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dolfyn.rotate.rst

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Rotate Functions

Contains functions for rotating data through frames of reference (FoR):

  1. 'beam': Follows the acoustic beam FoR, where velocity data is organized by beam number 1-3 or 1-4.
  2. 'inst': The instrument's XYZ Cartesian directions. For ADVs, this orientation is from the mark on the ADV body/battery canister, not the sensor head. For TRDI 4-beam instruments, the fourth velocity term is the error velocity (aka XYZE). For Nortek 4-beam instruments, this is XYZ1 Z2, where E=Z2-Z1.
  3. 'earth': East North UP (ENU) FoR. Based on either magnetic or true North, depending on whether or not DOLfYN has a magnetic declination associated with the dataset. Instruments do not internally record magnetic declination, unless it has been supplied via external software like TRDI's VMDAS.
  4. 'principal': Rotates velocity data into a streamwise, cross-stream, and vertical FoR based on the principal flow direction. One must calculate principal heading first.

~dolfyn.rotate.api.rotate2 ~dolfyn.rotate.api.set_declination ~dolfyn.rotate.api.calc_principal_heading ~dolfyn.rotate.api.set_inst2head_rotmat ~dolfyn.rotate.base.euler2orient ~dolfyn.rotate.base.orient2euler ~dolfyn.rotate.base.quaternion2orient ~dolfyn.rotate.base.calc_tilt

These functions pertain to both ADCPs and ADVs:

>> import dolfyn
>> dat = dolfyn.read_example('burst_mode01.VEC')

>> dolfyn.set_declination(dat, 12)
>> dolfyn.rotate2(dat, 'earth')

>> dat.attrs['principal_heading'] = dolfyn.calc_principal_heading(dat['vel'])
>> dolfyn.rotate2(dat, 'principal')

dolfyn.rotate.api

dolfyn.rotate.base