[webservices] ws-station and obviously wrong sensitivity

[Doug Neuhauser]

I believe the way we handle this for "unknown" sensors or
calibration info is to represent the full SEED output
with an overall sensitivity of 1.  This way it is obvious to
users that we cannot provide a known velocity sensitivity.
However, the user loses the knowledge that this may be a
velocity sensor.

- Doug N

On 05/11/11 13:25, Chad Trabant wrote:
>
> Hi Philip,
>
> The "obviously wrong" is the sticky part that's usually impossible to quantify and generalize.  As I'm sure you known, the root of this particular problem is that SEED does not have any way to mark values as "unknown" or null, for required fields this means filling in something bogus.  ws-station is not the appropriate place to be making judgements of the validity of response information, in general ws-station returns what's in the database.  In your response information for CSB the sensitivity for the sensor is set to 1, we wouldn't be comfortable filtering out responses based solely on that, some of them might be correct!
>
> In the future, if we SEED standard adopts some way to represent unknown values or similar I can see us filtering stuff, we need good documented rules though.  For now problems like these are much better addressed upstream in my opinion.
>
> Chad
>
> On May 11, 2011, at 9:21 AM, Philip Crotwell wrote:
>
>> Hi
>>
>> One of our stations has an "unknown" sensor. I know that sounds weird,
>> but it is old, 50 meters down a borehole backfilled with concrete and
>> no records left from the installation. So, in order to get the data to
>> the archive, we had to submit dataless where the response was filled
>> in, but in a way that says "we don't know". Mary said that the correct
>> way to do this was a unity gain blockette53 with no poles or zeros. If
>> you have the full response, this is a pretty noticeable oddball. But
>> in the channel level of the station web service, you get just the
>> overall sensitivity. It is probably still relative clear that this is
>> bogus, but not quite as clear as it is the 1 from the sensor combined
>> with the actual gain from the digitizer, so you get something like
>> 629129.0 for the sensitivity. As this appears to be somewhat of a
>> standard, it might be better if the station web service could tell the
>> difference between this type of "syntactically correct, but obviously
>> wrong" response and just not publish a value for those stations to
>> avoid sending out wrong values.
>>
>> If you are interested, the stations with this issue from our network
>> are CO.CSB and CO.RGR.
>>
>> thanks,
>> Philip
>> _______________________________________________
>> webservices mailing list
>> webservices at iris.washington.edu
>> http://www.iris.washington.edu/mailman/listinfo/webservices
>
>
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-- 
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Doug Neuhauser                  University of California, Berkeley
doug at seismo.berkeley.edu        Berkeley Seismological Laboratory
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