面向虚拟地理环境的Linux平台地理分析模型服务化封装方法

地理分析模型是对现实世界中地理过程的抽象与表达,是虚拟地理环境能够反映真实世界的重要工具。随着地理学的发展,跨领域、多学科合作式地理建模逐渐成为地理学的研究趋势,地理分析模型共享与重用也已经成为研究热点之一。然而,地理分析模型运行平台的差异性导致了其在共享与重用上存在困难,表现在用户难以直接透明共享不同平台下的模型。目前,地理分析模型运行平台主要包含Windows与Linux,Linux平台上存在大量模型,但相关模型服务共享与重用研究相对较少。本文面向Linux平台不同操作系统,分析其差异性及安全性,设计模型服务化的安全策略;面向Linux平台下地理分析模型的异构特征,设计了模型基本信息描述接口、行为接口及部署接口,实现Linux系统下地理分析模型的服务共享与重用。本文以system for automated geoscientific analyses（SAGA GIS）中的网格分析模型为例,对所设计的Linux平台下地理分析模型服务化封装方法进行了验证,显示了所设计封装策略的可行性,为Linux平台下地理分析模型的共享与重用提供了理论与方法基础。     

A loosely integrated data configuration strategy for web-based participatory modeling

Participatory modeling is an important approach for solving complex geo-problems from a comprehensive and holistic viewpoint, and it brings together stakeholders from multiple disciplines to provide diverse resources, including modeling, data fields and computational assets. Data configuration work (e.g., preparing appropriate input data for model execution, connecting a model’s output to the input data of another model) is important for constructing and executing a participatory modeling task. Most current data configuration methods depend on the model integration logic, which presents a challenge when adding new modeling resources into a model to dynamically create and execute new modeling tasks. To support the construction of participatory modeling tasks in a web environment, this article proposes a loosely integrated data configuration strategy for decoupling data configuration work from the execution process of a participatory modeling task. A model service controller is designed for model input/output (I/O) configuration, and a data service controller is designed for data access configuration. These two controllers can help modelers link the data I/O demands of a model-service with the appropriate data-services; thus, different modeling instances can be dynamically joined to a participatory modeling task and executed without reconstructing the original data configuration settings. A prototype participatory modeling system is proposed to demonstrate the flexibility and feasibility of the proposed method using an experimental modeling case. The results show that the proposed data configuration strategy supports the integration of different model-services based on the data dependency relationships and that the complexity and difficulty in configuring data for a participatory modeling tasks in the web environment are minimized.     

面向地理分析模拟的城市小区场景数据组织方法

城市小区是城市人居环境的重要构成部分,与城市居民生活关系密切。面向城市小区环境综合分析模拟的需求,本文结合虚拟地理环境中虚拟场景和集成建模等概念,设计了可支撑分析模拟的城市小区场景数据组织方法。通过小区系统、小区系统要素和小区系统要素关系来对复杂小区环境信息进行对象化的描述,并按照层次化结构实现城市小区建模场景的组织。利用统一数据表达与交换模型UDX对小区系统-要素-关系中的数据内容进行统一的表达和存储,在此基础上设计了城市小区建模场景对象;利用可扩展接口的方式,实现从城市小区建模场景中抽取符合分析模型需求的数据内容,由此支撑将不同地理分析模型与城市小区建模场景集成。试验结果表明,本文所设计的方法能够有效组织多源异构的城市小区环境数据,并可以便捷地为不同研究方向的城市小区分析模型提供所需建模数据。     

Simulation Modelling Applied to Runoff Modelling Using MapScript

Dynamic spatial analysis addresses computational aspects of space–time processing. This paper describes the development of a spatial analysis tool and modelling framework that together offer a solution for simulating landscape processes. A better approach to integrating landscape spatial analysis with Geographical Information Systems is advocated in this paper. Enhancements include special spatial operators and map algebra language constructs to handle dispersal and advective flows over landscape surfaces. These functional components to landscape modelling are developed in a modular way and are linked together in a modelling framework that performs dynamic simulation. The concepts and modelling framework are demonstrated using a hydrological modelling example. The approach provides a modelling environment for scientists and land resource managers to write and to visualize spatial process models with ease.     

基于开放互操作标准的分布式地理空间模型共享研究

传统的单机环境和封闭式网络环境由于有限的资源利用能力, 难以充分支持分散地学数据、模型等资源的共享与应用集成。基于网络环境的信息交换特点, 提出了分布式地理空间模型共享的服务体系。该体系以数据、模型、元数据等互操作要素为核心, 通过网络将数据、模型等网络节点进行开放式耦合。针对地理空间模型服务的互操作问题, 提出了分布式环境下的模型共享服务交互接口, 该接口定义了模型服务元数据、模型服务的交互操作、模型服务的通讯方式等交互规则, 尽可能地降低模型服务与模型终端之间在数据交换、功能调用等方面的互操作困难。为了降低将模型共享为模型服务的实现难度, 设计和开发了地理空间模型共享平台, 并介绍了在该平台上发布地理空间模型的2种方法。最后介绍了研究成果在Prairie生态模型共享方面的应用实践。     

模型库系统平台的研究

模型库系统平台是一个独立于具体应用领域，对模型进行分类和维护，支持模型生成、存储、查询、运行和分析应用的软件系统。它是一个模型库系统的开发环境，各个领域的专家和用户都能利用它快速有效地建立其特定领域的模型库。该文提出了模型库系统平台的思想和总体框架，探讨了系统关键技术的实现以及系统的功能，并给出了模型库系统平台在海洋渔业服务领域的应用实例和效果分析。     

A Framework and Software Tool to Support Collaborative Landscape Analysis: Fitting Square Pegs into Square Holes

For landscape models to be applied successfully in management situations, models must address appropriate questions, include relevant processes and interactions, be perceived as credible and involve people affected by decisions. We propose a framework for collaborative model building that can address these issues, and has its roots in adaptive management, computer‐supported collaborative work and landscape ecology. Models built through this framework integrate a variety of information sources, address relevant questions, and are customized for the particular landscape and policy environment under study. Participants are involved in the process from the start, and because their input is incorporated, they feel ownership of the resulting models, increasing the chance of model acceptance and application. There are two requirements for success: a tool that supports rapid model prototyping and modification, that makes a clear link between a conceptual and implemented model, and that has the ability to implement a wide range of model types; and a core team with skills in communication, research and analysis, and knowledge of ecology and forestry in addition to modelling. SELES (Spatially Explicit Landscape Event Simulator) is a tool for building and running models of landscape dynamics. It combines discrete event simulation with a spatial database and a relatively simple modelling language to allow rapid development of landscape simulations, and provides a high‐level means of specifying complex model behaviours ranging from management actions to natural disturbance and succession. We have applied our framework in several forest modelling projects in British Columbia, Canada. We have found that this framework increases the interest by local experts and decision‐makers to participate actively in the model building process. The workshop process and resulting models have efficiently provided insight into the dynamics of large landscapes over long time frames. The use of SELES has facilitated this process by providing a flexible, transparent environment in which models can be rapidly implemented and refined. As a result, model findings may be more readily incorporated into decision‐support systems designed to assist resource managers in making informed decisions.     

The PCRaster Software and Course Materials for Teaching Numerical Modelling in the Environmental Sciences

Teaching numerical modelling in the environmental sciences not only needs good software and course material but also an understanding of how to program the models in the computer. Conventional environmental modelling procedures require computer science and programming skills, which may detract from the important understanding of the environmental processes involved. An alternative strategy is to build a generic toolkit or modelling language that operates with concepts and operations that are familiar to the environmental scientist. PCRaster is such a spatio-temporal environmental modelling language developed at Utrecht University, the Netherlands. It is used for teaching modelling in classrooms and over the Web (distance learning) at three levels: (1) explaining environmental processes and models, where models with a fixed structure of model equations are evaluated by changing model parameters, (2) teaching model construction, where students learn to program spatial and temporal models with the language, and (3) teaching all phases of scientific modelling related to field research. So far, we have received positive responses to these courses, largely because the software provides a set of easily learned functions matching the conceptual thought processes of a geoscientist that can be used at all levels of teaching.     

Enabling Digital Earth simulation models using cloud computing or grid computing – two approaches supporting high-performance GIS simulation frameworks

Abstract

Geospatial simulation models can help us understand the dynamic aspects of Digital Earth. To implement high-performance simulation models for complex geospatial problems, grid computing and cloud computing are two promising computational frameworks. This research compares the benefits and drawbacks of both in Web-based frameworks by testing a parallel Geographic Information System (GIS) simulation model (Schelling's residential segregation model). The parallel GIS simulation model was tested on XSEDE (a representative grid computing platform) and Amazon EC2 (a representative cloud computing platform). The test results demonstrate that cloud computing platforms can provide almost the same parallel computing capability as high-end grid computing frameworks. However, cloud computing resources are more accessible to individual scientists, easier to request and set up, and have more scalable software architecture for on-demand and dedicated Web services. These advantages may attract more geospatial scientists to utilize cloud computing for the development of Digital Earth simulation models in the future.     

An integrated virtual geographic environmental simulation framework: a case study of flood disaster simulation

Dynamic flood disaster simulation is an emerging and promising technology significantly useful in urban planning, risk assessment, and integrated decision support systems. It is still an important issue to integrate the large assets such as dynamic observational data, numerical flood simulation models, geographic information technologies, and computing resources into a unified framework. For the intended end user, it is also a holistic solution to create computer interpretable representations and gain insightful understanding of the dynamic disaster processes, the complex impacts, and interactions of disaster factors. In particular, it is still difficult to access and join harmonized data, processing algorithms, and models that are provided by different environmental information infrastructures. In this paper, we demonstrate a virtual geographic environments-based integrated environmental simulation framework for flood disaster management based on the notion of interlinked resources, which is capable of automated accumulating and manipulating of sensor data, creating dynamic geo-analysis and three-dimensional visualizations of ongoing geo-process, and updating the contents of simulation models representing the real environment. The prototype system is evaluated by applying it as a proof of concept to integrate in situ weather observations, numerical weather and flood disaster simulation models, visualization, and analysis of the real time flood event. Case applications indicate that the developed framework can be adopted for use by decision-makers for short-term planning and control since the resulting simulation and visualization are completely based on the latest status of environment.     

Putting meaning into NETMAR – the open service network for marine environmental data

The open service network for marine environmental data (NETMAR) project uses semantic web technologies in its pilot system which aims to allow users to search, download and integrate satellite, in situ and model data from open ocean and coastal areas. The semantic web is an extension of the fundamental ideas of the World Wide Web, building a web of data through annotation of metadata and data with hyperlinked resources. Within the framework of the NETMAR project, an interconnected semantic web resource was developed to aid in data and web service discovery and to validate Open Geospatial Consortium Web Processing Service orchestration. A second semantic resource was developed to support interoperability of coastal web atlases across jurisdictional boundaries. This paper outlines the approach taken to producing the resource registry used within the NETMAR project and demonstrates the use of these semantic resources to support user interactions with systems. Such interconnected semantic resources allow the increased ability to share and disseminate data through the facilitation of interoperability between data providers. The formal representation of geospatial knowledge to advance geospatial interoperability is a growing research area. Tools and methods such as those outlined in this paper have the potential to support these efforts.     

国土资源数据集成与服务技术研究

国土资源数据集成管理体系是连接诸中心综合信息库、各分节点区域信息库的分布式空间信息集成管理系统,它主要在分布式、多源异构的国土资源数据环境下提供数据汇聚、数据集成、数据发现、数据访问和数据服务等功能,为各类用户和应用系统提供广泛有效的数据共享和交换服务。针对国土资源数据具有的多源、多级服务等需求特征,本文分析了集成模式,应用服务结构和服务请求消息流程与协议等技术,以期对分布式网络环境下的国土资源数据一体化集成和动态服务提供支撑。     

Improving the reliability of landslide susceptibility mapping through spatial uncertainty analysis: a case study of Al Hoceima,Northern Morocco

This paper aims at providing an answer as to whether generalization obtained with data-driven modelling can be used to gauge the plausibility of the physically based (PB) model’s prediction. Two statistical models namely; Weight of Evidence (WofE) and Logistic Regression (LR), and a PB model using the infinite slope assumptions were evaluated and compared with respect to their abilities to predict susceptible areas to shallow landslides at the 1:10.000 urban scale. Threshold-dependent performance metrics showed that the three methods produced statistically comparable results in terms of success and prediction rates. However, with the Area Under the receiver operator Curve (AUC), statistical models are more accurate (88.7 and 84.6% for LR and WofE, respectively) than the PB model (only 69.8%). Nevertheless, in such data-sparse situation, the usual approaches for validation, i.e. comparing observed with predicted data, are insufficient, formal uncertainty analysis (UA) is a means for evaluating the validity and reliability of the model. We then refitted the PB model using a stochastic modification of the infinite slope stability model input scheme using Monte Carlo (MC) method backed with sensitivity analysis (SA). For statistical models, we used an informal Student t-test for estimating the certainty of the predicted probability (PP) at each location. Both modelling outputs independently show a high validity; and whereas the level of confidence in LR and WofE models remained the same after performance re-evaluation, the accuracy of the PB model showed an improvement (AUC = 72%). This result is reasonable and provides a further validation of PB model. So, in urban slope analysis, where PB diagnostic is necessary, statistical and PB modelling may play equally supportive roles in landslide hazard assessment.     

Reality-based generation of virtual environments for digital earth

Abstract

Digital Earth essentially consists of 3D and moreD models and attached semantic information (attributes). Techniques for generating such models efficiently are required very urgently. Reality-based 3D modelling using images as prime data source plays an important role in this context. Images contain a wealth of information that can be advantageously used for model generation. Images are increasingly available from satellite, aerial and terrestrial platforms. This contribution briefly describes some of the problems which we encounter if the process of model generation is to be automatised. With the help of some examples from Digital Terrain Model generation, Cultural Heritage and 3D city modelling we show briefly what can be achieved. Special attention is directed towards the use of model helicopters for image data acquisition. Some problems with interactive visualisation are discussed. Also, issues surrounding R&D, professional practice and education are also addressed.     

SCOPED‐W: SCalable Online Platform for extracting Environmental Data and Water‐related model outputs

This article presents SCOPED, an innovative approach for extracting environmental data using OGC services. In the field of water resource management, SCOPED‐W (‘W’ for ‘Water’) is a method that was developed in the framework of EU/FP7 IASON and EOPOWER projects. This platform supports the collection of data required to build a Soil and Water Assessment Tool (SWAT) model and the uptake, spatialization and dissemination of raw data generated from the outputs of different SWAT models for the Black Sea region. Scientists are documenting the data served by the platform in ISO standardized metadata to support informed use. SCOPED‐W primarily targets the community of SWAT users in the Black Sea region but it can easily be replicated in other geographical areas. Additionally, the SCOPED approach is based on data interoperability that makes it fully compatible with other domains of application as demonstrated here with three original use cases. The article also highlights the benefits of the approach for the GEO community and discusses future improvements for supporting integration with other platforms such as UNEP Live.     

Accuracy improvement of ASTER stereo satellite generated DEM using texture filter

The grid DEM(digital elevation model) generation can be from any of a number of sources:for instance,analogue to digital conversion of contour maps followed by application of the TIN model,or direct elevation point modelling via digital photogrammetry applied to airborne images or satellite images.Currently,apart from the deployment of point-clouds from LiDAR data acquisition,the generally favoured approach refers to applications of digital photogrammetry.One of the most important steps in such deployment i...     

基于随机过程的格网DEM精度场模型

针对目前DEM格网精度从理论上难于统一量化描述问题,提出一种基于随机过程的格网DEM（grid digital elevation model, grid DEM）精度场模型,该模型从随机过程理论入手,借助DEM的统一插值模型,建立了DEM两类误差（噪声误差和逼近误差）的数学表达,并分析了构成DEM误差的各个分量的数学意义。与已有的模型相比,该模型实现了传统DEM两类误差的统一描述,此外,该模型适用任意插值方式生成的格网DEM的精度评价。     

基于XML地理信息资源统一检索

针对各类型地理信息资源描述信息的异构问题,采用"名称,属性值,单位"三元组形式充分容纳异构信息,并运用面向对象的思想将资源个体的描述转换为XML文件中的节点元素。基于该描述方式对矢量、影像、文本等常见类型的资源进行描述,并将描述信息录入XML文件中。基于XML数据文件开展地理信息资源检索实验,实验证明,该方法能够对异构信息统一处理,实现了多种类型地理信息资源的统一检索。