Geographic modeling and simulation systems for geographic research in the new era: Some thoughts on their development and construction

Regionality,comprehensiveness,and complexity are regarded as the basic characteristics of geography.The exploration of their core connotations is an essential way to achieve breakthroughs in geography in the new era.This paper focuses on the important method in geographic research:Geographic modeling and simulation.First,we clarify the research requirements of the said three characteristics of geography and its potential to address geo-problems in the new era.Then,the supporting capabilities of the existing geographic modeling and simulation systems for geographic research are summarized from three perspectives:Model resources,modeling processes,and operational architecture.Finally,we discern avenues for future research of geographic modeling and simulation systems for the study of regional,comprehensive and complex characteristics of geography.Based on these analyses,we propose implementation architecture of geographic modeling and simulation systems and discuss the module composition and functional realization,which could provide theoretical and technical support for geographic modeling and simulation systems to better serve the development of geography in the new era.

Geographic scenario:a possible foundation for further development of virtual geographic environments

It has been two decades since virtual geographic environments(VGEs)were initially proposed.While relevant theories and technologies are evolving,data organization models have always been the foundation of VGE development,and they require further exploration.Based on the comprehensive consideration of the characteristics of VGEs,geographic scene is proposed to organize geographic information and data.We empirically find that geographic scene provides a suitable organization schema to support geo-visualization,geo-simulation,and geo-collaboration.To systematically investigate the concept and method of geographic scene,Geographic Scenario is proposed as the theory on developing geographic scene,and corresponding key issues of the Geographic Scenario are illustrated in this article.Prospects of the proposed method are discussed with the hope of informing future studies of VGEs.

Prototyping an open environment for sharing geographical analysis models on cloud computing platform

The sharing of geographical analysis models is of crucial importance for simulating geographic processes and phenomena in the current geographical information systems(e.g.Digital Earth),but there remain some issues that have not been completely resolved.The challenges include,eliminating model heterogeneity and searching for suitable infrastructures to support the open sharing and effective execution of models.Taking advantage of cloud computing,this article aims to address the above issues and develop an open environment for geographical analysis model sharing.On the basis of the analysis of the applicability of cloud computing,the architecture of the open environment is proposed.More importantly,key strategies designed for heterogeneous model description,model encapsulating as well as model deploying and transparent accessing in the cloud are discussed in detail to establish such an environment.Finally,the prototype environment is implemented,and experiments were conducted to verify the environment’s feasibility to support the sharing of geographical analysis models.

Construction of a virtual lunar environment platform

Many of the world’s powerful and wealthy nations,including China,have devoted both large amounts of funding and considerable promotion to lunar research and exploration.The launch of Chinese Chang’e-1 satellite and the construction of the scientific observation data platform created a favourable opportunity for research into the lunar geometrical,physical and chemical environment.Based on this background,a Wide Area Network(WAN)based virtual lunar environment was constructed for observation data sharing and further exploration.The systematic architecture and framework were introduced and then strategies of mass data(e.g.lunar digital elevation model,lunar digital orthophoto map and typical thematic lunar data)organisation,integration,management and scheduling were then set up to achieve the 3D visualisation of typical lunar geomorphic features.Furthermore,the integration method of 3D lunar data and the process model of impact craters were studied;thus,the whole lunar and celestial collision process could be dynamically simulated.The results indicate that the WAN-based virtual lunar platform can be used effectively for public information sharing,scientific exploration and further to promote the development of deep space exploration in China.

A model-service deployment strategy for collaboratively sharing geo-analysis models in an open web environment

Geo-analysis models can be shared and reused via model-services to support more effective responses to risks and help to build a sustainable world.The deployment of model-services typically requires significant effort,primarily because of the complexity and disciplinary specifics of geo-analysis models.Various modelling participants engage in the collaborative modelling process:geo-analysis model resources are provided by model providers,computational resources are provided by computational resource providers,and the published model-services are accessed by model users.This paper primarily focuses on model-service deployment,with the basic goal of providing a collaboration-oriented method for modelling participants to conveniently work together and make full use of modelling and computational resources across an open web environment.For model resource providers,a model-deployment description method is studied to help build model-deployment packages;for computational resource providers,a computational resource description method is studied to help build model-service containers and connectors.An experimental system for sharing and reusing geo-analysis models is built to verify the capability and feasibility of the proposed methods.Through this strategy,modellers from dispersed regions can work together more easily,thus providing dynamic and reliable geospatial information for Future Earth studies.

A framework on task configuration and execution for distributed geographical simulation

Geographical simulation is a popular method in geographical and environmental research.Many models developed to address geographic and environmental issues are distributed worldwide.However,due to the lack of portals,these models are still difficult to invoke for geographical simulations in open web environments.This study designs and develops a framework to assemble service-oriented models from volunteers distributed worldwide for geographical simulations on the web.The framework consists of three layers(task layer,data exchange layer,and model execution layer)that establish a network of serviceoriented locally shared models and simulation tasks for user configurations.With the help of such a framework,users can configure simulation tasks and invoke suitable models shared worldwide for geographical simulations.This article provides an application of the distributed simulation of gross primary production(GPP)by the Biome-BioGeochemical Cycles(BGC)model in China.This application shows that the framework can be beneficial for model assembly from volunteers’computers and distributed simulation tasks that are run for geographical and environmental issues,which can be applied to Digital Earth initiatives.

A new academic impact metric for evaluating geographic simulation models

Geographic simulation models can be used to explore and better understand the geographical environment. Recent advances in geographic and socio-environmental research have led to a dramatic increase in the number of models used for this purpose. Some model repositories provide opportunities for users to explore and apply models,but few provide a general evaluation method for assessing the applicability and recognition of models. In this study,an academic impact evaluation method for models is proposed. Five indices are designed based on their pertinence. The analytical hierarchy process is used to calculate the index weights,and the academic impacts of models are quantified with the weighted sum method. The time range is controlled to evaluate the life-term and annual academic impacts of the models. Some models that met the evaluation criteria from different domains are then evaluated. The results show that the academic impact of a model can be quantified with the proposed method,and the major research areas that models impact are identified.

A topological framework for real-time 3D weather radar data processing

Real-time 3D weather radar data processing makes it possible to efficiently simulate meteorological processes in digital Earth and support the assessment of meteorological disasters.The current real-time meteorological operation system can only deal with radar data within 2D space as a flat map and lacks supporting 3D characteristics.Thus,valuable 3D information imbedded in radar data cannot be completely presented to meteorological experts.Due to the large amount of data and high complexity of radar data 3D operation,regular methods are not competent for supporting real-time 3D radar data processing and representation.This study aims to perform radar data 3D operations with high efficiency and instant speed to provide real-time 3D support for the meteorological field.In this paper,a topological framework composed of basic inner topological objects is proposed along with the quadtree structure and LOD architecture,based on which 3D operations on radar data can be conducted in a split second and 3D information can be presented in real time.As the applications of the proposed topological framework,two widely used 3D algorithms in the meteorological field are also implemented in this paper.Finally,a case study verifies the applicability and validity of the proposed topological framework.