Eye4Software Hydromagic

Hydrographic Survey Software


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Importing NMEA0183 data files

This feature allows users to create a raw data file directly from a previously recorded NMEA0183 session- or log file.
This can be used to retrieve sounding data from, for instance a remote controlled survey vessel such as the OceanScience Z-Boat 1800.

This option can only be used when the depth and position data is recorded into the same file.

The new importing tool allows you to set the date and in which time zone the sounding was recorded.
This way, together with the time information in the NMEA0183 data, the sounding can be time tagged, so it can be corrected with a tide file if needed.

Z-Boat from OceanScience


NMEA0183 Import Tool

To start the NMEA0183 importing tool, select "Import NMEA0183..." from the "File" => "Import" menu as shown below.

NMEA0183 Importing Utility

In order to import data, you have to specify a local map projection first. In case you haven't done so, the application will prompt you to do this now.
After a map projection has been selected, the following dialog should appear:

NMEA0183 Importing Utility


Input folder

Instead of selecting a single file, you have to select a folder containing the file(s) to import.
The advantage of this approach is that it allows you to import multiple log files at once,
instead of having to select items them one by one.

Click the "Browse..." button to select a folder on a hard drive or SD card.
After changing this settings, the list of files will be refreshed automatically.

In the view at the bottom of the dialog, you can check the box in front of the files you want to import.


Depth settings

In order to correctly import the depth data, you have to set a couple of options as described below:

NMEA0183 sentence

Use this settings to select the NMEA0183 sentence used to extract depth from the log file.
Possible settings are: $SDDBK, $SDDBS, $SDDBT and $SDDPT.

Sentence Description
$SDDBK Depth below keel
$SDDBS Depth below surface
$SDDBT Depth below transducer
$SDDPT Depth and keel offset

Sounder offset

Use this box to set the transducer offset to be used. This is the distance between the bottom of the transducer to the waterline.
This settings is also called the static draft. If unknown, it is possible to leave this value zero and correct it later in the "Sounding Wizard".


Sounding date

To add correct date and time information to your sounding, you can use the "Date" and "Time zone" settings.
The time of the positions is stored in the NMEA0183 data as GMT time, so the correct time zone is required to convert the times to local time.
This settings are optional, however, if the sounding is going to be used with tide files, you will need the correct timestamps on your data !


Starting the conversion

When everything is set up, just click the "OK" button to start the import. You will see a progress indicator at the bottom of the screen.
When the sounding has been imported successfully, it will be displayed on the screen.

You can investigate the data by right clicking the generated RAW file(s) and select the "Analyze Data..." option.