About the operational phase
In the operational phase a web service has been realized for finding and retrieving data for the purpose of water management, initially focussing on time series for water quantity data, water quality data, and biological data.
This web service has been implemented by quite a few data providing systems as used in the Netherlands. Thus a platform has been realized that facilitates access to a large part of the water management data in the Netherlands.
The following platforms support the Digital Delta web service API (DD API):
- RWS’ distribution layer (2nd half 2018)
Water boards and other data owners who have saved their time series in a Lizard, HydroNet, Aquadesk or FEWS system can therefore easily make their data discoverable and accessible on the internet.
In any 'consuming' program (usually a viewer) the data can be searched and presented or downloaded.
The figure above shows the approach schematically.
For an overview of all available data the DD API provides catalogue functionality:
- Each connected data node provides per time series metadata that contains information about the location, the magnitude and the available times stamps.
- This way, each data node is a catalogue that can be examined by means of the DD API calls.
- A data node can retrieve the metadata from other nodes (harvesting) and add it to its own collection of metadata; the data node then is a catalogue for its own time series and the series harvested from the other data nodes.
- A central 'Digital Delta' catalogue contains the metadata of all connected data nodes, and provides a viewer to search the contents of this metadata catalogue.
The DD API specification and the metadata catalogue viewer are open source. They are available on github: https://github.com/DigitaleDeltaOrg.