About Enhydris

General

Enhydris is a system for the storage and management of hydrological and meteorological time series.

The database is accessible through a web interface, which includes several data representation features such as tables, graphs and mapping capabilities. Data access is configurable to allow or to restrict user groups and/or privileged users to contribute or to download data. With these capabilities, Enhydris can be used either as a public repository of free data or as a private system for data storage. Time series can be downloaded in plain text format that can be directly loaded to Hydrognomon, a free tool for analysis and processing of meteorological time series.

Enhydris is free software, available under the GNU Affero General Public License, and can run on UNIX (such as GNU/Linux) or Windows. Written in Python/Django, it can be installed on every operating system on which Python runs, including GNU/Linux and Windows. It is free software, available under the GNU General Public License version 3 or any later version. It is being used by openmeteo.org, Hydrological Observatory of Athens, Hydroscope, the Athens Water Supply Company, and WQ DREAMS.

Enhydris has several advanced features:

  • It stores time series in a clever compressed text format in the database, resulting in using small space and high speed retrieval. However, the first and last few records of each time series are stored uncompressed, which means that the start and end date can be retrieved immediately, and appending a few records at the end can also be done instantly.
  • It can work in a distributed way. Many organisations can install one instance each, but an additional instance, common to all organisations, can be setup as a common portal. This additional instance can be configured to replicate data from the databases of the organisations, but without the space-consuming time series, which it retrieves from the other databases on demand. A user can transparently use this portal to access the data of all participating organisations collectively.
  • It offers access to the data through a webservice API. This is the foundation on which the above distributing features are based, but it can also be used so that other systems access the data.
  • It has a security system that allows it to be used either in an organisational setting or in a public setting. In an organisational setting, there are priviliged users who have write access to all the data. In a public setting, users can subscribe, create stations, and add data for them, but they are not allowed to touch stations of other users.
  • It is extensible. It is possible to create new Django applications which define geographical entity types besides stations, and reuse existing Enhydris functionality.

Presentations, documents, papers

Enhydris, Filotis & openmeteo.org: Free software for environmental management, by A. Christofides, S. Kozanis, G. Karavokiros, and A. Koukouvinos; FLOSS Conference 2011, Athens, 21 May 2011.

Enhydris: A free database system for the storage and management of hydrological and meteorological data, by A. Christofides, S. Kozanis, G. Karavokiros, Y. Markonis, and A. Efstratiadis; European Geosciences Union General Assembly 2011, Geophysical Research Abstracts, Vol. 13, Vienna, 8760, 2011.