Geoexpression : A Petri network framework for representing geographic process concurrency

2018 ◽  
Vol 22 (6) ◽  
pp. 1390-1405
Author(s):  
Austin V. Davis ◽  
Shaowen Wang
Keyword(s):  
2019 ◽  
Vol 8 (9) ◽  
pp. 408
Author(s):  
Song ◽  
Niu ◽  
Li

Building fire is a complex geographic process related to the indoor spatial environment, a smart spatial data model can accurately describe the spatial-temporal information of a building fire scene, which is important for modeling a fire process. With the development of fire dynamics and computer science, many building fire models have been proposed and widely used. However, the spatial representation of these models is relatively weak. In this study, a fire process modeled via the Fire Dynamics Simulator (FDS) and the requirements of a spatial data model are initially analyzed. Then, a new spatial data model named the Combinatorial Spatial Data Model (CSDM) is combined with Geographic Information System (GIS). The key features of the CSDM, which include spatial, semantic, topological, event and state representations of a building fire scene modeled via the CSDM are subsequently presented. In addition, the Unified Modeling Language (UML) class diagram of the CSDM is also presented, and then experiments with a simplified building are conducted as a CSDM implementation case. A method of transferring data from the CSDM to FDS and a building fire analysis approach using the CSDM are subsequently proposed.


2013 ◽  
Vol 307 ◽  
pp. 464-469
Author(s):  
Bing Chuan Jiang ◽  
Xiong You ◽  
Qing Xia ◽  
Wei Zhang

The expression of virtual geographic environment is based on the surface modeling, such as three-dimensional terrain modeling and rendering most of which are based on the polygon grid and 2D textured. In the expression of extreme terrain, such as caves, cliffs, canyons it seems powerless. However, the voxel-based terrain modeling has been more useful than polygon modeling expression in the field of real-time terrain deformation, extreme terrain simulation and geographic process expression. Furthermore, virtual geographic environment based on the traditional surface model is difficult to realistically simulate the real world which is volumetric. This paper analyzes the trends of the geographical environment representation, and discusses the typical voxel-based applications in natural phenomena simulation, terrain modeling and spatial process analysis. It provides the references for the integrative representation of the unified voxel and surface model, and for the construction of virtual geographic environment unified platform.


2019 ◽  
Vol 8 (12) ◽  
pp. 566
Author(s):  
Yi Huang ◽  
May Yuan ◽  
Yehua Sheng ◽  
Xiangqiang Min ◽  
Yuwei Cao

Traditional Geographic Information Systems (GIS) represent the environment under reductionist thinking, which disaggregates a geographic environment into independent geographic themes. The reductionist approach makes the spatiotemporal characteristics of geo-features explicit, but neglects the holistic nature of the environment, such as the hierarchical structure and interactions among environmental elements. To fill this gap, we integrate the concept geographic scenario with the fundamental principles of General System Theory to realize the environmental complexity in GIS. With the integration, a geographic scenario constitutes a hierarchy of spatiotemporal frameworks for organizing environmental elements and subserving the exploration of their relationships. Furthermore, we propose geo-characterization with ontological commitments to both static and dynamic properties of a geographic scenario and prescribe spatial, temporal, semantic, interactive, and causal relationships among environmental elements. We have tested the utility of the proposed representation in OWL and the associated reasoning process in Semantic Web Rule Language (SWRL) rules in a case study in Nanjing, China. The case study represents Nanjing and the Nanjing presidential palace to demonstrate the connections among environmental elements in different scenarios and the support for information queries, evolution process simulation, and semantic inferences. The proposed representation encodes geographic knowledge of the environment, makes the interactions among environmental elements explicit, supports geographic process simulation, opens opportunities for deep knowledge mining, and grounds a foundation for GeoAI to discover geographic complexity and dynamics beyond the support of conventional theme-centric inquiries in GIS.


2010 ◽  
Vol 143-144 ◽  
pp. 1305-1310
Author(s):  
Bing Li Xu ◽  
Hui Lin ◽  
Wei Ning Cui ◽  
Ya Hu ◽  
Jun Zhu ◽  
...  

Air pollution dispersion is a typical geographic process. A reasonable way to simulate air pollution dispersion is to modeling the dispersion and presents the results in a geographically referenced virtual environment. In this research, we apply the concept of virtual geographic environments (VGE), which is coined in the community of geographic information science, to facilitate air pollution dispersion by integrating MM5 and VGE. Because MM5 is computation intensive, the CUGrid is used in this research to decrease the computation time. Our research focuses on three key points, which are the platform design, MM5 integration and computation on CUGrid, and geographical visualization of air pollution dispersion in VGE. Based on the prototype system, a case of simulating air pollution dispersion in Pearl River Delta is employed to validate and test the rationality of the methodology. As shown in this case study, VGE can provide a good way to visualize air pollution dispersion and the CUGrid can decrease model computation time significantly.


2019 ◽  
Vol 15 (2) ◽  
pp. 32-53 ◽  
Author(s):  
Jayanthi Ganapathy ◽  
Uma V.

Knowledge discovery with geo-spatial information processing is of prime importance in geomorphology. The temporal characteristics of evolving geographic features result in geo-spatial events that occur at a specific geographic location. Those events when consecutively occur result in a geo-spatial process that causes a phenomenal change over the period of time. Event and process are essential constituents in geo-spatial dynamism. The geo-spatial data acquired by remote sensing technology is the source of input for knowledge discovery of geographic features. This article performs qualitative inference of geographic process by identifying events causing geo-spatial deformation over time. The evolving geographic features and their types have association with spatial and temporal factors. Event calculus-based spatial knowledge formalism allows reasoning over intervals of time. Hence, representation of Event Attributed Spatial Entity (EASE) Knowledge is proposed. Logical event-based queries are evaluated on the formal representation of EASE Knowledge Base. Event-based queries are executed on the proposed knowledge base and when experimented on, real data sets yielded comprehensive results. Further, the significance of EASE-based spatio-temporal reasoning is proved by evaluating with respect to query processing time and accuracy. The enhancement of EASE with a direction for further development to explore its significance towards prediction is discussed towards the end.


1978 ◽  
Vol 10 (2) ◽  
pp. 173-183 ◽  
Author(s):  
M Dear ◽  
G Clark

This paper provides a critical review of a long-neglected issue in geography: The role of the state in geographic processes. Five major interpretations of this role are discussed, with emphasis on their interrelationships and analytical implications: the state as supplier of public goods and services; as facilitator and regulator of the economy; as social engineer; as arbiter; and as agent of some ruling elite. This overview clarifies the question of what the state actually is, and emphasizes the significance of three crucial research issues: the legitimation and fiscal crises of the state; the role of the local state; and comparative analysis of the state in socialist systems.


2018 ◽  
Vol 10 (1) ◽  
pp. 782-796
Author(s):  
Yuwei Cao ◽  
Yi Huang ◽  
Jing Chen ◽  
YeHua Sheng

Abstract Considerable attention has been paid to geographic process-based studies in geographic information science research. Finding appropriate methods to express geographic processes is challenging, and working to reveal the dynamic evolution and underlying mechanisms behind these processes is worthwhile. This research proposes a process-centric ontology model that describes the geographical environment from three perspectives, namely, geographic scenes, geographic processes and geographic elements. These three aspects are combined to represent the dynamic changes of geographic phenomena. This research proposes a framework and constructs ten sub-ontologies. These sub-ontologies include the Element ontology, Scene ontology, and Process ontology. A soil erosion process is then selected to demonstrate the applicability of this framework. The entire process is divided into three sub-processes (detachment, transport and deposition), and each sub-process is described by identifying when and where the process occurred, the elements and their reactions, and the changes in the geographic scene. Different relationships among elements, scenes and processes are defined to explain how and why soil erosion occurred. This proposed approach can reveal the underlying mechanisms of geographic scenes, can be used to explore the occurrence and causes of geographic processes and support the complex representation of geographic elements.


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