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Reading Current Data .aqd in MATLAB

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    Ellie Best

    Hi Kritika, thank you for posting in the Nortek forum!

    The .aqd file is the raw binary data that is collected by the Aquadopp, so this cannot be read into Matlab. The .dat file is simply numeric ASCII data, so you should be able to read this into Matlab as a matrix using the Import Data function. The .hdr file describes the contents of the .dat file, so you will know which columns correspond to which data type, and pull them out of the matrix as required.

    Please let me know if you have any more problems with getting the data into Matlab.

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    Kritika Valluri

    Thank you, Ellie! It worked.

    I wanted to know, is there a reason the measured sound speed would be the same value throughout depth? The depth and temperature changes but the sound speed doesn't. 

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    Ellie Best

    I'm glad to hear it! :)

    There are two options for sound speed value, you can either calculate the sound speed using the temperature measured at the head of the instrument, or you can use a fixed sound speed value which is used for the entire deployment. If the sound speed isn't changing when the temperature does, it's possible that the deployment was set up with a fixed sound speed.

    You can check this in the .hdr file; in the first section you will find a line with "Sound Speed" that will state "FIXED" or "MEASURED".

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    Kritika Valluri

    Oh, I see. That column next to 'Sound Speed' states 'User Specified'. I believe that is the same thing as FIXED, right?

    Thank you!

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    Ellie Best

    Yep, that will be the same thing as FIXED. No problem!

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