deconvolution with obspy - using non laplace dataless file ??

Users Mailing List Archive
1

Dear All,

I am trying to process mseed data using dataless seed files that are obviously coded in frequency rather than in laplace transform.

Obspy cannot stand with such non laplace dataless files.

I assume that there is somewhere a 2.PI() factor that as to be apply to convert the laplace in freq (if I am right), but where ?

As this laplace/frequency encoding should be tagged somewhere in the dataless file, could it be possible to make obpsy automatically detected and convert the dataless encoding format ?

At least, Does anybody knows how to convert my frequency coded dataless to laplace dataless files ? Is there any standard scripts ?

Thanks in advance
Best regards
Mickael.

2

Hi Mickael,

there's work in progress on what you're encountering:
https://github.com/obspy/obspy/pull/899

One other thing you could do for a quick fix is to convert your dataless
to StationXML using IRIS's tool
(https://seiscode.iris.washington.edu/projects/stationxml-converter/wiki) and
then go via..
  .. read_inventory(..)
  .. stream.attach_response(..)
  .. stream.remove_response(..)
essentially going via evalresp.

best,
Tobias

3

Thanks Tobias,

I will try the solution using stationXml.

Regards
Mickael.

Mickaël LANGLAIS

4

hi
I have done a pull request to add this feature
you can have a look here.

https://github.com/obspy/obspy/pull/899

Travis process failed on this patch because the branch I have used, have a something broken on quakeml
(so nothing related to laplace)

Reagrds
Marc

5

Hi Tobias,

Trying to use your solution, but I am facing an error...

Traceback (most recent call last):
   File "td2a_deconvolution.py", line 33, in <module>
INV=read_inventory("/home/langlami/temp/data-stpaulubaye/SURF.xml")
   File "/home/langlami/anaconda/lib/python2.7/site-packages/obspy/station/inventory.py", line 38, in read_inventory
     return _readFromPlugin("inventory", path_or_file_object, format=format)[0]
   File "/home/langlami/anaconda/lib/python2.7/site-packages/obspy/core/util/base.py", line 321, in _readFromPlugin
     raise TypeError('Unknown format for file %s' % filename)
TypeError: Unknown format for file /home/langlami/temp/data-stpaulubaye/SURF.xml

Does the xml file can stand multiple channels ?

Should I add the format when invoking read_inventory fonction ? But which one ?

Thanks,
Mickael.

Mickaël LANGLAIS

6

Hi Mickael,

ObsPy currently uses the StationXML XSD scheme to check if a file is a StationXML file. Many StationXML files out there are strictly speaking not valid StationXML files…
I guess we should also change our format detection algorithm a bit in that regard.

Just force the format (as you already suggested) with

INV=read_inventory("/home/langlami/temp/data-stpaulubaye/SURF.xml”, format=“stationxml”)

That will skip the format detection routines and jump straight to the file parsing stage.

Cheers!

Lion