For metObs v2, oceanObs v2 and lightningdata v2 the station list represents both present and historical data about a station. This means that there can be more than one occurance of a station in the station list. This is usually due to small changes in the stations metadata (i.e., its location or height).
Each occurance of the same station has a validity period that applies to that exact combination of station metadata.
The validity period of each station occurance is denoted by the validFrom and validTo fields with validTo = null meaning no end time (forever).
Example 1:
| stationId | name | country | owner | type | status | stationHeight | barometerHeight | latitude | longitude | region | created | operationFrom | operationTo | updated | validFrom | validTo | wmoCountryCode | wmoStationId |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 04203 | Kitsissut | GRL | DMI | GIWS | Active | 11 | n/a | 76.7333 | -73.1208 | 4 | 2020-11-16 10:32:02.274 | 1980-06-15 | n/a | n/a | 1980-06-15 00:00:00.000 | 2019-01-15 13:34:47.074 | 6070 | 04203 |
| 04203 | Kitsissut | GRL | DMI | GIWS | Active | 11 | 15 | 76.7333 | -73.1208 | 4 | 2020-11-16 10:32:02.274 | 1980-06-15 | n/a | n/a | 2019-01-15 13:34:47.074 | n/a | 6070 | 04203 |
The Kitsissut barometer height was determined to be 15 at 2019-01-15 13:34:47.074, resulting in two station occurances - one denoting the stations data before 2019-01-15 13:34:47.074 and one after this point in time. Each occurance with its own distinct combination of station metadata.
Example 2:
| stationId | name | country | owner | type | status | latitude | longitude | region | created | operationFrom | operationTo | updated | validFrom | validTo | wmoCountryCode | wmoStationId |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 20098 | Frederikshavn | DNK | DMI | Tide-gauge-primary | Active | 57,4358 | 10,5475 | n/a | 2020-11-18 08:17:57.055 | 1970-01-14 | 1991-11-14 | n/a | 1970-01-14 00:00:00.000 | 1991-11-14 00:00:00.000 | n/a | n/a |
| 20098 | Frederikshavn | DNK | DMI | Tide-gauge-primary | Inactive | 57,4358 | 10,5475 | n/a | 2020-11-18 08:17:57.055 | 1970-01-14 | 1991-11-14 | n/a | 1991-11-14 00:00:00.000 | n/a | n/a | n/a |
The Frederikshavn station was decommissioned at 1991-11-14 00:00:00.000, resulting in two station occurances - one denoting the period in which the station was active and can be expected to have observations and one denoting the period after the station was decommissioned.
See also: https://en.wikipedia.org/wiki/Slowly_changing_dimension#Type_2:_add_new_row
The fields operationFrom and operationTo indicates the period in which a given station was active and registering meassurements. This information remains unchanged even for the station occurances/rows where the station is inactive due to e.g. decommissioning. See example below.
Example 3:
| stationId | name | country | owner | type | status | latitude | longitude | region | created | operationFrom | operationTo | updated | validFrom | validTo | wmoCountryCode | wmoStationId |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 20098 | Frederikshavn | DNK | DMI | Tide-gauge-primary | Active | 57,4358 | 10,5475 | n/a | 2020-11-18 08:17:57.055 | 1970-01-14 | 1991-11-14 | n/a | 1970-01-14 00:00:00.000 | 1991-11-14 00:00:00.000 | n/a | n/a |
| 20098 | Frederikshavn | DNK | DMI | Tide-gauge-primary | Inactive | 57,4358 | 10,5475 | n/a | 2020-11-18 08:17:57.055 | 1970-01-14 | 1991-11-14 | n/a | 1991-11-14 00:00:00.000 | n/a | n/a | n/a |
When using a datetime parameter in a station query, the datetime parameter applies to the operational period of a given station. If we look at the example above (example 3) this means that if you use the datetime parameter to query results for a period between 1970-01-14 and 1991-11-14, the query will return all station occurances for that given period including the occurances in which the station is inactive.
In order to avoid receiving station results where a station is inactive you need to include the status parameter which indicates whether a station is active or inactive at a specific point in time.
Below you'll see som examples on using the datetime and status parameters in a station specific query:
| Query example | Response |
|---|---|
http://receiving-server-url?status=Active&datetime=2019-12-01T00:00:00Z/2019-12-31T23:59:59Z |
Returns all stations that were active in the period 2019-12-01 to 2019-12-31 including stations that where only active in a part of the period. |
http://receiving-server-url?status=Active&datetime=2019-12-01T00:00:00Z/.. |
Returns all stations that where active at 2019-12-01 as well as active going forward |
http://receiving-server-url?status=Active&datetime=NOW |
Returns all stations that are active right now |
You can read more on how to build your query by reading our Query Primer.