Jonathan Meyer

This proposal is for the next major release of GeoServer (2.7).

• Under Discussion
• In Progress
• Completed
• Rejected
• Deferred

Provide a means to express relative time and duration queries against WMS/WCS time-enabled data.

No current support exists within the TIME parameter to construct queries relative to the present time. This proposal suggests two additions to the TIME parameter syntax that will affect WMS and WCS service calls:

1. Addition of new keyword "PRESENT" within TIME parameter values. This will be always be replaced by the current server time.
2. Allow a time period to be specified as either 1st or 2nd value of the TIME parameter, but never both. This will mirror ECQL temporal predicate syntax and provide a means to specify an offset either forward or backward in time.

GeoServer supports the WMS and WCS specs by providing "CURRENT" and "NOW" keywords respectively. Neither of these are guaranteed to represent the current server time. Instead, by default, they represent the last available data interval. This is not useful when trying to construct a deterministic relative time query.

Duration constructs already exist, but they are limited to those used to create segmented data intervals for use by WMS animation. This proposed change, when paired with the "PRESENT" keyword, will allow construction of queries that will always present the latest available data for a given time range. This is powerful when combined with feed oriented output formats such as GeoRSS and KML.

• The month of September 2002: 2002-09-01T00:00:00.0Z/P1M
• The entire day of December 25, 2010: 2010-12-25T00:00:00.0Z/P1D
• The entire day preceding December 25, 2010: P1D/2010-12-25T00:00:00.0Z
• 36 hours preceding the present time: PT36H/PRESENT

The final example could be paired with the KML service to provide a Google Earth network link always updated with the last 36 hours of data.

There has been discussion on the developer forums that can be seen in the links below. Changes have been made in response to this feedback and are reflected in updates to the pull request.

No breaking changes are made to existing TIME support as this is all new functionality.

Project Steering Committee:

• Alessio Fabiani
• Andrea Aime
• Ben Caradoc-Davies
• Christian Mueller
• Gabriel Roldán
• Jody Garnett
• Jukka Rahkonen
• Justin Deoliveira
• Phil Scadden
• Simone Giannecchini

Committers:

• Jonathan Meyer

• Email Discussion
• Pull Request 823
• JIRA 6778
• Feature Documentation