Three new visualizations complementing existing SVF/openness/LRM/MSRM:
- RRIM (Red Relief Image Map): RGB composite combining positive openness
(R), inverted slope (G), negative openness (B). Uses ray-tracing
to compute both openness values in a single pass.
- Multi-Hillshade RGB: 3 azimuths (315°, 135°, 45°) mapped to R/G/B
channels with slope blending. Color reveals structure orientation.
- Local Dominance: (dem - local_min) / (local_max - local_min) using
min/max filters. Measures local height position — complements openness.
Also adds:
- _compute_openness_both() helper for shared ray-tracing (used by RRIM)
- xp_maximum_filter() in gpu.py (GPU/CPU abstraction)
- Entries in COLORMAPS, RGB_LEGENDS, VIZ_STEPS, and is_rgb detection
- All NaN handling follows existing patterns (nan_mask restoration)
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
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