The CUAHSI Hydrologic Information System

The CUAHSI Hydrologic Information System (HIS) is an internet-based system for sharing hydrologic time series data. It is comprised of databases and servers, connected through web services, to client applications, allowing for the publication, discovery and access of water data.

There are three types of computers that store and process data in the CUAHSI HIS:

HIS Central: This is the Central Catalog. It contains copies of metadata which facilitates searches. It operates similarly to a search engine, in that it harvests metadata from the data servers and allows it to be efficiently searched by the clients.

HydroServer: stores, organizes and publishes data; allows metadata to be harvested by HIS Central and data to be shared with clients.

Client: Software that gives users a convenient interface to access data. The first major role of the software clients is to enable data discovery by exposing metadata. For users wanting to find data, this is important as it allows a user to understand the data, and its source, before actually downloading the data. The second important role of the clients is to enable actual data download from HydroServers.
Different clients have different capabilities for analyzing data. For example, HydroDesktop is a GIS-enabled application with extensions that enable statistical analysis and modeling. HydroExcel is a Microsoft Excel spreadsheet with built in VBA macros that can access data registered with HIS Central, but has only minimal analysis tools such as creating a graph of data downloaded.

These three points of the HIS Triangle are tied together by web services, which are applications that facilitate the exchange of information over the internet. More on these soon.

For more information, visit the HIS website!