Quick Start Guide to the CTI Sound Velocity Editor

The CTI Sound Velocity Editor is a utility program distributed with SonarWiz used to import and edit Sound Velocity Profiles (SVP). Since SVPs can be stored in a wide variety of formats, the CTI Sound Velocity Editor uses a template system that makes it easier to import and edit SVP data in the formats you use frequently.

Example File

The example SVP file used in this guide consists of a 15 line header followed by the cast data. Each row consists of a sound velocity observation. The instrument was lowered from the surface down to the seabed and retracted to the boat. In all, there are over 600 observations in the file (one per row).

Open

Any text format that consists of header rows (to be ignored) and 1 row of data per velocity observation can be imported.

Instructions

1. To Import a SVP file into a SonarWiz project, Right-Click the Sound Velocity Files branch of the Project Explorer and Select Edit/Import Sound Velocity Files… This will open the CTI Sound Velocity Editor.
   
   

   Open

   

    

2. In the CTI Sound Velocity Editor, Click the Import icon in the toolbar and select the text file you wish to import.
   
   

    

3. In the Import dialog, Click the New button in the Templates section and fill out the name of the new template. I called it USGS Format in this example. In the future, if you need to import more SVP data using the same format, simply select the template you create here.
   
   

    

4. Set the number of header rows to skip over the file header, blank lines and column titles (if any). In this example, we have 15 header rows. Note that the Preview panel will darken the header rows we are skipping to give you a visual indication of the settings you make.
   We set the default delimiter to COMMA
   
   

    

5. The next step is to To define the value columns (fields) in the file. In our example file there are more fields than we need:
   Date Time, Pressure, Sound Velocity, Temperature, Battery
   each value is separated by a comma. We only need Pressure and Sound Velocity to define an SVP cast.
   
   

6. We start by skipping over the Date Time filed. Click the green '+' icon in the Fields section and specify Ignored for field type and COMMA for the delimiter.
   
   

    

7. You should now see the first field added to the Fields list, and the Preview panel will highlight the column in cyan and the delimiter in red. If you made a mistake, click the 'X' button and add the field again with the correct settings.
   
   

    

8. In our example file, the next field is pressure (dbar), which is roughly depth in meters. So we click the Green '+' again to define the second field as type: Depth and Delimiter: COMMA.
   
   
   

   
   This second field is now highlighted in the Preview panel:
   
   
   

    

9. The next column is Sound Velocity, so we add that to the template:
   
   

   
   and the Preview Panel shows that we have captured this field properly:
   
   

    

10. The remaining two columns: Temperature and Battery Voltage can be ignored. We add two more “Ignored columns” to the Fields definition as shown here:
    
    

     

11. In the Additional Options section, we have two important selections to make:

    1. Accept only the first down cast. If this option is checked, only the portion of the cast while the instrument was descending is accepted (so called “clean” water), the portion while the instrument was being retrieved is clipped from the data set.

    2. Bin SV profile into depth slices. Some sound velocity profilers can sample the sound velocity multiple times per second. This results in hundreds of redundant measurements in a deep-water cast. Using the bin option here will divide the water column into equally spaced vertical bins and average the sound velocity observations in each bin.
       
       

       Unfiltered down cast (left) 5-m binned downcast (right)

12. Click the Import SVP File button to import the data into the program.
    
    

     

     

13. Give the SVP file a Name and Description. Add the Latitude and Longitude and Timestamp of the cast observation. These values are used by SonarWiz to help assign the cast to the appropriate bathymetry files, so it is important to fill them out.
    
    

    
    NOTE: the Lat/Lon format is controlled in the Tools | Settings menu.

14. Click the Save icon in the toolbar to save the file to disk.
    
    

    
    SonarWiz will add the file to the Project Explorer:
    
    

    
    And the SVP location will be displayed in the map view:
    
    
    

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