Page History

...

It often happens that on an OPeNDAP server there is data available for multiple forecasts with different forecast times. If the time periods of the forecasts overlap, then only one of the forecasts can be imported at a time. If there is a separate file for each forecast, then this can be done by specifying the URL of the required file in the import configuration. However, when such data is imported in an operational system, then the import URL should be changed each time a new forecast becomes available on the OPeNDAP server. If the URLs for the different forecasts contain the forecast time and only differ in forecast time, then the tags TIME_ZERO tag or RELATIVE_TIME_IN_SECONDS can be used to solve this problem. The import will replace the any TIME_ZERO tag tags in the URL with the time zero (forecast time) of the current import run. Any RELATIVE_TIME_IN_SECONDS tags in the URL will be replaced with a time that equals (time0 + relativeTime), where time0 is the time zero (forecast time) of the current import run and relativeTime (specified in the tag) is a time relative to time0 in seconds (can be negative). The time is formatted using the dateFormat that is specified in the tag. This way different forecast data is imported each time the import runs for a different time zero.

Example of an import URL with TIME_ZERO tags:

<serverUrl>http://nomads.ncep.noaa.gov:9090/dods/gfs/gfs%TIME_ZERO(yyyyMMdd)%/gfs_%TIME_ZERO(HH)%z</serverUrl>

Example of an import URL with RELATIVE_TIME_IN_ZERO SECONDS tags:

<serverUrl>http://nomads.ncep.noaa.gov:9090/dods/gfs/gfs%TIME_ZEROgfs%RELATIVE_TIME_IN_SECONDS(yyyyMMdd, -18000 )%/gfs_%RELATIVE_TIME_%TIMEIN_ZEROSECONDS(HH,-18000)%z</serverUrl>

For more information on how to use the TIME_ZERO tag and RELATIVE_TIME_IN_SECONDS tags see server url.

Import data for a given subgrid

...