Geoinformatics: Development of Community-Based Ontology and Standards for Hydrologic Data Discovery and Exchange

水文科学促进大学联盟（CUAHSI）通过CUAHSI水文信息系统（HIS）项目参与了水数据服务（WDS）的开发。WDS的愿景是将国家（可能还有地球）的水数据汇集到一个使用面向服务的体系结构连接的联邦服务器系统中。学术研究人员以及联邦和州一级的政府数据提供者都在使用CUAHSI WDS。实现这一愿景的一个关键挑战是理解和协调水文数据出版商之间的结构和语义差异。HIS项目通过开发公共关系模式（观测数据模型，ODM V1.1）、用于交换水文观测的XML模式（水标记语言，WaterML V1.0）和用于数据发现目的的水文概念原型本体（V1.0），实现了不同数据存储库之间的互操作性。经验表明，WaterML的原型和本体都需要进一步的发展。原型本体提供了测量属性之间的语义中介，但随着该本体被应用于更多样化的数据存储，很明显，i)语义异质性继续存在于各个层面，包括采样介质、采样环境、化学形态和单位，ii)本体需要涵盖更广泛的参数（例如来自EPA物质注册系统的参数）；第三，语义知识的发展需要建立在更广泛的社区基础上。WaterML已被证明是传输水信息的一种标准化方式，但需要经过正式的标准化过程。该项目将通过开发更全面、可扩展的本体来解决潜在的语义问题，该本体将ODM中包含的更通用的信息模型与来自各种现有联邦信息源的信息模型相协调。这包括开发一个不断发展的水文本体论的社区过程。此外，USGS和NCDC采用的WaterML将得到扩展，以反映这种更通用的信息模型。该项目将有助于形成一个国际标准。该项目的基本目标是组织水文概念，使出版商能够明确地描述他们的数据，并帮助用户轻松发现数据，同时精确理解所测量的属性及其上下文。

The Consortium of Universities for the Advancement of Hydrologic Science, Inc. (CUAHSI) has been involved in the development of Water Data Services (WDS) through the CUAHSI Hydrologic Information Systems (HIS) project. The vision for WDS is to bring together the nation's (and, potentially, the earth's) water data in a federated system of servers linked using a services-oriented architecture. CUAHSI WDS is used by both academic researchers and by government data providers at both the Federal and State levels. A critical challenge in achieving this vision is understanding and reconciling structural and semantic differences across publishers of hydrologic data. The HIS project achieved interoperability between different data repositories by developing a common relational schema (Observations Data Model, ODM V1.1), an XML schema for exchanging hydrologic observations (Water Markup Language, WaterML V1.0), and a prototype ontology (V1.0) of hydrologic concepts that is used for data discovery purposes. Experience has shown that the prototypes for WaterML and the ontology are in need of further development. The prototype ontology provided semantic mediation among measured properties, but as this ontology was applied to more diverse data holdings, it became apparent that i) semantic heterogeneity continued to exist at various levels, including sampled media, sampling environment, chemical speciation, and units, that ii) the ontology needs to cover a wider range of parameters (such as those from the EPA Substance Registry System), and that iii) the development of semantic knowledge needs to be put on a much broader community base. WaterML has proven to be of great utility as a standardized way for transferring water information, but needs to be moved through a formalized standardization process. This project will address the underlying semantic problem through the development of a more comprehensive, extensible ontology that harmonizes the more generic information model contained within ODM with those from various existing federal information sources. This includes the development of a community process for an evolving hydrologic ontology. In addition, WaterML, which has been adopted by USGS and NCDC, will be extended to reflect this more generic information model. The project will contribute to forming an international standard. The fundamental goal of the project is the organization of hydrologic concepts in a way that allows publishers to describe their data unambiguously and helps users to discover data easily yet with a precise understanding of the properties measured and their context.