Problem description: Axivity (axivity.com/userguides/ax3/using/) watch device logs data internally in a binary packed format. This format is named Continuous Wave Accelerometer (CWA) format. This format is very efficient for storing large amounts of data but is not natively supported by many applications. I use GGIR library from R to read the CWA file.

I have a requirement to generate 25 CWA files to be loaded in to a database. I can either ask 25 users to wear it on the device on their wrist for 2 weeks to generate the 2-week long log data in CWA format. Or I can use one CWA file that I have and change its header and save it as CWA file thereby creating 25 clones. But R can read it but not save it as CWA. I could not glean much out of http://axivity.com/help/21 to do this reinterpolation. Is there a way to edit CWA files and save them back to the same format by any other method like PERL? A test data set is available here axivity.com/downloads/ax3 (AX3 example Data). Thanks.

  • 1
    The GGIR source code is available on GitHub - the easiest way to understand the format will be to read that code. But it might still be simpler to contact someone who's published research using GGIR to ask if you can borrow their datasets, or just beg / pay colleagues, students etc. to wear the devices for two weeks.
    – Rup
    Aug 2 '17 at 20:52

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