GetObservation with no temporal filter returning too many values

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GetObservation with no temporal filter returning too many values

TSlawecki
I have now successfully entered about 8,000 measurements using a ResultTemplate. When I do a straight GetObservation request with no temporal filter, I get all of the measurements back. However, the "OGC Sensor Observation Service 2.0 Hydrology Profile" states:

If a GetObservation request does not contain a temporal filter the service shall only return the latest value of each time series instead of the full content.

Can someone explain why 52N SOS 4.3.6 is not operating this way? Two thoughts that came to mind are:

 - There is a configuration option - perhaps "Maximum number of returned observation values" that I missed

  - Entering the data through the ResultTemplate is somehow making SOS think the time series is a single observation

Suggestions appreciated!

Thanks in advance - Tad
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Re: GetObservation with no temporal filter returning too many values

Carsten Hollmann
Hi Tad,

> I have now successfully entered about 8,000 measurements using a
> ResultTemplate. When I do a straight GetObservation request with no temporal
> filter, I get all of the measurements back. However, the "OGC Sensor
> Observation Service 2.0 Hydrology Profile" states:
>
> If a GetObservation request does not contain a temporal filter the service
> shall only return the latest value of each time series instead of the full
>
> Can someone explain why 52N SOS 4.3.6 is not operating this way?

The 52N SOS is an implementation of the OGC SOS 2.0 standard and
corresponds to the behavior, as defined therein.

The "OGC Sensor Observation Service 2.0 Hydrology Profile" is an profile
for the OGC SOS 2.0 that partially restricted the default behavior, for
example with the missing temporal filter.

The 52N SOS supports the OGC Sensor Observation Service 2.0 Hydrology
Profile but it is not enabled by default.

Here you find a description how to enable the OGC Sensor Observation
Service 2.0 Hydrology Profile in the 52N SOS:

https://wiki.52north.org/bin/view/SensorWeb/SosProfiling

> Two thoughts that came to mind are:
>
>  - There is a configuration option - perhaps "Maximum number of returned
> observation values" that I missed

That is an additional setting to reduce the size of the returned
observations.

>   - Entering the data through the ResultTemplate is somehow making SOS think
> the time series is a single observation

That is the idea of the result handling operations, insert or retrieve
measurements without the complete observation metadata (form OGC SOS 2.0
Spec: "...inserting sensor results into an SOS without the need to
repeatedly transmit the complete set of observation metadata.")

The values of an InsertResult operation are single measurements which
are inserted as single observations into the SOS.

Best,
Carsten
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Re: GetObservation with no temporal filter returning too many values

TSlawecki
Thank you again - this makes sense.