7k2omg

Description

7k2omg is a utility designed to convert Reson 7k (.s7k) data files into the OMG-HDCS (Ocean Mapping Group - Hydrographic Data Conversion System) merged file format. This tool extracts bathymetry, sonar settings, snippet, and watercolumn data from .s7k files and maps them to the corresponding structures in the OMG-HDCS format.

It supports both old and new 7k bathymetry and snippet packet types, handles various Reson sonar models, and provides options for ignoring specific data types, forcing old packet usage, and dealing with dual-head sonar systems. The output merged file is a foundational format for further processing and visualization within the OMG toolkit.

Usage 

7k2omg -s7k <input_name> -omg <omg_file_prefix> [-sonar <type>] [OPTIONS]

Arguments

| Option | Description | |—|—| | -s7k <input_name> | Required. Path to the input Reson 7k .s7k file. | | -omg <omg_file_prefix> | Required. Prefix for the output OMG-HDCS files. The tool will generate: * <omg_file_prefix>.merged: The main OMG-HDCS merged file. * <omg_file_prefix>.merged.ss_data: Snippet side-scan data (if not ignored). * <omg_file_prefix>.sonar_settings: Binary file containing 7k Sonar Settings and Remote Control Settings. * <omg_file_prefix>.watercol: Watercolumn data (if not ignored). | | -sonar [7125|7111|7101|7150|7160|20 (for T20P)] | Specifies the Reson sonar model. | | -v | Enable verbose output. | | -debug | Enable debug output. | | -ignore_flags | Ignores quality flags, treating all beams as valid. | | -ignore_snippets | Skips processing and writing of snippet data. | | -ignore_watercolumn | Skips processing and writing of watercolumn data. | | -dual_head | Stores the system identifier in the profile mode field, useful for dual-head systems. | | -force_old_bathy | Forces the use of old bathymetry packets (7006) even if new ones (7027) are present. | | -force_old_snippets | Forces the use of old snippet packets (7008) even if new ones (7028) are present. |

How It Works

  1. Initialization: Parses command-line arguments, setting input/output filenames and various flags (e.g., ignore_snippets, force_old_bathy, dual_head). Initializes Reson 7k data structures and j_EM_watercolumn.
  2. 7k Indexing: Calls build_Reson_7K_Index() (an external function) to create an index of all packet types within the .s7k file.
  3. File Opening: Opens the input .s7k file for reading. Creates the output OMG-HDCS merged file (.merged), snippet data file (.merged.ss_data), sonar settings file (.sonar_settings), and watercolumn file (.watercol).
  4. OMG Summary Header Initialization:
    • Determines bathy_id (7006 or 7027) and snippets_id (7008 or 7028) based on available packets and force_old_* flags.
    • Reads the first bathy packet to determine base_time.
    • Initializes an OMG_HDCS_summary_header structure, setting fileVersion, toolType (from -sonar option), refTime, numDepths, etc.
    • Writes this summary header to the .merged file.
    • Allocates memory for OMG_HDCS_beam structures.
  5. Ping Traversal Loop: Iterates through each Bathy packet (ping) found in the .s7k index:
    • Reads the Bathy packet (7006 or 7027) and extracts ping_time.
    • Searches the index for corresponding 7000_Sonar_Settings, 7503_Remote_Control_Settings, 7004_Beam_Geometry, and snippet/watercolumn records based on ping_time.
    • Reads these associated records.
    • OMG Profile Header Population: Populates an OMG_HDCS_profile_header structure:
      • ping_number, multi_ping_sequence, num_beams are set from bathy data.
      • td_sound_speed is set from sonar settings or bathy.
      • Various offsets to raw 7k packet headers are stored in the profile header and written to .sonar_settings.
      • Snippet sample descriptors are stored in the profile header.
      • profile.mode is set to drf.system_enumerator if dual_head.
    • OMG Beam Structure Population: For each beam (j) within the current ping:
      • Extracts beam_index.
      • beams[beam_index].Tx_steer, beams[beam_index].twtt, beams[beam_index].range, beams[beam_index].Rc_steer, beams[beam_index].beam_depress_angle are set from bathy and beam geometry data.
      • beams[beam_index].status and beams[beam_index].Q_factor are derived from quality flags, respecting ignore_flags.
      • beams[beam_index].reflectivity is set from signal strength or calculated from snippets.
      • Preliminary beams[beam_index].observedDepth and beams[beam_index].acrossTrack are calculated.
      • If snippet data is available:
        • beams[beam_index].centre_no, beams[beam_index].no_samples, beams[beam_index].offset, beams[beam_index].snippet_first_sample, beams[beam_index].snippet_last_sample are set.
        • Snippet samples are written to .merged.ss_data.
    • Watercolumn Data (-watercolumn): If watercolumn data is present and not ignored:
      • Calls convert_7K_watercolumn() to convert 7k watercolumn data to OMG format.
      • Calls j_EM_write_watercolumn() to write the OMG watercolumn data to .watercol.
    • Write to Merged File: OMG_HDCS_write_profile() and OMG_HDCS_put_raw_beams() write the populated profile header and beam data to the .merged file.
    • Increments num_bathy_recs.
  6. Cleanup: Frees allocated memory and closes all open files.

Output Files

  • <omg_file_prefix>.merged: Standard OMG-HDCS merged file.
  • <omg_file_prefix>.merged.ss_data: Snippet side-scan data (binary, raw short intensities).
  • <omg_file_prefix>.sonar_settings: Binary file containing 7k Sonar Settings and Remote Control Settings.
  • <omg_file_prefix>.watercol: Watercolumn data (binary).