeoWeb – editorial for a special issue
Part of the special issue on Public Participation GIS that was published in The Cartographic Journal, was a paper that was led by Jeroen Verplanke (ITC). This paper goes back to the workshop on participatory GIS in 2013, that was the leaving event for Dr Mike McCall in ITC, after which he continue to work in UNAM, Mexico. … Continue reading A Shared Perspective for PGIS and VGI – new paper
Results from our analysis show variability in coverage between all these datasets. RCMRD provided the most complete, albeit less current, coverage when taking into account the entire study area, while OSM and Map Maker showed a degradation of coverage as one moves from central Nairobi towards more rural areas. Further information including the abstract to our paper, some figures and full reference is given below.
Abstract:
With volunteered geographic information (VGI) platforms such as OpenStreetMap (OSM) becoming increasingly popular, we are faced with the challenge of assessing the quality of their content, in order to better understand its place relative to the authoritative content of more traditional sources. Until now, studies have focused primarily on developed countries, showing that VGI content can match or even surpass the quality of authoritative sources, with very few studies in developing countries. In this paper we compare the quality of authoritative (data from the Regional Center for Mapping of Resources for Development – RCMRD) and non-authoritative (data from OSM and Google’s Map Maker) road data in conjunction with population data in and around Nairobi, Kenya. Results show variability in coverage between all these datasets. RCMRD provided the most complete, albeit less current, coverage when taking into account the entire study area, while OSM and Map Maker showed a degradation of coverage as one moves from central Nairobi towards rural areas. Furthermore, OSM had higher content density in large slums, surpassing the authoritative datasets at these locations, while Map Maker showed better coverage in rural housing areas. These results suggest a greater need for a more inclusive approach using VGI to supplement gaps in authoritative data in developing nations.Keywords: Volunteered Geographic Information; Crowdsourcing; Road Networks; Population Data; Kenya
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| Road Coverage per km2 |
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| Pairwise difference in road coverage. Clockwise from top left: i) RCMRD 2011 versus Map Maker 2014; ii) RCMRD 2011 versus OSM 2011; iii) RCMRD 2011 versus OSM 2014; iv) OSM 2014 versus Map Maker 2014 (Red cells: first layer has higher coverage; Green cells: second layer has higher coverage). |
Full Reference:
Mahabir, R., Stefanidis, A., Croitoru, A., Crooks, A.T. and Agouris, P. (2017), “Authoritative and Volunteered Geographical Information in a Developing Country: A Comparative Case Study of Road Datasets in Nairobi, Kenya”, ISPRS International Journal of Geo-Information, 6(1): 24, doi:10.3390/ijgi6010024.
As always any thoughts or comments about this work are welcome.
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Results from our analysis show variability in coverage between all these datasets. RCMRD provided the most complete, albeit less current, coverage when taking into account the entire study area, while OSM and Map Maker showed a degradation of coverage as one moves from central Nairobi towards more rural areas. Further information including the abstract to our paper, some figures and full reference is given below.
Abstract:
With volunteered geographic information (VGI) platforms such as OpenStreetMap (OSM) becoming increasingly popular, we are faced with the challenge of assessing the quality of their content, in order to better understand its place relative to the authoritative content of more traditional sources. Until now, studies have focused primarily on developed countries, showing that VGI content can match or even surpass the quality of authoritative sources, with very few studies in developing countries. In this paper we compare the quality of authoritative (data from the Regional Center for Mapping of Resources for Development – RCMRD) and non-authoritative (data from OSM and Google’s Map Maker) road data in conjunction with population data in and around Nairobi, Kenya. Results show variability in coverage between all these datasets. RCMRD provided the most complete, albeit less current, coverage when taking into account the entire study area, while OSM and Map Maker showed a degradation of coverage as one moves from central Nairobi towards rural areas. Furthermore, OSM had higher content density in large slums, surpassing the authoritative datasets at these locations, while Map Maker showed better coverage in rural housing areas. These results suggest a greater need for a more inclusive approach using VGI to supplement gaps in authoritative data in developing nations.Keywords: Volunteered Geographic Information; Crowdsourcing; Road Networks; Population Data; Kenya
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| Road Coverage per km2 |
|
| Pairwise difference in road coverage. Clockwise from top left: i) RCMRD 2011 versus Map Maker 2014; ii) RCMRD 2011 versus OSM 2011; iii) RCMRD 2011 versus OSM 2014; iv) OSM 2014 versus Map Maker 2014 (Red cells: first layer has higher coverage; Green cells: second layer has higher coverage). |
Full Reference:
Mahabir, R., Stefanidis, A., Croitoru, A., Crooks, A.T. and Agouris, P. (2017), “Authoritative and Volunteered Geographical Information in a Developing Country: A Comparative Case Study of Road Datasets in Nairobi, Kenya”, ISPRS International Journal of Geo-Information, 6(1): 24, doi:10.3390/ijgi6010024.
As always any thoughts or comments about this work are welcome.
Continue reading »An aspect of collaborative projects is that they start slowly, and as they become effective and productive, they reached their end! The COST Energic (European Network for Research into Geographic Information Crowdsourcing) led to many useful activities, with some of them leading to academic papers. From COST Energic, we’ve got the European Handbook on Crowdsourced Geographic … Continue reading The Potential of Volunteered Geographic Information (VGI) in Future Transport Systems
Paper Abstract:
Immediately after the 2007 Kenyan election results were announced, the country erupted in protest. Riots were particularly severe in Kibera, an informal settlement located within the nations capital, Nairobi. Through the lens of geosimulation, an agent-based model is integrated with social network analysis and geographic information systems to explore how the environment and local interactions underlying Kibera, combined with an external trigger, such as a rumor, led to the emergence of riots. We ground our model on empirical data of Kibera’s geospatial landscape, heterogeneous population, and daily activities of its residents. In order to effectively construct a model of riots, however, we must have an understanding of human behavior, especially that related to an individual’s need for identity and the role rumors play on a person’s decision to riot. This provided the foundation to develop the agents’ cognitive model, which created a feedback system between the agents’ activities in physical space and interactions in social space. Results showed that youth are more susceptible to rioting. Systematically increasing education and employment opportunities, however, did not have simple linear effects on rioting, or even on quality of life with respect to income and activities. The situation is more complex. By linking agent-based modeling, social network analysis, and geographic information systems we were able to develop a cognitive framework for the agents, better represent human behavior by modeling the interactions that occur over both physical and social space, and capture the nonlinear, reinforcing nature of the emergence and dissolution of riots.
Keywords: agent-based modeling; geographic information systems; social network analysis; riots; social influence; rumor propagation.
Paper Highlights:
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| The high-level UML diagram of the model |
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| A high-level representation of the model’s agent behavior incorporated into the PECS framework |
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| An example of the evolution of social networks of ten Residents across the first two days of a simulation run. |
As with many of our models, we provide the data, model code and detailed model description in the form of the ODD protocol for others to use, learn more or to extend. Click here for more information.
Full Reference:
Pires, B. and Crooks, A.T. (2017), Modeling the Emergence of Riots: A Geosimulation Approach, Computers, Environment and Urban Systems, 61: 66-80. (pdf)
As normal, any thoughts or comments are most appreciated.
Paper Abstract:
Immediately after the 2007 Kenyan election results were announced, the country erupted in protest. Riots were particularly severe in Kibera, an informal settlement located within the nations capital, Nairobi. Through the lens of geosimulation, an agent-based model is integrated with social network analysis and geographic information systems to explore how the environment and local interactions underlying Kibera, combined with an external trigger, such as a rumor, led to the emergence of riots. We ground our model on empirical data of Kibera’s geospatial landscape, heterogeneous population, and daily activities of its residents. In order to effectively construct a model of riots, however, we must have an understanding of human behavior, especially that related to an individual’s need for identity and the role rumors play on a person’s decision to riot. This provided the foundation to develop the agents’ cognitive model, which created a feedback system between the agents’ activities in physical space and interactions in social space. Results showed that youth are more susceptible to rioting. Systematically increasing education and employment opportunities, however, did not have simple linear effects on rioting, or even on quality of life with respect to income and activities. The situation is more complex. By linking agent-based modeling, social network analysis, and geographic information systems we were able to develop a cognitive framework for the agents, better represent human behavior by modeling the interactions that occur over both physical and social space, and capture the nonlinear, reinforcing nature of the emergence and dissolution of riots.
Keywords: agent-based modeling; geographic information systems; social network analysis; riots; social influence; rumor propagation.
Paper Highlights:
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| The high-level UML diagram of the model |
|
| A high-level representation of the model’s agent behavior incorporated into the PECS framework |
|
| An example of the evolution of social networks of ten Residents across the first two days of a simulation run. |
As with many of our models, we provide the data, model code and detailed model description in the form of the ODD protocol for others to use, learn more or to extend. Click here for more information.
Full Reference:
Pires, B. and Crooks, A.T. (2017), Modeling the Emergence of Riots: A Geosimulation Approach, Computers, Environment and Urban Systems, 61: 66-80. (pdf)
As normal, any thoughts or comments are most appreciated.
The bi-annual Geographic Information Science conference is one of the focal point on the field. This year, it was held in Montreal. You can find my talk in a long and separate post. Here are some notes of talks that I took during the meeting. The conference started with reasons for the location, and a … Continue reading GIScience 2016 notes
The GIScience conference is being held every two years since 2000, and it is one of the main conferences in the field of Geographic Information Science (GIScience). It is a special honour to be invited to give a keynote talk, and so I was (naturally) very pleased to get an invitation to deliver such a talk … Continue reading Has GIScience Lost its Interdisciplinary Mojo?
I have had a long fascination with the use of agent-based modeling (ABM) to explore past cultures and civilizations. There are a number of very good models which I will not do justice to in a single post, unless I write a very very long one. Some works…
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I have had a long fascination with the use of agent-based modeling (ABM) to explore past cultures and civilizations. There are a number of very good models which I will not do justice to in a single post, unless I write a very very long one. Some works…
Continue reading »One of the facts about academic funding and outputs (that is, academic publications), is that there isn’t a simple relationship between the amount of funding and the number, size, or quality of outputs. One of the things that I have noticed over the years is that a fairly limited amount (about £4000-£10,000) are disproportionately effective. … Continue reading Patterns of contribution to citizen science biodiversity projects increase understanding of volunteers’ recording behaviour
COST ENERGIC is a network of researchers across Europe (and beyond) that are interested in research crowdsourced geographic information, also known as Volunteered Geographic Information (VGI). The acronym stands for ‘Co-Operation in Science & Technology’ (COST) through ‘European Network Researching Geographic Information Crowdsourcing’ (ENREGIC). I have written about this programme before, through events such as twitter … Continue reading New book: European Handbook of Crowdsourced Geographic Information
The EveryAware book provided an opportunity to communicate the results of a research that Dr Charlene Jennett led, together with two Masters students: Joanne (Jo) Summerfield and Eleonora (Nora) Cognetti, with me as an additional advisor. The research was linked to the EveryAware, since Nora explored the user experience of WideNoise, the citizen science noise monitoring … Continue reading New paper: Usability and interaction dimensions of participatory noise and ecological monitoring
Gianfranco Gliozzo, who is completing his Engineering Doctorate at the Extreme Citizen Science group, written up his first case study and published it in ‘Ecology and Society’. Cited as Gliozzo, G., N. Pettorelli, and M. Haklay. 2016. Using crowdsourced imagery to detect cultural ecosystem services: a case study in South Wales, UK. Ecology and Society … Continue reading New paper: Using crowdsourced imagery to detect cultural ecosystem services: a case study in South Wales, UK
As part of the Esri User Conference, Dawn Wright, Esri Chief Scientist, organised a Science Symposium that gave an opportunity for those with interest in scientific use of Esri GIS to come together, discuss and meet. Dawn Wright opened and mentioned that the science symposium is aimed to bring people people from different areas: … Continue reading Esri User Conference – Science Symposium
During the past spring semester I taught a class entitled “Spatial Agent-based Models of Human-Environment Interactions”. As with many of my courses, students were expected to complete a end of semester project, in this case, develop an agent-based mo…
Continue reading »During the past spring semester I taught a class entitled “Spatial Agent-based Models of Human-Environment Interactions”. As with many of my courses, students were expected to complete a end of semester project, in this case, develop an agent-based mo…
Continue reading »The main Esri User conference starts with a plenary day, where all the participants (16,000 of them) join together for a set of presentation from 8:30 to 3:30 (with some breaks, of course). Below you’ll find some notes that I took during the day: The theme of the keynote was GIS – Enabling a Smarter … Continue reading Esri User Conference 2016 – plenary day
I’ve been working with Geographic Information Systems (GIS) since 1988. During the first 2 years, I wasn’t even aware that what we were doing was GIS – it was a mapping/inventory system that run on second generation PC (80286 processors) and was used to map facilities. Once I’ve discovered that this was a GIS, the … Continue reading Esri Education Conference 2016 – day 1
The slides below are from my keynote talk at the Esri Education User Conference 2016. The conference focused on creativity and its relevant to education and the utilisation of GIS (especially Esri software) at different levels of education. My talk explored the area of citizen science and extreme citizen science and the way geographical technologies … Continue reading Esri Education User Conference talk: Citizen Science & Geographical Technologies: creativity, learning, and engagement
At the forthcoming 2016 International Conference on Social Computing, Behavioral-Cultural Modeling, and Prediction and Behavior Representation in Modeling and Simulation. we will be presenting a paper is entitled “The Geography of Conflict …
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At the forthcoming 2016 International Conference on Social Computing, Behavioral-Cultural Modeling, and Prediction and Behavior Representation in Modeling and Simulation. we will be presenting a paper is entitled “The Geography of Conflict …
Continue reading »One of the joys of academic life is the opportunity to participate in summer schools – you get a group of researchers, from PhD students to experienced professors, to a nice place in the Italian countryside, and for a week the group focuses on a topic – discussing, demonstrating and trying it out. The Vespucci … Continue reading A review of volunteered geographic information quality assessment methods
This past semester I gave a new class at GMU entitled “Urban Analytics”. In a nutshell the class was about introducing students to a broad interdisciplinary field that focuses on the use of data to study cities. More specifcally the emphasis of the cla…
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This past semester I gave a new class at GMU entitled “Urban Analytics”. In a nutshell the class was about introducing students to a broad interdisciplinary field that focuses on the use of data to study cities. More specifcally the emphasis of the cla…
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Several months ago, we posted that we had just had a paper accepted entitled “Walk this Way: Improving Pedestrian Agent-Based Models through Scene Activity Analysis. The original model was created in MASON but know it has been reproduced in NetLogo. Th…
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Several months ago, we posted that we had just had a paper accepted entitled “Walk this Way: Improving Pedestrian Agent-Based Models through Scene Activity Analysis. The original model was created in MASON but know it has been reproduced in NetLogo. Th…
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We recently received word that we had a paper accepted for the upcoming 2016 International Conference on Social Media and Society entitled “Accuracy Of User-Contributed Image Tagging In Flickr: A Natural Disaster Case Study.” In the paper w…
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We recently received word that we had a paper accepted for the upcoming 2016 International Conference on Social Media and Society entitled “Accuracy Of User-Contributed Image Tagging In Flickr: A Natural Disaster Case Study.” In the paper w…
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We recently co-authored a paper entitled “Lessons from the Ebola Outbreak: Action Items for Emerging Infectious Disease Preparedness and Response” in EcoHealth” with several other researchers from George Mason University. In the paper we discuss t…
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