crash on "-nan" ClockDrift

[RJSLA]

The convertor dies when encountering "-nan" as the value for ClockDrift in StationXML. This results from automated StationXML creation software at fdsnws sites (such as SeisComP) when samplerate is given as 0. I have requested that the authors of SeisComP address the issue on their end, but there is no guarantee that that will resolve every case, especially if fdsnws operators are slow to update their software.
I suggest the convertor treat ClockDrift as 0 if it is found as anything other than a number.
Here's the error report:
dies with java.lang.NullPointerException
at edu.iris.dmc.seed.control.station.B052.setMaxClockDrift(B052.java:194)
Here is an example fdsnws request that will generate the problem:
https://www.orfeus-eu.org/fdsnws/station/1/query?format=xml&level=response&nodata=404&channel=*&network=OE&station=ABTA
Thanks.

[timronan]

ClockDrift is a double type according to the StationXML schema [clockdrift] "-nan" is not a valid double value. The example document is not stationxml schema compliant. The SeisComP developers should consider excluding the optional ClockDrift field rather than generating an invalid stationxml document.

We will discuss adding this enhancement in the next stationxml-seed-converter release. Thank you for posting this issue.

[RJSLA]

Thanks for checking that. I did not check first if '-nan' was a valid XML double, and I now see it is not, only 'NaN' would be. Therefore, it looks like SeisComP not only produced an unhelpful ClockDrift, but failed to render NaN correctly. However, neither '-nan' nor 'NaN' is helpful as a ClockDrift value. The developers of SeisComP did tell me they would address that general issue, but I did not specifically ask about '-nan' vs 'NaN'.

[timronan]

Thanks for this additional information. Let us know if the SeisComP developers get to this issue. I will keep you updated on future stationxml-seed-converter releases.

[RJSLA]

I received this from Jan Becker:
The StationXML standard even required ClockDrift to be >= 0 if set. I have fixed the issue in SeisComP and an invalid ClockDrift will be omitted from the XML.

Of course, it may be some time before network and data center operators update SeisComP at their sites.