{
  "schema": 1,
  "pack_id": "window-workshop",
  "retrieved_at": "2026-10-02",
  "evidence_class": "illustrative",
  "media_policy": "Original code-drawn geometry and SVGs only. No source photographs, agency diagrams, lidar, terrain or field measurements are reused.",
  "sources": [
    {"id":"WW-NPS-FINS","title":"Wall and Narrows","publisher":"National Park Service, Bryce Canyon National Park","url":"https://www.nps.gov/brca/learn/nature/wallandnarrows.htm","published_or_updated":"2021-09-04","retrieved_at":"2026-10-02","supports":"Thin remaining walls between eroded openings are termed fins.","rights":"Facts paraphrased; no media or expressive text copied."},
    {"id":"WW-NPS-ARCHES","title":"Arches","publisher":"National Park Service, Bryce Canyon National Park","url":"https://www.nps.gov/brca/learn/nature/arches.htm","published_or_updated":"2015-02-24","retrieved_at":"2026-10-02","supports":"Windows can develop in fins; arch/window terminology overlaps; bridge/arch process distinctions are qualified.","limits":"The eight library names are editorial shape labels, not an NPS taxonomy. No numeric naming threshold, erosion rate or predicted collapse time is adopted.","rights":"Facts paraphrased; no photographs or diagrams reused."},
    {"id":"WW-NPS-NATURAL-BRIDGE","title":"Natural Bridge","publisher":"National Park Service, Bryce Canyon National Park","url":"https://www.nps.gov/places/000/natural-bridge.htm","published_or_updated":null,"retrieved_at":"2026-10-02","supports":"NPS describes the named Bryce feature as an arch or window despite the name Natural Bridge.","limits":"Context link only. No dimensions, shape, location or hidden surfaces copied into the models.","rights":"Fact paraphrased and linked. NPS Photo / Peter Densmore is not reused."},
    {"id":"WW-NPS-MOSSY","title":"Mossy Cave Trailhead Wayside","publisher":"National Park Service, Bryce Canyon National Park","url":"https://www.nps.gov/places/mossy-cave-trailhead-wayside.htm","published_or_updated":"2024-10-10","retrieved_at":"2026-10-02","supports":"NPS describes Mossy Cave as a spring-formed alcove.","limits":"Context link only. The generic alcoves do not reconstruct Mossy Cave.","rights":"Fact paraphrased and linked; no wayside artwork or photography copied."},
    {"id":"WW-USGS-OCCLUSION","title":"Methodological considerations of terrestrial laser scanning for vegetation monitoring in the sagebrush steppe","publisher":"US Geological Survey publication catalogue; Environmental Monitoring and Assessment","authors":"Kyle E. Anderson and colleagues","url":"https://www.usgs.gov/publications/methodological-considerations-terrestrial-laser-scanning-vegetation-monitoring","doi":"10.1007/s10661-017-6300-0","published_or_updated":"2017-11-01","retrieved_at":"2026-10-02","supports":"Blocked line of sight creates unsampled regions; observations from additional positions can reduce occlusion.","limits":"Study concerns vegetation. Only the general line-of-sight principle is applied by inference to our original rock diagram. No scan count, accuracy or coverage percentage is transferred.","rights":"General principle paraphrased from catalogue abstract. Article figures/data not copied; USGS hosting is not treated as a blanket article license."},
    {"id":"WW-USGS-DEM","title":"Lidar Base Specification: Glossary","publisher":"US Geological Survey","url":"https://www.usgs.gov/ngp-standards-and-specifications/lidar-base-specification-glossary","published_or_updated":null,"retrieved_at":"2026-10-02","supports":"DEM definition: elevations at regularly spaced horizontal locations, normally representing bare-earth terrain.","limits":"The inability of one height per horizontal sample to represent both roof and underside is a mathematical explanation, not a claim that all airborne point clouds lack every undercut return.","rights":"Definition paraphrased; no source media copied."}
  ],
  "claims": [
    {"id":"WW-C1","text":"Fins are thin rock walls and can contain windows.","source_ids":["WW-NPS-FINS","WW-NPS-ARCHES"],"classification":"source-backed terminology"},
    {"id":"WW-C2","text":"A through-window and a blind alcove have different connected open-space geometry.","source_ids":[],"classification":"explicit definition within original mathematical model"},
    {"id":"WW-C3","text":"A blocked observation direction leaves unobserved surfaces; a second direction may reveal more.","source_ids":["WW-USGS-OCCLUSION"],"classification":"geometric inference from general observation principle"},
    {"id":"WW-C4","text":"A single-valued height field cannot encode two elevations at the same horizontal coordinate.","source_ids":["WW-USGS-DEM"],"classification":"mathematical limitation, informed by DEM definition"},
    {"id":"WW-C5","text":"Named Bryce examples are context only; every rendered solid is generic and dimensionless.","source_ids":["WW-NPS-NATURAL-BRIDGE","WW-NPS-MOSSY"],"classification":"scope disclosure"}
  ],
  "model_limits": ["No actual park hidden surface is asserted", "No physical scale, coordinates or field resolution", "No erosion simulation or chronology", "No stress analysis, stability estimate or collapse prediction", "No ground-scan substitution", "Independent geologist review remains pending"]
}