5,497 research outputs found
A dynamic settlement simulation model: Applications to urban growth in Thailand
Evolution at the urban-regional scale reflects complex characteristics in connection with both space and time. An effective way to study urban- regional growth and expansion is to build a hybrid simulation model to represent spatial phenomena at different scales, capable of generating different scenarios in an observable simulated time period. This work reports an implementation of such a simulation model - the Dynamic Settlement Simulation Model (DSSM) - which has been developed based on integrating two different cell-based modelling techniques: cellular automata (CA) and raster GIS. The CA model is used to dynamically simulate the growth of urban cells consistent with a set of probabilistic rules which reflect the system's complexity. The raster GIS module plays the role of controlling mutually static and dynamic constrained spatial variables that significantly affect urban-regional growth. Conceptually, DSSM has been developed using a theory of spatial organisation based on the nodal region from which we need to infer the growth process of urban and regional development over space and time. DSSM has been developed using an object-oriented programming approach the model is composed of all the modules necessary to input the data, visualise the temporal simulation, and yield practical outcomes. For experiments, fabricated data at two different scales has been used to construct the model and explore different growth hypotheses. Furthermore, the model has been applied to two other sets of real data from two major cities in Thailand, Chiang Mai and Phitsanulok city, in order to evaluate its usability and efficiency. The simulation has produced acceptably accurate results when compared quantitatively to the actual land use/cover imagery of both cities. Finally, this work demonstrates how the model can be used as a part of a spatial decision support system (SDSS). It is able to provide other outcomes that represent the possibility of implementing predictive and scenario-based applications, which are applicable to urban and regional planning and related fields
The Repast Simulation/Modelling System for Geospatial Simulation
The use of simulation/modelling systems can simplify the implementation of agent-based models. Repast is one of the few simulation/modelling software systems that supports the integration of geospatial data especially that of vector-based geometries. This paper provides details about Repast specifically an overview, including its different development languages available to develop agent-based models. Before describing Repast’s core functionality and how models can be developed within it, specific emphasis will be placed on its ability to represent dynamics and incorporate geographical information. Once these elements of the system have been covered, a diverse list of Agent-Based Modelling (ABM) applications using Repast will be presented with particular emphasis on spatial applications utilizing Repast, in particular, those that utilize geospatial data
Integrated urban evolutionary modeling
Cellular automata models have proved rather popular as frameworks for simulating the physical growth of cities. Yet their brief history has been marked by a lack of application to real policy contexts, notwithstanding their obvious relevance to topical problems such as urban sprawl. Traditional urban models which emphasize transportation and demography continue to prevail despite their limitations in simulating realistic urban dynamics. To make progress, it is necessary to link CA models to these more traditional forms, focusing on the explicit simulation of the socio-economic attributes of land use activities as well as spatial interaction. There are several ways of tackling this but all are based on integration using various forms of strong and loose coupling which enable generically different models to be connected. Such integration covers many different features of urban simulation from data and software integration to internet operation, from interposing demand with the supply of urban land to enabling growth, location, and distributive mechanisms within such models to be reconciled. Here we will focus on developin
Principles and Concepts of Agent-Based Modelling for Developing Geospatial Simulations
The aim of this paper is to outline fundamental concepts and principles of the Agent-Based Modelling (ABM) paradigm, with particular reference to the development of geospatial simulations. The paper begins with a brief definition of modelling, followed by a classification of model types, and a comment regarding a shift (in certain circumstances) towards modelling systems at the individual-level. In particular, automata approaches (e.g. Cellular Automata, CA, and ABM) have been particularly popular, with ABM moving to the fore. A definition of agents and agent-based models is given; identifying their advantages and disadvantages, especially in relation to geospatial modelling. The potential use of agent-based models is discussed, and how-to instructions for developing an agent-based model are provided. Types of simulation / modelling systems available for ABM are defined, supplemented with criteria to consider before choosing a particular system for a modelling endeavour. Information pertaining to a selection of simulation / modelling systems (Swarm, MASON, Repast, StarLogo, NetLogo, OBEUS, AgentSheets and AnyLogic) is provided, categorised by their licensing policy (open source, shareware / freeware and proprietary systems). The evaluation (i.e. verification, calibration, validation and analysis) of agent-based models and their output is examined, and noteworthy applications are discussed.Geographical Information Systems (GIS) are a particularly useful medium for representing model input and output of a geospatial nature. However, GIS are not well suited to dynamic modelling (e.g. ABM). In particular, problems of representing time and change within GIS are highlighted. Consequently, this paper explores the opportunity of linking (through coupling or integration / embedding) a GIS with a simulation / modelling system purposely built, and therefore better suited to supporting the requirements of ABM. This paper concludes with a synthesis of the discussion that has proceeded. The aim of this paper is to outline fundamental concepts and principles of the Agent-Based Modelling (ABM) paradigm, with particular reference to the development of geospatial simulations. The paper begins with a brief definition of modelling, followed by a classification of model types, and a comment regarding a shift (in certain circumstances) towards modelling systems at the individual-level. In particular, automata approaches (e.g. Cellular Automata, CA, and ABM) have been particularly popular, with ABM moving to the fore. A definition of agents and agent-based models is given; identifying their advantages and disadvantages, especially in relation to geospatial modelling. The potential use of agent-based models is discussed, and how-to instructions for developing an agent-based model are provided. Types of simulation / modelling systems available for ABM are defined, supplemented with criteria to consider before choosing a particular system for a modelling endeavour. Information pertaining to a selection of simulation / modelling systems (Swarm, MASON, Repast, StarLogo, NetLogo, OBEUS, AgentSheets and AnyLogic) is provided, categorised by their licensing policy (open source, shareware / freeware and proprietary systems). The evaluation (i.e. verification, calibration, validation and analysis) of agent-based models and their output is examined, and noteworthy applications are discussed.Geographical Information Systems (GIS) are a particularly useful medium for representing model input and output of a geospatial nature. However, GIS are not well suited to dynamic modelling (e.g. ABM). In particular, problems of representing time and change within GIS are highlighted. Consequently, this paper explores the opportunity of linking (through coupling or integration / embedding) a GIS with a simulation / modelling system purposely built, and therefore better suited to supporting the requirements of ABM. This paper concludes with a synthesis of the discussion that has proceeded
An open and extensible framework for spatially explicit land use change modelling in R: the lulccR package (0.1.0)
Land use change has important consequences for biodiversity and the
sustainability of ecosystem services, as well as for global
environmental change. Spatially explicit land use change models
improve our understanding of the processes driving change and make
predictions about the quantity and location of future and past
change. Here we present the lulccR package, an object-oriented
framework for land use change modelling written in the R programming
language. The contribution of the work is to resolve the following
limitations associated with the current land use change modelling
paradigm: (1) the source code for model implementations is
frequently unavailable, severely compromising the reproducibility of
scientific results and making it impossible for members of the
community to improve or adapt models for their own purposes; (2)
ensemble experiments to capture model structural uncertainty are
difficult because of fundamental differences between implementations
of different models; (3) different aspects of the modelling
procedure must be performed in different environments because
existing applications usually only perform the spatial allocation of
change. The package includes a stochastic ordered allocation
procedure as well as an implementation of the widely used CLUE-S
algorithm. We demonstrate its functionality by simulating land use
change at the Plum Island Ecosystems site, using a dataset included
with the package. It is envisaged that lulccR will enable future
model development and comparison within an open environment
Multi-agent simulation: new approaches to exploring space-time dynamics in GIS
As part of the long term quest to develop more disaggregate, temporally dynamic models of spatial behaviour, micro-simulation has evolved to the point where the actions of many individuals can be computed. These multi-agent systems/simulation(MAS) models are a consequence of much better micro data, more powerful and user-friendly computer environments often based on parallel processing, and the generally recognised need in spatial science for modelling temporal process. In this paper, we develop a series of multi-agent models which operate in cellular space.These demonstrate the well-known principle that local action can give rise to global pattern but also how such pattern emerges as the consequence of positive feedback and learned behaviour. We first summarise the way cellular representation is important in adding new process functionality to GIS, and the way this is effected through ideas from cellular automata (CA) modelling. We then outline the key ideas of multi-agent simulation and this sets the scene for three applications to problems involving the use of agents to explore geographic space. We first illustrate how agents can be programmed to search route networks, finding shortest routes in adhoc as well as structured ways equivalent to the operation of the Bellman-Dijkstra algorithm. We then demonstrate how the agent-based approach can be used to simulate the dynamics of water flow, implying that such models can be used to effectively model the evolution of river systems. Finally we show how agents can detect the geometric properties of space, generating powerful results that are notpossible using conventional geometry, and we illustrate these ideas by computing the visual fields or isovists associated with different viewpoints within the Tate Gallery.Our forays into MAS are all based on developing reactive agent models with minimal interaction and we conclude with suggestions for how these models might incorporate cognition, planning, and stronger positive feedbacks between agents
GeoComputational Intelligence and High-Performance Geospatial Computing
Assistant Professor, School of Natural Resources. Center for Advanced Land Management Information Technologies, University of Nebraska – LincolnPlatinum Sponsors
Coca-Cola
Gold Sponsors
KU Department of Geography
KU Institute for Policy & Social Research
KU Libraries GIS and Data Services
State of Kansas Data Access and Support Center (DASC)
Wilson & Company Engineers and Architects
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Bartlett & West
Kansas Applied Remote Sensing Program
KansasView
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Garmin
KU Biodiversity Institut
Urban land use change analysis and modelling: a case study of Setubal-Sesimbra, Portugal
Dissertation submitted in partial fulfilment of the requirements for the Degree of Master of Science in Geospatial TechnologiesIn this paper urban land use change analysis and modeling of the Concelhos of
SetĂşbal and Sesimbra, Portugal is accomplished using multitemporal and
multispectral satellite images acquired in the years 2000 and 2006 and other vector
datasets. The LULC maps are first obtained using an object-oriented image
classification approach with the Nearest Neighbour algorithm in Definiens.
Classification is assessed using the overall accuracy and Kappa measure of
agreement. These measures of accuracies are above minimum standard accepted
levels. The land use dynamics, both for pattern and quantities are also studied using a post classification change detection technique together with the following selected spatial/landscape metrics: class area, number of patches, edge density, largest patch index, Euclidian mean nearest neighbor distance, area weighted mean patch fractal
dimension and contagion. Urban sprawl has also been measured using Shannon
Entropy approach to describe the dispersion of land development or sprawl. Results
indicated that the study area has undergone a tremendous change in urban growth
and pattern during the study period. A Cellular Automata Markov (CA_Markov)
modeling approach has also been applied to predict urban land use change between
1990 and 2010 with two scenarios: MMU 1ha and MMU 25ha. The suitability maps
(change drivers) are calibrated with the LULC maps of 1990 and 2000 using MCE
and a contiguity filter. The maps of 1990 and 2000 are also used for the transition
probability matrix. Then, the land use maps of 2006 are simulated to compare the
result of the “prediction” with the actual land use map in that year so that further
prediction can be carried out for the year 2010. This is evaluated based on the Kappa
measure of agreement (Kno, Klocation and Kquanity) and produced a satisfactory
level of accuracy. After calibrating the model and assessing its validity, a “real”
prediction for the year 2010 is carried out. Analysis of the prediction revealed that
the rate of urban growth tends to continue and would threaten large areas that are
currently reserved for forest cover, farming lands and natural parks. Finally, the
modeling output provides a building block for successive urban planning, for
exploring how an
Geospatial Data Management Research: Progress and Future Directions
Without geospatial data management, today´s challenges in big data applications such as earth observation, geographic information system/building information modeling (GIS/BIM) integration, and 3D/4D city planning cannot be solved. Furthermore, geospatial data management plays a connecting role between data acquisition, data modelling, data visualization, and data analysis. It enables the continuous availability of geospatial data and the replicability of geospatial data analysis. In the first part of this article, five milestones of geospatial data management research are presented that were achieved during the last decade. The first one reflects advancements in BIM/GIS integration at data, process, and application levels. The second milestone presents theoretical progress by introducing topology as a key concept of geospatial data management. In the third milestone, 3D/4D geospatial data management is described as a key concept for city modelling, including subsurface models. Progress in modelling and visualization of massive geospatial features on web platforms is the fourth milestone which includes discrete global grid systems as an alternative geospatial reference framework. The intensive use of geosensor data sources is the fifth milestone which opens the way to parallel data storage platforms supporting data analysis on geosensors. In the second part of this article, five future directions of geospatial data management research are presented that have the potential to become key research fields of geospatial data management in the next decade. Geo-data science will have the task to extract knowledge from unstructured and structured geospatial data and to bridge the gap between modern information technology concepts and the geo-related sciences. Topology is presented as a powerful and general concept to analyze GIS and BIM data structures and spatial relations that will be of great importance in emerging applications such as smart cities and digital twins. Data-streaming libraries and “in-situ” geo-computing on objects executed directly on the sensors will revolutionize geo-information science and bridge geo-computing with geospatial data management. Advanced geospatial data visualization on web platforms will enable the representation of dynamically changing geospatial features or moving objects’ trajectories. Finally, geospatial data management will support big geospatial data analysis, and graph databases are expected to experience a revival on top of parallel and distributed data stores supporting big geospatial data analysis
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