seasonder_exportRadialMetrics: Export Radial Metrics from a SeaSondeRCS Object

In SeaSondeR: Radial Metrics from SeaSonde HF-Radar Data

Export Radial Metrics from a SeaSondeRCS Object

Description

This function extracts and formats radial metrics from a SeaSondeRCS object for export. It processes the MUSIC table, computes various spectral metrics, applies antenna pattern corrections, and combines the results into a final data frame formatted according to predefined column specifications.

Usage

seasonder_exportRadialMetrics(seasonder_cs_object, AngSeg = list())

Arguments

seasonder_cs_object	A SeaSondeRCS object containing MUSIC detection data and related metadata.
AngSeg	An optional list of angular segments to be applied to the vector flag field (VFLG). Each element should be a numeric vector of length 3 defining a segment. Default is an empty list.

Details

The function proceeds as follows:

1. Retrieves the MUSIC table using seasonder_getSeaSondeRCS_MUSIC and the associated APM object.

2. Defines a template row with 34 predefined columns, initializing most numeric values to NA, except for specific defaults such as MSA1, MDA1, and MDA2 (set to 1440L).

3. Copies basic numeric fields and computes additional fields from the MUSIC table, such as the radial velocity (scaled by 100), range, range cell, doppler cell (shifted by -1), eigenvalue ratio, signal power ratio, and offset power ratio.

4. Computes the metric MDRJ by applying the function seasonder_computeMDRJ on the MUSIC row.

5. Extracts eigen decomposition results from each MUSIC row to populate the eigenvalue fields (MEI1, MEI2, MEI3).

6. Processes the DOA solutions stored in each MUSIC row: - For solutions retained as "single", geographic bearing corrections are applied to populate MSA1. - For dual-bearing solutions, the first two elements of the DOA bearings populate MDA1 and MDA2, respectively.

7. Computes additional spectral metrics such as the self-spectra conversion to dB (fields MA1S, MA2S, and MA3S) after subtracting the noise level (obtained for each antenna).

8. Based on the retained solution type (either "single" or "dual"), assigns location data (if available), sets selection flags, and computes additional output metrics (e.g., PPFG and PWFG).

9. Finally, all rows are combined into a data frame. If angular segments are provided, additional modifications to the vector flag (VFLG) are applied.

Value

A data frame with 34 columns containing the computed radial metrics. The columns include geographic coordinates, velocity components, range, bearing information, signal power metrics, noise thresholds, and computed spectral parameters.

Examples

# Prepare a SeaSondeRCS object with MUSIC data
apm_file <- system.file("css_data/MeasPattern.txt", package = "SeaSondeR")
apm_obj <- seasonder_readSeaSondeRAPMFile(apm_file)
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)
FOR <- seasonder_getSeaSondeRCS_FOR(cs_obj)
cs_obj <- seasonder_setSeaSondeRCS_FOR(cs_obj,FOR[4:5])
# Run MUSIC algorithm to populate MUSIC data
cs_obj <- seasonder_runMUSICInFOR(cs_obj)
radial_metrics <- seasonder_exportRadialMetrics(cs_obj, AngSeg = list(c(5, 30, 60)))
head(radial_metrics)

SeaSondeR documentation built on June 8, 2025, 10:50 a.m.