results in text format: empty location code should be represented by -- #38
Description
This observations is being done on the INGV instance of the service, version 1.0.3.
I believe the results in the default format, i.e. text should translate occurences of empty location codes, i.e. '' to '--' in the output. This seems not to be done in the specified version of the service.
The FDSN specs are not very explicit on this detail. The replacement is mentioned explicitly only in the context of POST requests. However, the provided examples include this replacement '' -> '--', and it actually does not really make much sense otherwise as parsing would become impossible (So we also might want to report also against the specs for more clarity). Also the IRIS implementations does this replacement. The replacement does not apply for the other output formats as can be seen from the other examples.
Example from the specs (page 7, https://fdsn.org/webservices/fdsnws-availability-1.0.pdf):
Requesting extents in default ‘text’ format with all extra columns:
#Network Station Location Channel Quality SampleRate Earliest Latest Updated TimeSpans Restriction
IU ANMO -- BHZ M 20.0 1989-08-29T22:07:20.482000Z 1998-10-26T17:38:43.640000Z 2018-05-08T21:47:09Z 611 OPEN
IU ANMO 00 BHZ M 0.0 2002-08-28T18:17:51.000000Z 2008-05-23T23:09:24.000000Z 2017-12-06T03:42:35Z 9051 OPEN
IU ANMO 00 BHZ M 20.0 1998-10-26T20:35:58.310000Z 2018-07-09T20:45:47.369000Z 2018-07-10T08:29:54Z 2238 OPEN
IU ANMO 00 BHZ M 40.0 2018-07-09T20:46:40.594000Z 2019-02-04T23:59:59.994000Z 2019-02-05T09:27:24Z 1 OPEN
IU ANMO 10 BHZ M 0.0 2002-11-28T04:00:00.000000Z 2007-06-01T19:29:00.000000Z 2017-12-06T03:09:51Z 47 OPEN
IU ANMO 10 BHZ M 40.0 1998-10-26T20:35:59.072000Z 2019-02-04T23:59:59.994000Z 2019-02-05T09:27:24Z
Evidence of the problem (in comparison of IRIS output):
method: extent
#Network Station Location Channel Quality SampleRate Earliest Latest Updated TimeSpans Restriction
AC TPE HHE D 100.0 2013-01-24T15:20:57.500000Z 2014-06-10T00:00:00.000000Z 2017-07-01T03:41:38Z 57421 OPEN
AC TPE HHN D 100.0 2013-01-24T15:21:22.460000Z 2014-06-10T00:00:00.000000Z 2017-07-01T02:25:12Z 57432 OPEN
AC TPE HHZ D 100.0 2013-01-24T15:20:56.570000Z 2014-06-10T00:00:00.000000Z 2017-07-01T04:24:22Z 54902 OPEN
AC TPE 00 HHE D 100.0 2024-12-16T12:38:32.170000Z 2025-04-08T00:00:00.000000Z 2025-04-09T02:01:57Z 1 OPEN
AC TPE 00 HHN D 100.0 2024-12-16T12:38:32.180000Z 2025-04-09T00:00:00.000000Z 2025-04-09T19:11:32Z 2 OPEN
AC TPE 00 HHZ D 100.0 2024-12-16T12:38:31.910000Z 2025-04-09T00:00:00.000000Z 2025-04-09T16:11:00Z 1 OPEN
#Network Station Location Channel Quality SampleRate Earliest Latest Updated TimeSpans Restriction
AC TPE -- HHE M 100.0 2013-02-13T19:44:43.000000Z 2014-06-10T13:36:48.150000Z 2017-04-07T20:53:20Z 91371 OPEN
AC TPE -- HHN M 100.0 2013-02-13T19:44:43.170000Z 2014-06-10T13:36:49.330000Z 2017-04-07T20:53:20Z 91421 OPEN
AC TPE -- HHZ M 100.0 2013-02-13T19:44:43.240000Z 2014-06-10T13:36:49.320000Z 2017-04-07T20:53:20Z 87195 OPEN
method: query
#Network Station Location Channel Quality SampleRate Earliest Latest
AC TPE HHE D 100.0 2013-01-24T15:20:57.500000Z 2013-01-24T15:20:57.590000Z
AC TPE HHE D 100.0 2013-01-24T15:20:59.030000Z 2013-01-25T00:00:00.000000Z
AC TPE HHE D 100.0 2013-01-25T00:00:00.000000Z 2013-01-25T10:39:20.760000Z
[...]
#Network Station Location Channel Quality SampleRate Earliest Latest
AC TPE -- HHE M 100.0 2013-02-13T19:44:43.000000Z 2013-02-13T19:47:22.990000Z
AC TPE -- HHE M 100.0 2013-02-13T19:48:03.360000Z 2013-02-13T22:28:01.130000Z
AC TPE -- HHE M 100.0 2013-02-13T22:28:08.340000Z 2013-02-13T23:06:37.950000Z
[...]