[data-issues] UW.LON bad compression

[Philip Crotwell]

My understanding is that in cases where there is no B1000, the DHI  
server gets the compression type from the oracle database. That can  
be troublesome as sometimes the data in the archive and that in the  
pond are not the same, like the issue with the ongoing USNSN  
recompression.

Philip

On May 18, 2006, at 4:16 PM, Chad wrote:

>
> Just my 2 cents.  Something is definitely wrong with that  
> particular data.
> The miniSEED records that I looked at did not have any indication  
> of their
> encoding format as there are no 1000 blockettes.  I tried to  
> decompress the
> data as 16/32-bit ints, 32/64-bit floats, Steim-1 and Steim-2.   
> None of those
> produced anything that looked like real data.  So the data is  
> either badly
> packed/compressed or in a different encoding (24-bit ints?)
>
> Many of the DMC tools default to Steim-1 when no encoding is  
> indicated.  Maybe
> something Philip is using is defaulting to 32-bit floats?
>
> Chad
>
> Philip Crotwell wrote:
>> Hi
>>
>> For UW.LON in the POND for this event, I get an error that looks like
>> the data is either badly compressed, or has the wrong compression  
>> type.
>> The mseed record thinks it is 32 bit floats, but there are not enough
>> bytes for the number of points in the record. Other events for this
>> station might have this same problem, I haven't looked.
>>
>> When I try to look at this in wilber, I get an error of "Unable to
>> generate plots at this time. Sorry." for this station, so your wilber
>> plot generator is probably seeing the same issue.
>>
>> This is via DHI, but I suspect the problem is in the underlying data,
>> not the server.
>>
>> thanks,
>> Philip
>>
>> Event: Komandorskiye Ostrova Region | 10/20/1992 04:40:02 GMT |  
>> Mag: 5.5
>> | Depth 33.00 km | (55.525, 166.429)
>>
>> UW.19630301T00:00:00.000Z.LON.  .BHZ.19920601T00:00:00.000Z Data
>> retrieval in progress
>> java.lang.IllegalArgumentException: Not enough bytes for 2014 32 bit
>> data points, only 4036 bytes.
>>         at edu.iris.dmc.seedcodec.Codec.decompress(Codec.java:73)
>>         at
>> edu.iris.Fissures.seismogramDC.LocalSeismogramImpl.decodeBits 
>> (LocalSeismogramImpl.java:1398)
>>
>>         at
>> edu.iris.Fissures.seismogramDC.LocalSeismogramImpl.get_as_longs 
>> (LocalSeismogramImpl.java:1053)
>>
>>         at edu.sc.seis.fissuresUtil.bag.Cut.cut(Cut.java:59)
>>
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>