【作者】 朱睿；

【导师】 刘勇；

【作者基本信息】 兰州大学 ， 地图学与地理信息系统， 2014， 博士

【摘要】 在环境建模领域,由于大多数地学模型算法复杂且参数众多,研究人员需要花费大量的时间精力学习如何使用模型及制备输入数据,而且这类模型通常只能在本地计算机上运行,这就限制了模型的推广应用程度和与其它模型的互操作性。SWAT (Soil and Water Assessment Tool)模型是地学模型最优秀代表之一,于1994年由美国农业部研发成功以来,在全球得到了广泛应用,成为水资源及生态环境领域科研与水文业务的重要工具。但是,目前在模型及其输出数据的共享和互操作方面仍存在很大困难,解决该问题的关键是需要构建一个基于Webservices的地理信息服务(Geographic Information Web Services, GISevrices)平台,进而实现人-信息-计算工具协同工作的互动环境。Web services技术是将应用程序通过标准接口以独立组件的形式发布在Internet上,可以被网上的用户调用及直接使用,也可以和其它服务进行松散耦合和数据交换。基于Web services发展的地理信息服务是对地理数据服务和地理处理服务的统称,是提高地学领域数据共享程度、空间分析和地理处理互操作性的最有效途径。目前地理信息服务的研究主要集中在数据服务和简单的空间分析服务,对较复杂的地理处理服务和更复杂的环境建模服务的研究相对较少。地理信息服务在水文水资源领域的应用也主要集中在数据服务的发布、集成和处理,将地理信息服务提升到模型(如SWAT模型)层面是亟待解决的前沿问题。针对以上问题,本文探析了基于GIServices的SWAT水文模型服务的实现机制,完成了将SWAT模型以Web services的方式在网上发布,支持跨平台和异构环境的调用和集成。为科研人员通过服务接口调用SWAT水文模型服务并直接进行模拟处理,或者将其集成到用户自己的模型中提供了有效途径。本文主要研究成果如下：(1)在深入研究Web services、地理信息服务、地理处理服务的理论背景和关键技术的基础上,从水文模型服务的实现方法、服务链工作流模式、服务性能制约因素、事务模式和服务粒度设定等多个方面,研究和阐述了水文模型发布为地理信息服务的关键理论和技术问题,提出了基于GIServices的SWAT水文模型服务的实现机制,包括理论框架和技术框架两部分,为实现SWAT模型的Web服务奠定了基础。(2)基于提出的SWAT水文模型服务的理论机制和技术框架,构建了SWAT模型水文循环部分所有处理过程的Web服务,即SWAT Web Services,可以广泛应用于在线SWAT水文模拟和基于SWAT模型服务的应用程序创建。SWAT Web Services共包括10个自定义的服务,分别是流域离散化、水文响应单元(HRU)分析、气象数据空间展布、积雪、土壤温度、蒸散发、地表径流、壤中流、地下径流和土壤含水量服务,各服务可以单独调用,也可以进行服务组合。(3)基于发布的SWAT Web Services和地理信息服务开源软件平台开发了一个WebGIS原型系统——黑河干流山区水文信息服务及可视化系统。该系统能够通过调用SWAT模型服务实现SWAT模型的在线操作,并实现了二维、三维联动的水文模拟结果空间可视化、基于水文响应单元和水文站点的逐日水文信息时空查询功能、空间数据查询和空间分析等功能。综上所述,基于Web services的地理信息服务为提高SWAT模型的互操作性和深层集成提供了有效的技术支持。SWAT水文模型服务可将原来在本地计算机运行的水文模型通过标准的服务接口在网上发布,大大提高了SWAT模型及其模拟结果的可访问性、互操作性和应用范围。此外,由SWAT水文模型服务研发的原型系统(黑河干流山区水文信息服务及可视化系统)中二维、三维联动的地学可视化功能,可有助于加深对水文过程的理解,便于多尺度时空查询及下载应用。总之,本文构建的SWAT水文模型服务有望成为模型层面服务的新范式。更多还原

【Abstract】 In the field of environmental modeling, most algorithms of geoscientific models are so complex that the users require considerable time to learn how to use them and to prepare the complicated input data. Moreover, these geospatial modules or models are developed and used on a local machine. This situation limits the application and interoperability of geospatial algorithms or environmental models.SWAT (Soil and Water Assessment Tool) model, which was developed by United States Department of Agriculture in1994, is one of the most outstanding and representative geoscientific models. SWAT model has been widely applied in the fields of water resource and ecological environment all over the world. But there are still a lot of limits in sharing and interoperability for the model as well as its simulated result. The critical solution for these challenges is to build a Geographic Information Web Services (GIServices) platform as an interactive environment so as to allow collaborative work among researchers, information and computing equipment.Web services are self-defined independent software components accessible over the Internet with standard interfaces to describe a set of operations. The end user can invoke and execute a Web services or bind together different Web services to build their own application. Geographic Information Web services (GIServices), arised with Web services applied in GIS, are Web services that enable users to access geographic information, geoprocessing tools, and environmental models via the Internet. GIServices provide an effective solution to increase geospatial data sharing and geoprocessing interoperability. Most existing GIServices remain in the level of geospatial data and simple geospatial analytical services, so there is little research in complicated geoprocessing services and more complicated environmental models as Web services. Moreover, GIServices in hydrology are mainly concentrated in releasing data services. Therefore, to promote GIServices from data services level to models services level (e.g. SWAT model) is a cutting edge problem to be solved urgently.Aiming at above problems, this paper explored the realization mechanism to publish SWAT model as GIServices and implemented the SWAT model exposed as Web services accessed over the internet, supporting to be invoked and integrated at cross-platform and heterogeneous environment. It is a valid approach to allow researchers to invoke SWAT Web services and then execute simulation processing, or integrate them to their own applications.The main achievements of this dissertation are as follows.(1) In the basis of analyzing difference between geospatial calculations and hydrologic modeling algorithm, a design and implementation strategy for establishing models Web services for SWAT based on GIServices was proposed considering implementation methods, workflow types and transaction patterns of service chain, service granularity balance and other aspects. The design and implementation strategy consists of theoretical framework and technical framework. In the proposed process, to overcome technical challenges, such as the large amount of data required by hydrological models, complex algorithm and time-consuming execution of hydrological models and so on, should be fully taken into account in the research.(2) Relying on the theoretical and technical framework of the design and implementation strategy, SWAT was deployed to be exposed as hydrological model services named SWAT Web Services. The SWAT Web Services include ten atomic services developed using our approach, which were Watershed Delineation Service, HRU (Hydrological Response Units) Analysis Service, WeatherData Distribution Service, Snow Service, Soil Temperature Service, Evapotranspiration Service, Surface Runoff Service, Lateral Flow Service, Groundwater Flow Service and Soil Water Service.(3) A prototype WebGIS system was provided on account of free softwares to achieve SWAT simulation online by invoking SWAT Web Services, which was Hydrological Information Services and Visualization system for Mountainous Watershed of Heihe Mainstream River. The prototype system was emphasized in functionalities as follows,2D and3D visualized interaction for hydrological simulated results and geospatial information, daily spatio-temporal query for hydrological information on any HRUs and hydrological stations, geospatial data query and geospatial analysis.In conclusion, GIServices, grown along with Web services, offers effective support to increase interoperability and deep integration for SWAT model. Via released standard interfaces online, SWAT Web Services dramatically promote the accessibility, interoperability and sharing of SWAT and its outputs among different researchers. In addition, the prototype WebGIS system based on the adoption of SWAT Web services proved that the strategy for establishing SWAT Web services proposed in this research is feasible and practicable. The dynamical2D and3D geovisualized interaction implemented in the prototype system facilitate scientists in improving the understanding of hydrological processes, and daily spatio-temporal query and download of hydrological information on HRUs have enhanced the application scope of SWAT simulated results in future analysis. In summary, SWAT Web Services presented in this research is expected to become a new paradigm for GIServices in models level.更多还原