The Observations Data Model
The Observations Data Model (ODM) is the underlying data structure for much of the data published through the CUAHSI HIS. The purpose for such a database is to enable data storage that optimizes data retrieval for integrated analysis of information collected by multiple investigators. It is intended to provide a standard format to aid in the effective sharing of information between investigators and to allow analysis of information from disparate sources within a single study area or hydrologic observatory in addition to sources across hydrologic observatories and regions. The observations data model is designed to store hydrologic observations and sufficient ancillary information (metadata) about the data values to provide traceable heritage from raw measurements to usable information allowing them to be unambiguously interpreted and used. A relational database format is used to provide querying capability to allow data retrieval supporting diverse analyses. The specifics of ODM are documented in the Water Resource Research paper, A Relational Model for Environmental and Water Resources Data and the ODM Design Specifications Document. For the most recent ODM 1.1.1 downloads, visit the HydroServer CodePlex site.
Presently, CUAHSI employs version 1.1.1 of the ODM. An NSF funded research project has led to the development of ODM2, with the goal of extending interoperability of spatially discrete, feature based earth observations derived from sensors and lab samples. To view the schema and get more information, visit the project's GitHub repository.
WaterOneFlow Web Services & WaterML
CUAHSI HydroServers use a family of web services, called WaterOneFlow (WOF), that have been developed as a standard mechanism for the transfer of time series data between hydrologic data servers (databases) and users' computers. Web services streamline the often time consuming tasks of extracting data from a data source, transforming it into a usable format, and loading it in to an analysis environment. The WaterOneFlow Web Services format the data as the type of XML, WaterML 1.1. Click here to download WaterOneFlow software and documentation.
WaterML is a strain of XML developed specifically for the sharing of water data. In the CUAHSI HIS, WaterOneFlow Web Services send requests for data while the data response is transmitted in WaterML. The CUAHSI HIS employs WaterML 1.1 at the present time, although there are some older data services registered with our catalog that are using version 1.0. Click here to download WaterML documentation and examples.
WaterML 2.0 has been developed by many of the same researchers involved in the development of WaterML 1 and is a growing international standard for transmitting water data. It has been adopted by the Open Geospatial Consortium, which is an international body that develops publicly available interface standards, and has been recommended for adoption by the World Meteorological Organization.
