JV_svpedit (Module within jview)

Description

JV_svpedit.c implements the functionality for interactive editing and visualization of Sound Velocity Profiles (SVPs) within the jview application. It provides a dedicated X-windows-based interface that allows users to inspect, navigate, and modify SVP data, which is a critical component for accurate bathymetric data processing and correction.

Key Features and Functions

  • GUI Management (manage_SVP_events, refresh_SVP_window):
    • manage_SVP_events: Serves as the central event handler for the SVP editing widget. It processes all relevant X-events (Expose, EnterNotify, LeaveNotify, KeyPress, ButtonPress, MotionNotify, ButtonRelease) that occur within the SVP display windows and their associated control buttons.
    • refresh_SVP_window: Ensures that the visual state of a specified SVP display window or button is kept up-to-date by triggering a redraw.
  • SVP Navigation and Display Controls:
    • Keyboard Shortcuts (within manage_SVP_events’s KeyPress handler): KEY_UP, KEY_DOWN (adjust vertical viewing range), KEY_LEFT, KEY_RIGHT (adjust horizontal viewing ranges for speed, temperature, and salinity axes).
    • Button Controls (within manage_SVP_events’s ButtonPress handler): button_window[15] (Previous SVP), button_window[16] (Next SVP), button_window[17] (Reset View), button_window[18] (Write SVPs).
  • Interactive SVP Editing and Flagging (within manage_SVP_events’s ButtonRelease handler):
    • Rubber-banding Selection: j_rubber_band is used to define a rectangular selection region.
    • Flagging Data Points (Left-click - button1 release): Calls flag_svp(FLAG_SVP, ...) to mark individual SVP data points as flagged if they fall within the selected region.
    • Unflagging Data Points (Right-click - button3 release): Calls flag_svp(UNFLAG_SVP, ...) to clear the flagged status of data points within the selected region.
    • Zooming Plot (Middle-click - button2 release): Adjusts the current plot’s view to magnify the selected region.
  • SVP Data Management (init_SVP, load_up_svp_nav, search_for_closest_svp, flag_svp, reset_svp_view, write_out_svps):
    • init_SVP: Initializes various global flags and variables pertinent to SVP handling.
    • load_up_svp_nav: Processes geographical coordinates of each loaded water column.
    • search_for_closest_svp: Identifies the loaded SVP that is geographically closest to a given pixel coordinate.
    • flag_svp: Modifies the flag status of individual data points within the currently selected SVP.
    • reset_svp_view: Resets all viewing range variables to their default values.
    • write_out_svps: Iterates through all loaded SVPs and writes any modified ones back to disk.
  • SVP Visualization (plot_svp, draw_svp):
    • plot_svp: The main rendering function for SVP data, clearing windows, configuring coordinate systems, drawing grids/labels, and plotting data points (highlighting flagged points).
    • draw_svp: A helper function that draws simplified markers for SVP locations on a larger map.

How It Works

The JV_svpedit module operates as an interactive editor within jview, allowing users to load, display, and modify Sound Velocity Profile data. It manages GUI elements like buttons and sliders to control navigation through SVPs, adjust display ranges, and apply edits. User interactions (mouse clicks, keyboard input) are captured by event handlers, which then trigger functions to update the SVP data, recalculate visualizations, and save changes. This module is tightly integrated with jview’s core event loop and global state, ensuring that SVP edits are reflected across the application and can be persistently stored.

Dependencies

  • JV_global.h: Contains global variables and common definitions used across the entire jview application suite.
  • JV_svpedit.h: This module’s own header file, which declares the function prototypes and data structures specific to SVP editing functionalities.
  • GUI and Graphics Functions: Includes jX_is_win, jhc_scaled_values, j_rubber_band, hilite_window, write_icon, jhc_shape, jhc_line, jhc_text for managing GUI elements, drawing primitives, and text rendering.
  • Projection and Time Utilities: Project (for geographic projection) and stdtime_nicetime (for time formatting).
  • Water Column (SVP) I/O: jWC_write (for writing SVP data).

Notes

JV_svpedit.c is indispensable for quality control and refinement of Sound Velocity Profile data within the jview application. It empowers users to visually analyze SVP casts, identify and flag anomalous data points, adjust viewing parameters, and save corrected profiles, thereby ensuring the highest possible accuracy for subsequent bathymetric data processing steps.