4.3.3.2.2. Using Python to read single-ping ADCP dataΒΆ

Multiread read single-ping ADCP data

  • access to single-ping ADCP data

  • ancillary data (heading, navigation) depends on data type:

    • UHDAS *.raw, VmDAS ENR (beam coordinates, no navigation)

    • VmDAS *.ENS (beam coordinates, NO navigation)

    • VmDAS *.ENX (earth coordinates, with navigation)

    • VmDAS *.STA, *.LTA (earth coordinates, with navigation, averaged)

From within an ipython session or a python program:

from pycurrents.adcp.rdiraw import Multiread
m=Multiread(filelist_or_wildcard, instrument)
data=m.read(args)

where

  • filelist_or_wildcard is

    • a string with a wildcard representation of the files, eg '/home/data/current_cruise/raw/wh300/*.raw'

    • a string with a single file, or a list of files obtained in some manner

  • instrument is a 2-letter string representing the instrument: 'nb', 'os', 'wh'

example:

from pycurrents.adcp.rdiraw import Multiread
m=Multiread('km2013_331*.raw','os')
data=m.read(step=30)

example:

from pycurrents.adcp.rdiraw import Multiread
m=Multiread('*.LTA','os')
data=m.read()

To read a single UHDAS file and get ocean currents, try uhdasfile. This module requires that the complete UHDAS cruise directory be intact. It uses the raw file to infer where the gbins are, and creates ocean velocities using the positions and heading that were specified during the original processing. These velocities use the heading from the reliable (put possibly inaccurate) device so shears should be fine but the velocities may have errors. This is the python equivalent of get_xfraw.m in matlab. It only works for modern datasets collected (or reprocessed) with Python CODAS.

example:

from pycurrents.adcp import reader
data=reader.uhdasfile('raw/os75/tt2013_115_36000.raw',
                       inst='os',
                       h_align=58.9)