demo_fernando

Description

demo_fernando is a simple, interactive demonstration program designed to illustrate how to extract basic elements of an EM1000 multibeam sonar data record from an OMG-HDCS merged file. It allows a user to input a record number (ping number) and then retrieves and displays the corresponding bathymetry (xyz coordinates), sidescan traces, and vessel motion (roll, pitch, heading, heave) for that ping.

This tool primarily serves as a debugging aid or a basic example for developers to understand the structure of EM1000 data within the OMG-HDCS format.

Usage 

demo_fernando <input_omg_file(.merged)> [-v]

Arguments

Option Description
<input_omg_file(.merged)> Required. The path to the input OMG-HDCS merged file.
-v Enable verbose output (not explicitly used in the provided code but present in USAGE).

Interactive Mode

After launching, the program will continuously prompt the user to “input rec num”. The user enters a ping number, and the program displays the requested data.

How It Works

  1. File Opening: Opens the specified OMG-HDCS merged file (.merged) and its corresponding sidescan data file (.ss_data).
  2. Interactive Loop: Enters an infinite loop (upthere:; and goto upthere;) to allow continuous interactive input.
  3. Record Number Input: Prompts the user to enter a recno (record number or ping number).
  4. Data Extraction: Calls give_me_traces_and_bathy (an external function, likely from Echo_calib.h or a linked library) with the input files and the provided recno. This function populates:
    • sstraces: A 2D array to store sidescan traces (up to 60 beams, 500 samples each).
    • xyz: A 2D array to store bathymetry coordinates (x, y, z) for up to 60 beams.
    • roll, pitch, heading, heave: Variables to store vessel motion data.
  5. Output to Console:
    • Prints the extracted roll, pitch, heading, and heave values.
    • For each of the 60 beams, it prints the xyz coordinates.
    • For each beam’s sidescan trace, it iterates through up to 500 samples. If a sample is non-zero, it prints “1” (effectively showing a binary presence of data in the trace).
  6. Loop Continuation: After displaying the data for one ping, it jumps back to upthere:; to prompt for another record number.

Output Files

This tool primarily outputs data to the console for interactive inspection. No persistent output files are generated by default.

Dependencies

  • OMG_HDCS_jversion.h: For OMG-HDCS data structures.
  • Echo_calib.h: (Assumed) For give_me_traces_and_bathy function.
  • support.h: For general utility functions.

Notes

This demonstration tool provides a basic, low-level way to inspect merged data. It’s particularly useful for debugging specific pings or understanding the internal data organization within an OMG-HDCS merged file. The hardcoded “EM1000” reference in the description suggests it was originally developed for that specific sonar type.