5. Glossary


Acquisition refers to recording and timestamping ADCP and Navigation feeds. For modern ADCP data it is done with either UHDAS or VmDAS. (Prior to the development of UHDAS, DAS 2.48 was used for the original narrowband 150kHz instrument.) Time stamping always comes from the acquisition computer. For UHDAS, that time is always in UTC and is synced to an NTP server (if available on the ship). For VmDAS data, times are usually UTC, and there is no control over the time zone.


NMEA serial feeds/line/data coming from RDI ADCPs

CODAS Averages

ADCP data and Navigation data that went through Preliminary Processing.

CODAS Processing

CODAS Processing refers to turning acquired data into scientific products. It is composed of two distinct stages: preliminary and post processing. Preliminary processing occurs once, to stage the data. Post-processing may involve some repetition (eg. editing or calibration).

Config Directory

The config directory contains cruise-specific files defining parameters required throughout the UHDAS Data processing. For VmDAS data, the config directlry also contains information needed to convert the VmDAS data into UHDAS-style data. By convention, the cruise-specfic configuration file used for processing has the suffix *_proc.py.

Control File

The control file resides in the processing directory, and is a sonar-specific file defining parameters required for use in the single-ping processing or for reformatting pre-averaged data into CODAS averages. By convention, its file name is qpy.cnt.

Data Products

Data products are generated by removing ship speed from measured velocities, possibly averaging further, and outputting data products in other forms. Data formats supported include html, netCDF, matlab files, and figures.

Navigation Data

NMEA serial feeds/line/data with position (GPS) or heading

Preliminary Processing

Depending on the input data, the preliminary processing: - converts VmDAS single-ping Data into UHDAS-style Data - applies Single-ping Processing to UHDAS and UHDAS-style Data - formats VmDAS Data and UHDAS Single-Ping Data into CODAS Averages Note that the different steps of the preliminary processing stated above are automatically managed by adcp_database_maker.py. or manually managed via a combination of comand-lines actions .

Project Directory

The Project directory is defined as the user’s main location for processing a given cruise. It is useful to use the cruise name in the name. This directory can be created within the work flow of adcp_database_maker.py

Processing Directory

Also referred as “Sonar Processing Directory” or “ADCP Processing Diretory”, this folder contains the CODAS averages of a given sonar. This directory is usually created via adcp_database_maker.py and, ultimately, adcptree.py.


the post-processing is composed of:

Single-Ping processing

The single-ping processing is a key component of the preliminary processing of VmDas or UHDAS single-ping level data. Single-ping processing includes transformations (from beam to earth coordinates), editing out acoustic interference, editing out data below the bottom (including the side-lobe interference), additional single-ping editing, and averaging in time. Read this article for more details on the single-ping processing.


Sonar is the combination of an ADCP instrument type (2 letters), a sampling frequency and a ping-type. Ex.: os75nb, os38bb. Some ADCPs don’t have variable ping-type thus their related sonar name is simply their instrument type and frequency. Ex.: wh300, bb150


ADCP and Navigation Data Acquired at sea by UHDAS (see folder architecture). It is composed of UHDAS single-ping Data and Codas Averages

UHDAS-style Data

ADCP and navigation data, in the directory structure and naming convention of UHDASdata, produced by the conversion of VmDAS Single-ping Data using either adcp_database_maker.py or a combination of command-line actions .

UHDAS single-ping Data

Single-ping level ADCP and Navigation data acquired by UHDAS, i.e. not averaged. It is composed of the following folders: raw, rbin and gbin (add link to folder architecture diagram)

VmDAS Data

ADCP and Navigation Data Acquired at sea by VmDAS. It is composed of VmDAS Single-ping Data ( ENR, N1R, N2R (N3R). and VmDAS Averages ( LTA and STA). Refer to this link for more information.

VmDAS Single-ping Data

Single-ping level ADCP and Navigatation data acquired by VmDAS It is composed of the following file types: ENR, N1R, N2R (N3R).

VmDAS Averages

ADCP and Navigation data that were averaged over time by VmDAS. into short-term and long-ter averages. They are contained in the following file types: LTA and STA.


Automated reformatting of VmDAS LTA or STA data includes the creation of a post-processing guide with hints about the next steps. The post-processing guide is stored in the Projext directory and typically has a suffix *proc.txt.


Automated preliminary processing of any VmDAS data includes the discovery of information about the VmDAS dataset, such as ping types, averaging length, and transducer offset (EA command). This information is stored in the Projext directory with a suffix *info.txt. The same file can be created by running vmdas_info.py.