ADCP Toolbox Version 5.0
Frequently Asked Questions
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Topics
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How
do I get my data into MATLAB?
In this package is an m-file called
rdi2cdf. It is a stand alone function which converts the
RDI ADCP broadband or workhorse data format to NetCDF. I
will not go into the advantages of NetCDF here, see for
yourself at UNIDATA.
Once in NetCDF format, data can be ported into MATLAB wholly
or in part, using the Mex-file
gateway. Rdi2cdf uses to the Mex-file gateway
to do the conversion. The NetCDF
Toolbox makes useage of the Mex-file gateway more user
friendly, and is required to view your data using the scripts
presented here.
Attached is a listing of a typical
ADCP NetCDF file header. The
header file shows how the ADCP data is stored in NetCDF,
including the dimensions, variables, attributes, and global
attributes. The header file
shown here is from the raw NetCDF file created from the
Demo ADCP Data.
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How
do I view my data in MATLAB?
There are three viewers that have
been developed to allow the user to display the ADCP data
in NetCDF format. These viewers are the Star* suite of toolboxes
developed by the US Geological Survey. Starbeam is used
to view the data in non-EPIC format, Starbare is used to
edit bad data points, and Starbuck displays the Best Basic
Version (BBV) of the data with EPIC variables. Each Star*
program is not only a function, but a folder of programs
(or toolbox) that are required to run the viewers. These
viewers are included in the NetCDF
Toolbox, which is required to run the ADCP
Toolbox. Detailed information regarding the Star* viewers
can be found in the online version of the ADCP
Data Processing System Manual.
The ADCP data can also be viewed
in a browser called ncbrowser, which is included in the
NetCDF
Toolbox. Ncbrowser allows the user to easily view the
dimensions, variables, and attributes of the ADCP file.
(Click here to see an example of the ncbrowser
window.) Detailed information regarding ncbrowser can
be found within MATLAB after the NetCDF Toolbox has been
installed, by typing help ncbrowser in the command window.
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Where can I
find the old ADCP tools for MATLAB 4.0?
I am no longer actively supporting them, and there are some
bugs which have been eliminated in the latest version for
MATLAB 5.0, but you can still download them here.
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Why isn't Rdi2cdf working?
Are you on a Sun workstation? Rodolphe Rousselet (rous@shom.fr)
of EPSHOM - France has contributed a patch that should eliminate
fread problems on Sun workstations, download my_fread.m, a
new version of fread.m.
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Will
rdi2cdf.m work on my narrowband data?
No. However, there are enough narrowband users out there who
seem to like this concept that I have already heard from some
folks interested in porting the code. Let me know if you want
to help, and can put everyone in touch with one another.
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Why
don't the beam to earth conversions exactly match BBLIST output?
For data recorded in beam format: The beam2earth function
does not yet include transducer and compass calibration adjustments.
The conversion from beam to earth agrees within 1.18 mm/s
with BBLIST output.
If your data was recorded in earth coordinates, you have
nothing to worry about (if the compass and tilt sensors
did their jobs well).
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Where is my bottom
ping data?
Since this code was originally written for bottom mounted,
long term, time-series measurements, bottom ping data is ignored.
The code doesn't seem to choke on data with bottom pings,
but since our work is mostly self contained, we can't be sure.
We are starting to work with bottom ping data so we rewrite
the code to read in bottom ping data in the future.
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How
accurate is the Beam to Earth rotation algorithm?
Accurate enough to provide a general idea if the instrument
is working correctly. I would not recommend using it
for scientific analysis at this time because it does not use
beam mapping and does not make use of the transducer calibration
matrix.
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