41,422 research outputs found

    Multi-dimensional modelling for the national mapping agency: a discussion of initial ideas, considerations, and challenges

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    The Ordnance Survey, the National Mapping Agency (NMA) for Great Britain, has recently begun to research the possible extension of its 2-dimensional geographic information into a multi-dimensional environment. Such a move creates a number of data creation and storage issues which the NMA must consider. Many of these issues are highly relevant to all NMA’s and their customers alike, and are presented and explored here. This paper offers a discussion of initial considerations which NMA’s face in the creation of multi-dimensional datasets. Such issues include assessing which objects should be mapped in 3 dimensions by a National Mapping Agency, what should be sensibly represented dynamically, and whether resolution of multi-dimensional models should change over space. This paper also offers some preliminary suggestions for the optimal creation method for any future enhanced national height model for the Ordnance Survey. This discussion includes examples of problem areas and issues in both the extraction of 3-D data and in the topological reconstruction of such. 3-D feature extraction is not a new problem. However, the degree of automation which may be achieved and the suitability of current techniques for NMA’s remains a largely unchartered research area, which this research aims to tackle. The issues presented in this paper require immediate research, and if solved adequately would mark a cartographic paradigm shift in the communication of geographic information – and could signify the beginning of the way in which NMA’s both present and interact with their customers in the future

    Spatial interactions in agent-based modeling

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    Agent Based Modeling (ABM) has become a widespread approach to model complex interactions. In this chapter after briefly summarizing some features of ABM the different approaches in modeling spatial interactions are discussed. It is stressed that agents can interact either indirectly through a shared environment and/or directly with each other. In such an approach, higher-order variables such as commodity prices, population dynamics or even institutions, are not exogenously specified but instead are seen as the results of interactions. It is highlighted in the chapter that the understanding of patterns emerging from such spatial interaction between agents is a key problem as much as their description through analytical or simulation means. The chapter reviews different approaches for modeling agents' behavior, taking into account either explicit spatial (lattice based) structures or networks. Some emphasis is placed on recent ABM as applied to the description of the dynamics of the geographical distribution of economic activities, - out of equilibrium. The Eurace@Unibi Model, an agent-based macroeconomic model with spatial structure, is used to illustrate the potential of such an approach for spatial policy analysis.Comment: 26 pages, 5 figures, 105 references; a chapter prepared for the book "Complexity and Geographical Economics - Topics and Tools", P. Commendatore, S.S. Kayam and I. Kubin, Eds. (Springer, in press, 2014

    How about building a transport model of the world?

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    The paper provides a specification, created by the recently completed BLUEPRINT project, for a world transport network model. The model should be able to make predictions (up to 100 years into the future) of transport flows throughout the world and hence make predictions of global climate-changing emissions arising from transport. Furthermore, the model should: cover both passenger and freight traffic; feature all modes of transport (road, rail, non-motorised, water, air and pipeline); and represent both local traffic and long-distance traffic. The paper describes how the model will be structured as the combination of a global model (distinguishing between approximately 30 different geographic regions of the world) and a number of regional and sub-regional models. Wherever feasible, existing regional models will be used in this system, or at least simplified versions of such models. The overall modelling system should be owned jointly by an international network of world transport modellers, welcoming easy entry to other modellers who subscribe to the underlying spirit of the network. The paper recognises the scientific complexities associated with the uncertainties of predicting 100 years into the future and with difficulties arising from the likely differences in modelling philosophy between the (already existing) regional models that might be used in the modelling system. In order to tackle these complexities, the paper defines a number of philosophy of science reference points. At the core of these reference points is the distinction between objectivity and subjectivity. The paper finishes with a number of suggestions for next steps in building the model
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