Data archive: Geometric Optics with Aperture Diffraction (GOAD)

# Data archive: *Geometric Optics with Aperture Diffraction* (GOAD) Data and key figures underlying the manuscript: - **H. Ballington**, *Geometric Optics with Aperture Diffraction*, submitted to the *Journal of Quantitative Spectroscopy and Radiative Transfer* (2026).- GOAD source code: <https://github.com/hballington12/goad> This archive contains the single-scattering data behind each comparison figure in the manuscript, together with the plotting scripts needed to regenerate those figures from the data. ## Contents 1. `1_fixed_orientation/` — GOAD vs ADDA for a hexagonal column at fixed orientation, size parameter `X = 63.4` (pristine and absorbing cases).2. `2_orientation_averaged/` — GOAD vs ADDA for the same column, averaged over 96 orientations.3. `3_aggregate_pgoh/` — GOAD vs PGOH (physical-geometric optics hybrid) for an 8-column hexagonal aggregate, `X = 1000`.4. `4_saito_yang_2023_iitm/` — GOAD vs the invariant-imbedding T-matrix (IITM) of Saito & Yang (2023) for a unit-aspect hexagonal column, `X = 316`. Each subdirectory mirrors the layout its plotting script expects and carries its own `README.md`. See those for the specific data files, particle parameters, and provenance. ## Regenerating a figure Each subproject is a self-contained `uv` project. From inside a subproject directory: ```bashcd 1_fixed_orientationuv run plotting/mueller_matrix_plotter.py # writes PNGs into figs/``` (The dependencies — `numpy`, `pandas`, `matplotlib` — are declared in each `pyproject.toml`.) ## Data formats - **GOAD** `mueller_scatgrid` — columns: `theta phi` followed by the 16 Mueller matrix elements in row-major order (`S11 S12 S13 S14 S21 ...`). `mueller_scatgrid_1d` is the azimuthally integrated version (`theta` + 16 elements). `results.json` holds the integrated scattering parameters (cross-sections, asymmetry parameter, backscatter).- **ADDA** `mueller_scatgrid` — columns: `theta phi s11 s12 ... s44` (header row present). `CrossSec-X`/`CrossSec-Y` give the extinction/absorption cross-sections per incident polarisation.- **PGOM** `pgom_out.dat` — header lines with integrated cross-sections followed by `angle` + 16 Mueller elements per row (cross-sections are in `k`-normalised units; see `3_aggregate_pgoh/README.md`). ## Provenance and licensing - GOAD data were computed by the author with the open-source GOAD code (link above).- ADDA reference data were computed by the author with ADDA (Yurkin & Hoekstra). PGOM output was computed by the author using the physical-geometric optics hybrid method (Bi et al., 2011).- The **IITM reference data (Saito & Yang, 2023) are third-party and are NOT redistributed here.** Subproject 4 contains only a strong link back to the original source; see `4_saito_yang_2023_iitm/data/iitm/README.md`.- Suggested licence for the author-generated data in this archive: CC-BY-4.0. The linked third-party dataset remains under the terms of its original publication.