Response is dropping stationxml decimation element

Usage Questions
1

I have a test StationXML file that is part of the IRIS validation test suite.
It contains a response with this stage in it:

<Stage number="1">
    <Decimation>
        <InputSampleRate>512000.0</InputSampleRate>
        <Factor>1</Factor>
        <Offset>0</Offset>
        <Delay>0.0</Delay>
        <Correction>0.0</Correction>
    </Decimation>
    <StageGain>
        <Value>0.4</Value>
        <Frequency>1.0</Frequency>
    </StageGain>
</Stage>

This stage does not specify a PolesZeros/Coefficients/etc element; it
is designed to fail IRIS validation rule 423.
Obspy reads this stage into a generic ResponseStage but it drops the decimation
information (e.g., stage.decimation_input_sample_rate is None), making it look like any other stage containing only a stage.stage_gain.

Is this a bug ?

I’ll attach the xmlfile to this post.

Thanks!
F1_423.xml (30.0 KB)

2

Nevermind - looking through the code I can see that it expects a stage
to be one of the 5 types:
type_elems = [poles_zeros_elem, coefficients_elem, response_list_elem,
fir_elem, polynomial_elem]

and for these it will pass the decimation info in **kwargs to instantiate the object,
or else it simply returns the base ResponseStage without any additional info (like decimation).

So I guess I’ll have to trap this particular case using lxml directly.