obspy/obspy — pull request #641 by megies (2013-09-30 15:47:54+00:00)
Title: STA2 header line of GSE2 files

The GSE2 manual defines a (mandatory! see [pdf](https://github.com/obspy/obspy/blob/master/obspy/gse2/docs/provisional_GSE2.1.pdf) page 66, table 6) second header line that we currently do not parse (and also *do not write*!). Besides the *network code* (albeit possibly SEED-non-conform 9 chars long), it can contain other useful information, namely *station coordinates*:
```
Position Name Format Description
1-4 "STA2" a4 Must be "STA2"
6-14 Network a9 Network identifier
16-34 Lat f9.5 Latitude (degrees, S is negative)
36-45 Lon f10.5 Longitude (degrees, W is negative)
47-58 Coordsys a12 Reference coordinate system (e.g., WGS-84)
60-64 Elev f5.3 Elevation (km)
66-70 Edepth f5.3 Emplacement depth (km)
```
In principle we should definitively parse that information.. the problem is that I have seen data from two different sources and both do not adhere to the exact positioning as given in the manual, see e.g. [one of our test files](https://github.com/obspy/obspy/blob/master/obspy/gse2/tests/data/loc_RNON20040609200559.z):
```
STA2 -999.0000 -999.00000 -.999 -.999
```
For example the longitude field goes from 26-35.
A header from another file I saw looks like this (numbers changed):
```
STA2 ABCD 12.34567 1.23456 WGS-84 -123.456 1.234
```

So, to sum it up, currently we are potentially missing useful header information when reading from GSE2. But on the other hand, the data out there seems to not adhere to the official manual. So I am not sure what to do about it.