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"midpoint_distance_m": 356.0, "start_elevation_m": 36.593496629093956, "end_elevation_m": 37.9860253951322, "start_xy": [ 276485.2227275014, 369160.4804257716 ], "end_xy": [ 276438.51139750116, 369247.7032475678 ] } }, "diagnostic_window_maxima": { "max_2m": { "gradient_pct": 48.90135415638497, "start_distance_m": 1105.0, "end_distance_m": 1107.0, "midpoint_distance_m": 1106.0, "start_elevation_m": 106.06321734490122, "end_elevation_m": 107.04124442802892, "start_xy": [ 275854.08876066323, 369562.2339696932 ], "end_xy": [ 275852.165572051, 369562.7829192006 ] }, "max_3m": { "gradient_pct": 45.14908893288663, "start_distance_m": 1105.0, "end_distance_m": 1108.0, "midpoint_distance_m": 1106.5, "start_elevation_m": 106.06321734490122, "end_elevation_m": 107.41769001288782, "start_xy": [ 275854.08876066323, 369562.2339696932 ], "end_xy": [ 275851.20397774485, 369563.05739395437 ] } }, "diagnostic_note": "Windows <=3 m are 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": 0.405, "obstruction_max_height_m": 26.85, "flagged_windows_m": [ 2, 3, 5, 10, 20, 50, 100 ] }, "structure_suppression": { "masked_fraction": 0.002, "windows_resited": [ 5.0, 10.0, 20.0, 50.0, 100.0 ], "windows_unresolved": [] }, "excluded_ranges_m": [ [ 995.0, 1000.0 ] ], "review": [ "short_window_divergence" ], "extent": [] }, "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_12_274368_20210302dtm.tif", "data/cache/wales/dtm_1m/wg_del_12_274369_20210307dtm.tif", "data/cache/wales/dtm_1m/wg_del_12_274370_20210307dtm.tif", "data/cache/wales/dtm_1m/wg_del_12_275368_20210302dtm.tif", "data/cache/wales/dtm_1m/wg_del_12_275369_20210307dtm.tif", "data/cache/wales/dtm_1m/wg_del_12_275370_20210307dtm.tif", "data/cache/wales/dtm_1m/wg_del_12_276368_20210302dtm.tif", "data/cache/wales/dtm_1m/wg_del_12_276369_20210307dtm.tif", "data/cache/wales/dtm_1m/wg_del_12_276370_20210307dtm.tif" ], "calculated_at": "2026-08-12T09:10:12+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_12_274368_20210302dtm.tif", "wg_del_12_274369_20210307dtm.tif", "wg_del_12_274370_20210307dtm.tif", "wg_del_12_275368_20210302dtm.tif", "wg_del_12_275369_20210307dtm.tif", "wg_del_12_275370_20210307dtm.tif", "wg_del_12_276368_20210302dtm.tif", "wg_del_12_276369_20210307dtm.tif", "wg_del_12_276370_20210307dtm.tif" ], "elevation_capture_dates": [ "07-03-2021" ], "climb_origin": "discovered", "notes": "Coarse pass: max 15.1% over 200 m (Terrain 50), gain 167.8 m over 1509 m way. EXTENDED by graph walk: +4 segment(s) at base, +1 at top (stop: base=no_descending_continuation, top=no_ascending_continuation; min_avg=2.0%). Review before adopting. DEDUPE: absorbed 4 overlapping proposal(s): discovered-lane-53-2056-3-8511, discovered-lane-53-2075-3-8589, discovered-lane-53-2078-3-8790, discovered-lane-53-2086-3-8625 ADOPTED (notable slice 2026-08-11): big-gain. AUTO-NAMED from gazetteer (hypothesis, unreviewed): was 'Discovered lane (53.2120, -3.8669)'.", "naming_note": "auto-named from gazetteer (hypothesis, unreviewed); discovered as 'Discovered lane (53.2120, -3.8669)'" }, "area": { "place": "Llanbedr-y-cennin", "county": "Conwy - Conwy" }, "reported_claims": [], "confidence": "U", "shape": { "ascent_concentration": 0.301, "concentration_window_frac": 0.25, "longest_pitch_10pct_m": 212.0, "shape_class": "sustained" } }