CODAS FAQ

As much as possible, this FAQ answers with links to the documentation.


What is CODAS processing (what does it do?)

  • See this introduction to

ADCP processing and CODAS processing

  • In addition to the present documentation, there is a somewhat outdated but very detailed postscript manual.

What software do I need to get started?

You will need several different programs, as well as software from the UH ADCP group. Installation instructions are here.

How hard will this be? Will it take long to learn?

It depends on your background, but the short answer is: ‘yes, it will take some time to learn, but less time than it would take to write your own code’.

Longer answer:

That depends on many factors, including

  • how well you know your computer (the commandline interface, how to configure the paths and environment variables)
  • how good your dataset is (does it have clock problems? navigation problems?)
  • the manner in which the heading correction (to the gyro) will be calculated (pingdata with ue4 is easy, LTA is hard)

After setting up the computer, it really depends on the data. It could be days or weeks.

I am familiar with CODAS processing. How do I get started on quick_adcp.py?

For someone already familiar with CODAS processing steps, you can read the section on CODAS Processing and try an example

Can I get this documentation for off-line use?

This documentation is available in the file adcp_doc.zip, located here

If you are about to leave, and you want to be able to run CODAS processing off line, you should plan to install and test all the necessary programs before you leave. Follow these instructions to ensure that CODAS setup and processing documentation is accessible on your computer.

If all you want to do is look at UHDAS data at sea, check this link to see what kinds of data are available.

What are my options for plots of the ocean currents during a cruise?

That depends on the instrument and data acquisition system used on your cruise.

  • If you have UHDAS, look at this section

  • Otherwise, you probably have VmDAS, and can

    • process the data (you should install everything before you go)
    • read the files directly using matlab or python (read the notes: requires some or all CODAS and supporting programs to be installed)

I have distribution disk full of UHDAS data from a cruise. What is on it? How can I look at the data?

This link gives an introduction to the data in a UHDAS cruise directory.

Please read about CODAS conventions (eg. decimal day is zero-based)

Note

The database has undergone preliminary processing, but steps remain to ensure there are no calibration errors, gaps, or bad profiles.

I have a dataset from a Workhorse already processed but I learned I may be able to see more bins at the bottom. How do I do that?

Several years ago, a bug was discovered wherein the blanking over the bottom due to side-lobe reflection was hardwired to expect beams with 30degrees. This has been updated in the Mercurial repositories as of May 1, 2009.

An ADCP with 30deg beams can only use 85% of the water column when the bottom is in range, but with 20deg beams the useful data range is more like 95% of the total.

It is not hard to reset the bottom-masking flags. Explanations and prescriptions are here. See Unediting Scenarios.