{"action":"created","issue":{"url":"https://api.github.com/repos/obspy/obspy/issues/1053","labels_url":"https://api.github.com/repos/obspy/obspy/issues/1053/labels{/name}","comments_url":"https://api.github.com/repos/obspy/obspy/issues/1053/comments","events_url":"https://api.github.com/repos/obspy/obspy/issues/1053/events","html_url":"https://github.com/obspy/obspy/issues/1053","id":78124130,"number":1053,"title":"obspy.station.response.PolesZerosResponseStage requires at least 1 pole and 1 zero","user":{"login":"paitor","id":12034761,"avatar_url":"https://avatars.githubusercontent.com/u/12034761?v=3","gravatar_id":"","url":"https://api.github.com/users/paitor","html_url":"https://github.com/paitor","followers_url":"https://api.github.com/users/paitor/followers","following_url":"https://api.github.com/users/paitor/following{/other_user}","gists_url":"https://api.github.com/users/paitor/gists{/gist_id}","starred_url":"https://api.github.com/users/paitor/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/paitor/subscriptions","organizations_url":"https://api.github.com/users/paitor/orgs","repos_url":"https://api.github.com/users/paitor/repos","events_url":"https://api.github.com/users/paitor/events{/privacy}","received_events_url":"https://api.github.com/users/paitor/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":1,"created_at":"2015-05-19T14:59:34Z","updated_at":"2015-05-19T15:20:33Z","closed_at":null,"body":"Hi \r\n\r\nIf I understand the definition of the class obspy.station.response.PolesZerosResponseStage correctly the current implementation requires at least one pole and one zero upon initiation of a new object of this class. This is according to my understanding of the poles and zeros type of transfer function not necessary requirement and neither a requirement of the FDSN station XML and should therefore probably be changed.\r\n\r\nregP"},"comment":{"url":"https://api.github.com/repos/obspy/obspy/issues/comments/103546946","html_url":"https://github.com/obspy/obspy/issues/1053#issuecomment-103546946","issue_url":"https://api.github.com/repos/obspy/obspy/issues/1053","id":103546946,"user":{"login":"krischer","id":800487,"avatar_url":"https://avatars.githubusercontent.com/u/800487?v=3","gravatar_id":"","url":"https://api.github.com/users/krischer","html_url":"https://github.com/krischer","followers_url":"https://api.github.com/users/krischer/followers","following_url":"https://api.github.com/users/krischer/following{/other_user}","gists_url":"https://api.github.com/users/krischer/gists{/gist_id}","starred_url":"https://api.github.com/users/krischer/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/krischer/subscriptions","organizations_url":"https://api.github.com/users/krischer/orgs","repos_url":"https://api.github.com/users/krischer/repos","events_url":"https://api.github.com/users/krischer/events{/privacy}","received_events_url":"https://api.github.com/users/krischer/received_events","type":"User","site_admin":false},"created_at":"2015-05-19T15:20:33Z","updated_at":"2015-05-19T15:20:33Z","body":"Can you just pass empty lists. At least initialization works. I did not test if you can actually calculate a response with it thou.\r\n\r\n```python\r\nIn [1]: from obspy.station.response import PolesZerosResponseStage\r\n\r\nIn [2]: PolesZerosResponseStage(stage_sequence_number=1, stage_gain=1E6, \r\n    stage_gain_frequency=1.0, input_units=\"counts\", output_units=\"m/s\", \r\n    pz_transfer_function_type=\"LAPLACE (RADIANS/SECOND)\", normalization_frequency=2.0, \r\n    zeros=[], poles=[])\r\nOut[2]:\r\nResponse type: PolesZerosResponseStage, Stage Sequence Number: 1\r\n\tFrom counts to m/s\r\n\tStage gain: 1000000.0, defined at 1.00 Hz\r\n\tTransfer function type: LAPLACE (RADIANS/SECOND)\r\n\tNormalization factor: 1, Normalization frequency: 2.00 Hz\r\n\tPoles:\r\n\tZeros:\r\n```"}}