Time Support in GeoServer WMS¶

Specifying a time¶

The format used for specifying a time in the WMS TIME parameter is based on ISO-8601. Times may be specified up to a precision of 1 millisecond; GeoServer does not represent time queries with more precision than this.

The parameter is:

TIME=<timestring>

Times follow the general format:

yyyy-MM-ddThh:mm:ss.SSSZ

where:

• yyyy: 4-digit year

• MM: 2-digit month

• dd: 2-digit day

• hh: 2-digit hour

• mm: 2-digit minute

• ss: 2-digit second

• SSS: 3-digit millisecond

The day and intraday values are separated with a capital T, and the entire thing is suffixed with a Z, indicating UTC for the time zone. (The WMS specification does not provide for other time zones.)

GeoServer will apply the TIME value to all temporally enabled layers in the LAYERS parameter of the GetMap request. Layers without a temporal component will be served normally, allowing clients to include reference information like political boundaries along with temporal data.

Specifying an absolute interval¶

A client may request information over a continuous interval instead of a single instant by specifying a start and end time, separated by a / character.

In this scenario the start and end are inclusive; that is, samples from exactly the endpoints of the specified range will be included in the rendered tile.

Specifying a relative interval¶

A client may request information over a relative time interval instead of a set time range by specifying a start or end time with an associated duration, separated by a / character.

One end of the interval must be a time value, but the other may be a duration value as defined by the ISO 8601 standard. The special keyword PRESENT may be used to specify a time relative to the present server time.

Reduced accuracy times¶

The WMS specification also allows time specifications to be truncated by omitting some of the time string. In this case, GeoServer treats the time as a range whose length is equal to the most precise unit specified in the time string.

For example, if the time specification omits all fields except year, it identifies a range one year long starting at the beginning of that year.

Reduced accuracy times with ranges¶

Reduced accuracy times are also allowed when specifying ranges. In this case, GeoServer effectively expands the start and end times as described above, and then includes any samples from after the beginning of the start interval and before the end of the end interval.

Specifying a list of times¶

GooServer can also accept a list of discrete time values. This is useful for some applications such as animations, where one time is equal to one frame.

The elements of a list are separated by commas.

If the list is evenly spaced (for example, daily or hourly samples) then the list may be specified as a range, using a start time, end time, and period separated by slashes.

Specifying a periodicity¶

The periodicity is also specified in ISO-8601 format: a capital P followed by one or more interval lengths, each consisting of a number and a letter identifying a time unit:

The Year/Month/Day group of values must be separated from the Hours/Minutes/Seconds group by a T character. The T itself may be omitted if hours, minutes, and seconds are all omitted. Additionally, fields which contain a 0 may be omitted entirely.

Fractional values are permitted, but only for the most specific value that is included.

For example, the multiple representations listed below are all equivalent.

• One hour:

  P0Y0M0DT1H0M0S
  
  PT1H0M0S
  
  PT1H
  

• 90 minutes:

  P0Y0M0DT1H30M0S
  
  PT1H30M
  
  P90M
  

• 18 months:

  P1Y6M0DT0H0M0S
  
  P1Y6M0D
  
  P0Y18M0DT0H0M0S
  
  P18M
  

  Note

  P1.25Y3M would not be acceptable, because fractional values are only permitted in the most specific value given, which in this case would be months.