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Plot Self-Spectrum for a SeaSondeRCS Object

Source: R/SeaSondeRCS.R
seasonder_SeaSondeRCS_plotSelfSpectrum.Rd

This function generates a plot of the self-spectrum (in dB) for a specified antenna and range cell from a SeaSondeRCS object. The Doppler frequencies are converted to the desired units before plotting. Optionally, it overlays additional elements such as smoothed self-spectrum lines, first-order region (FOR) vertical lines, and noise level lines.

Usage

seasonder_SeaSondeRCS_plotSelfSpectrum(
  seasonder_cs_object,
  antenna,
  range_cell,
  doppler_units = "normalized doppler frequency",
  plot_FORs = FALSE
)

Arguments

seasonder_cs_object

A SeaSondeRCS object containing spectral and metadata.

antenna

An integer or vector specifying the antenna(s) to extract the self-spectrum from.

range_cell

An integer indicating the range cell to extract the spectrum.

doppler_units

A character string specifying the desired Doppler units for the plot. Commonly "normalized doppler frequency" or "doppler frequency" (Hz). Default is "normalized doppler frequency".

plot_FORs

Logical. If TRUE, the function overlays elements related to the first order region (FOR) such as vertical lines at the FOR boundaries and the smoothed self-spectrum. Default is FALSE.

Value

A ggplot object representing the self-spectrum plot.

Details

The function performs the following steps:

  1. Retrieves the self-spectrum data for the given antenna and range cell using seasonder_getSeaSondeRCS_SelfSpectra.

  2. Converts the Doppler bin frequencies to the specified units using seasonder_SwapDopplerUnits.

  3. Converts the self-spectrum to dB using seasonder_SelfSpectra2dB and combines it with the Doppler values.

  4. Retrieves the Bragg Doppler angular frequency for plotting a reference vertical line.

  5. If plot_FORs is TRUE, overlays:

    • An orange line for the smoothed self-spectrum.

    • Blue vertical lines for FOR boundaries.

    • Red lines indicating the noise level across the Doppler spectrum.

  6. Finally, returns the ggplot object.

Examples

# Prepare a SeaSondeRCS object for plotting self-spectrum
apm_file <- system.file("css_data/MeasPattern.txt", package = "SeaSondeR")
apm_obj <- seasonder_readSeaSondeRAPMFile(apm_file)
#> seasonder_createSeaSondeRAPM:  APM object created successfully.
cs_file <- system.file("css_data/CSS_TORA_24_04_04_0700.cs", package = "SeaSondeR")
cs_obj <- seasonder_createSeaSondeRCS(cs_file, seasonder_apm_object = apm_obj)
#> new_SeaSondeRCS:  SeaSondeRCS object created successfully.
# Plot self-spectrum for antenna 1, range cell 5
p <- seasonder_SeaSondeRCS_plotSelfSpectrum(cs_obj, antenna = 1, range_cell = 5)
print(p)