[webservices] A question of location ID, how to represent empty IDs in XML?

[Joachim Saul]

Hi Philip,

Philip Crotwell wrote on 07/31/2014 02:59 PM:
>http://www.iris.edu/ds/newsletter/vol1/no1/specification-of-seismograms-the-location-identifier/
>
> From this it seems that  location id was intended to be exactly 2
> characters, not zero or two. My feeling is that we have a long
> tradition of the location id being "space-space" and not null or
> empty. Personally I really dislike space-space, but the only thing I
> dislike more than space-space is empty.

Now we have the above IRIS newsletter article vs. the FDSN standard. 
Which one should be considered authoritative?

Philip Crotwell wrote on 07/31/2014 01:18 PM:
> Just another data point, Earthworm, which is widely used by regional
> networks globally, has long had the "dash dash is the same as space
> space" convention. So dash dash is not something pulled out of thin
> air, it is how at least I do things already.

OK, at least we know now where Chad and you got that idea from. ;)

> And this shows that it is fairly common (if not technically correct)
> for users to regard space-space as the location id instead of
> regarding it as null with 2 spaces for padding. My guess is that very
> few users are aware of this, and even as someone who has been writing
> seismic software for a couple of decades I still think of the location
> id as space-space, not null.
>
> http://www.isti2.com/ew/PROGRAMMER/location_codes/EW_Loc_policy.txt

If you say Earthworm I say SAC. The location code in SAC is trimmed just 
like in other software already mentioned. Does that convince you? Of 
course not, as we are here discussing neither Earthworm nor SAC channel 
naming convention.

This discussion is about FDSN standard channel naming. Obviously neither 
Earthworm nor SAC count. Both use their own formats and within their 
respective ecosystems they can of course represent the location code in 
whatever way is considered appropriate, as long as the export to FDSN 
formats is done properly.

Cheers
Joachim