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

大学水文科学促进联盟(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的愿景是将国家的(可能是地球的)水数据整合到一个使用面向服务的架构连接的联合服务器系统中。CUAHSI WDS既由学术研究人员使用，也由联邦和州两级的政府数据提供商使用。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项目通过开发通用关系模式(观测数据模型，ODM V1.1)、用于交换水文观测的XML模式(Water Markup Language，Water ML V1.0)和用于数据发现目的的水文概念的原型本体(V1.0)，实现了不同数据储存库之间的互操作性。经验表明，WatML和本体的原型还需要进一步的开发。原型本体在测量的属性之间提供了语义中介，但随着该本体应用于更多样化的数据持有，很明显，i)语义异质性继续存在于不同的水平，包括采样介质、采样环境、化学物种形成和单元，ii)本体需要涵盖更广泛的参数(如来自EPA物质登记系统的参数)，以及iii)语义知识的开发需要放在更广泛的社区基础上。事实证明，WatML作为传输水信息的标准化方式非常有用，但需要通过正式的标准化过程进行迁移。该项目将通过开发一个更全面、可扩展的本体论来解决根本的语义问题，使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模型相协调。这包括为不断演变的水文本体论制定一个社区进程。此外，已经被USGS和NCDC采用的WaterML将被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项国际标准。该项目的基本目标是组织水文概念，使出版商能够明确描述其数据，并帮助用户在准确了解所测量的特性及其背景的情况下轻松地发现数据。

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.