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Most Web Map capabilities documents list each timestamp available for each layer. This is fine for services that provide a relatively small number of timestamps. The addition of hindcast to our Web Map datasets, providing from 12 months up-to 5 years of historical tiles, means that our capabilities documents can contain anywhere up-to 15,000 timestamps for each layer, resulting in a file that is both slow to produce, transfer and transferparse.

In order to avoid this problem, the Tidetech WMTS has adopted the convention used by NASA in their Global Imagery Browse Services (GIBS), and other organisations, which allows them to serve historical imagery going back yearsover any temporal range.

Rather than listing each timestamp, this convention describes the minimum timestamp, maximum timestamp, and the duration of the timestep.

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As you can see, the Value tag now contains three values separated by "/" - the start_timestamp, end_timestamp, and timestep_duration. The duration is specified as a an ISO8601 duration, see https://en.wikipedia.org/wiki/ISO_8601#Durations. For more information on GIBS see https://developer.earthdata.nasa.gov/gibs/gibs-api-for-developers#GIBSAPIforDevelopers-TimeDimension.

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