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iris-edu / mseed3-evaluation

A repository for technical evaluation and implementation of potential next generation miniSEED formats
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Maximum length of FDSN Identifiers #5

Closed krischer closed 7 years ago

krischer commented 7 years ago

Discussion branched off #2. Concerns DRAFT20170622.

@krischer

Why are the maximum lengths of all the FDSN identifiers still kind of short? If we allow for fairly long time series identifiers, why not also give more space to the identifiers?

@chad-iris

Practical reasons. These identifiers are in each record, lots of redundancy. In our domain, folks are used to "reading" or "saying" the identifiers, where concise is valuable. The current lengths are designed to fit the future needs we can see, 8 character networks can be much more meaningful (can include 4 character years for temporary networks), station code hasn't been a problem, location holds what is needed to identify nodes in arrays of 100,000's of sensors and channel now has room for a lot more instrument identifiers. In a way, it's now double the address space.

Also, in the future we can decide on a new namespace for identifiers, e.g. "FDSN2:", and come up with expanded or completely new schemes. This variable length identifier concept is one of the best changes we've discussed in next general miniSEED in my opinion. Provides a lot of future proof-ness.

This question needs to be turned around, why should we give the identifiers more space?

krischer commented 7 years ago

This question needs to be turned around, why should we give the identifiers more space?

All good points and I largely agree. I guess one can make an argument for longer station + location codes. Assuming my proposal for dashes and underscores in the identifiers is accepted, one could then arrange sensors in a grid with a location code/id of for example G_29_2303 (geophone, line 29, sensor 2303 - this is now only 9 characters but you get the point).

chad-earthscope commented 7 years ago

Assuming my proposal for dashes and underscores in the identifiers is accepted, one could then arrange sensors in a grid with a location code/id of for example G_29_2303 (geophone, line 29, sensor 2303 - this is now only 9 characters but you get the point).

FWIW, you shouldn't need the G for geophone as that characteristic is identified in the channel.

chad-earthscope commented 7 years ago

In DRAFT 20170708 network, station, location fields can be up to 8 characters. This is easily changed before any final version is adopted and it will likely be discussed further as the audience widens.