Quick Start Guide to exporting SEGY files

Owned by Patrick Zynda (Unlicensed)
2023-03-06
3 min read

This guide will show you how to export sub-bottom data in SEGY format from a SonarWiz project

This Quick Start Guide will take you step-by-step through exporting sub-bottom data from your SonarWiz project in SEGY format. For more information about the individual commands, please refer to the User Guide found in the Help Menu of SonarWiz.

By following this procedure, you will learn how to:

  • Export SEGY files from processed sub-bottom data in a SonarWiz project

  • Incorporate custom EBDIC headers into your exports

  • Choose the correct Trace Header byte locations for available data

Instructions

  1. Once you have processed the sub-bottom data in your Project, open the CSF to SEGY conversion utility which is located in the Tools tab under the CSF drop down menu.

     

  2. Choose the directory where to store the output SEGY files, the default is the SBP folder of the SonarWiz project.

     

  3. If desired, enable the Custom EBCDIC Header option and load in a template for the tool to parse into. There are multiple options available where a macro will fill in the appropriate information for individual files. For example if $FILENAME$ is inserted into the custom .txt file, the output EBCDIC header of the SEGY would have the .CSF files name inserted. For a full list of macro options added to an example EBCDIC header, see here.

     

  4. Configure the SEGY Export options that are available.

    The SEGY Sample Format can be adjusted between 16 and 32-bit options.
    The Coordinate Format allows you to choose from the positions stored to be in latitude and longitude or projected grid coordinates (from whichever coordinate system is being utilized in the project).

SEGY files do not contain a location to write the projection information used if you choose to stored grid coordinates (easting and northing)!

If you choose this option SonarWiz will set the coordinate units (bytes 89-90) = 1 and it is recommended to use a custom EBCDIC header which states the coordinate system used.

The Seismic Domain can be adjusted between setting the trace type to either use Depth or Time. Trace header bytes 29-30 will indicate the trace identification code (1 for time domain seismic data or 25 for depth domain seismic data) and this will not affect the options set in the Data Fields Table.

5. Choose the desired options in the Data Fields Table. The options available will vary depending on whether you have Topographic Corrections turned on or off. For more information, see here.

The goal is to choose options based on the downstream program that will read in the exported SEGY files. If you are storing the SEGY data for redundancy you can use the Standard SEGY V1 option in the profile drop down menu. Some programs (like Kingdom Suite) require all of the available fields to be stored in time and not depth so we have added a preloaded profile for this as well.

Any field set using a byte location that is stored in time will be scaled used the SEGY Time Field Scalar and can be used to add further precision to exports into fields that only stored up to milliseconds.


Our support team has worked through numerous datasets to match what various programs in the industry need to see in order to properly reimport the SEGY data, if you have any questions please do not hesitate to reach out.

6. Choose the files you need to export and select OK.

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