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at raster-noise scale (1-sigma raster noise alone is roughly +/-7 pp at 2 m and +/-5 pp at 3 m on a 1 m DTM). Diagnostic use only: never a headline or ranking value.", "quality_summary": { "overhead_obstruction": { "obstruction_threshold_m": 2.0, "obstructed_fraction": 0.703, "obstruction_max_height_m": 24.83, "flagged_windows_m": [ 2, 3, 5, 10, 20, 25, 50, 100 ] }, "structure_suppression": { "masked_fraction": 0.004, "windows_resited": [ 2.0, 3.0, 5.0, 10.0, 20.0, 25.0 ], "windows_unresolved": [] }, "no_bench_suppression": { "masked_fraction": 0.091, "windows_resited": [], "windows_unresolved": [] }, "excluded_ranges_m": [ [ 340.0, 370.0 ], [ 2480.0, 2670.0 ], [ 3260.0, 3410.0 ] ], "review": [], "extent": [ "descends_at_end" ] }, "provenance": { "analysis_version": "0.1.0", "sample_interval_m": 1.0, "interpolation": "bilinear", "smoothing": "none", "gradient_windows_m": [ 5.0, 10.0, 20.0, 25.0, 50.0, 100.0 ], "diagnostic_windows_m": [ 2.0, 3.0 ], "elevation_crs": "EPSG:27700", "elevation_resolution_m": 1.0, "elevation_tiles": [ "data/cache/wales/dtm_1m/wg_del_11_280356_20210302dtm.tif", "data/cache/wales/dtm_1m/wg_del_11_280357_20210302dtm.tif", "data/cache/wales/dtm_1m/wg_del_11_280358_20210302dtm.tif", "data/cache/wales/dtm_1m/wg_del_11_280359_20210302dtm.tif", "data/cache/wales/dtm_1m/wg_del_11_281356_20210302dtm.tif", "data/cache/wales/dtm_1m/wg_del_11_281357_20210302dtm.tif", "data/cache/wales/dtm_1m/wg_del_11_281358_20210302dtm.tif", "data/cache/wales/dtm_1m/wg_del_11_281359_20210302dtm.tif", "data/cache/wales/dtm_1m/wg_del_11_282356_20210302dtm.tif", "data/cache/wales/dtm_1m/wg_del_11_282357_20210302dtm.tif", "data/cache/wales/dtm_1m/wg_del_11_282358_20210302dtm.tif", "data/cache/wales/dtm_1m/wg_del_11_282359_20210302dtm.tif" ], "calculated_at": "2026-08-12T09:09:48+00:00", "road_source": "OpenStreetMap (local PBF extract)", "road_attribution": "\u00a9 OpenStreetMap contributors, ODbL", "osm_pbf_path": "data/cache/pbf/wales-2026-08-11.osm.pbf", "osm_snapshot": "2026-08-10T20:21:40Z", "elevation_provider": "Welsh Government", "elevation_dataset": "Welsh Government LiDAR 1m DTM (2020-2023)", "elevation_licence": "Open Government Licence v3 \u2014 \u00a9 Crown copyright Welsh Government", "elevation_catalogue_layer": "geonode:welsh_government_lidar_tile_catalogue_2020_2023", "elevation_tile_ids": [ "wg_del_11_280356_20210302dtm.tif", "wg_del_11_280357_20210302dtm.tif", "wg_del_11_280358_20210302dtm.tif", "wg_del_11_280359_20210302dtm.tif", "wg_del_11_281356_20210302dtm.tif", "wg_del_11_281357_20210302dtm.tif", "wg_del_11_281358_20210302dtm.tif", "wg_del_11_281359_20210302dtm.tif", "wg_del_11_282356_20210302dtm.tif", "wg_del_11_282357_20210302dtm.tif", "wg_del_11_282358_20210302dtm.tif", "wg_del_11_282359_20210302dtm.tif" ], "elevation_capture_dates": [ "02-03-2021" ], "climb_origin": "discovered", "notes": "Coarse pass: max 13.5% over 200 m (Terrain 50), gain 201.9 m over 3386 m way. EXTENDED by graph walk: +1 segment(s) at base, +0 at top (stop: base=no_descending_continuation, top=no_ascending_continuation; min_avg=2.0%). Review before adopting. ADOPTED (notable slice 2026-08-11): big-gain. AUTO-NAMED from gazetteer (hypothesis, unreviewed): was 'Discovered lane (53.1033, -3.7602)'.", "naming_note": "auto-named from gazetteer (hypothesis, unreviewed); discovered as 'Discovered lane (53.1033, -3.7602)'" }, "area": { "place": "Nant-y-Rhiw", "county": "Conwy - Conwy" }, "reported_claims": [], "confidence": "B", "shape": { "ascent_concentration": 0.307, "concentration_window_frac": 0.25, "longest_pitch_10pct_m": 143.0, "shape_class": "sustained" } }