CODAS FAQ

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


How do I access ADCP data (CODAS, VmDAS LTA or ENX)?

Different data types have support via Matlab or Python. Check this link

How can I tell if the heading messages are good?

There are pages in the documentation describing most of the serial heading messages UHDAS acquires that have a quality indicator. Check the ` Troubleshooting ../Troubleshooting/ashtech_diagnostics.html section.

What is CODAS processing (what does it do?)

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.

My computer is all set up, but I am new to ADCP data processing. Where should I start?

Read the section on CODAS Processing . Work you way through the examples to get the background for your case.

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

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?

Read the section on CODAS Processing . Work you way through the examples to get the background for your case.

Can I get this documentation for off-line use?

This documentation is available in the file adcp_doc.zip – the link is this page

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. By far, the easiest way to do this is to

  1. install Virtual Box
  2. download the Virtual Computer, and import it.

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.

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

Look at the documentation page called Accessing ADCP data, Get familiar with the UHDAS cruise directory structure, and be aware of 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 DVD full of UHDAS data from a cruise. How do I finish processing the data?

You must have a computer with a working CODAS processing installation. Follow these instructions to ensure that CODAS processing software is set up on your computer. By far, the easiest way to do this is to choose the Virtual Computer strategy. Then you should read about CODAS Processing and work you way through the post-processing example.

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.

I am getting a Basemap error with gautoedit. How do I fix it?

If you have a long Traceback that ends like this:

File "/usr/lib/pymodules/python2.7/mpl_toolkits/basemap/__init__.py", line 2067, in drawparallels
if t is not None: linecolls[int(lat)][1].append(t)
  KeyError: 35

Then you need to install a newer version of Basemap.

First, uninstall the present version. For example if you are using Ubuntu 12.04, uninstall by typing

sudo apt-get remove python-mpltoolkits.basemap

Once you get rid of the older version, here is one way to install a new version:

  1. Install git

Eg. if you are running ubuntu, type:

sudo apt-get install git
  1. Pick a location for your git clone. From there:
git clone https://github.com/matplotlib/basemap.git
cd basemap
cd geos-3.3.3
./configure
make
sudo make install
cd ..
python setup.py build
sudo python setup.py install

Then, later, if you have run into a bug that has been fixed, you can update by going into that basemap directory and:

git pull
python setup.py build
sudo python setup.py install