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"gradient_pct": 34.56155069522803, "start_distance_m": 755.0, "end_distance_m": 758.0, "midpoint_distance_m": 756.5, "start_elevation_m": 129.2184984514133, "end_elevation_m": 130.25534497227014, "start_xy": [ 234987.1646766781, 238030.4673820528 ], "end_xy": [ 234986.8520773662, 238027.48371289048 ] } }, "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": 0.107, "obstruction_max_height_m": 21.62, "flagged_windows_m": [ 2, 3, 5, 10, 20, 25, 50, 100 ] }, "review": [], "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_14_233234_20210321dtm.tif", "data/cache/wales/dtm_1m/wg_del_14_233235_20210321dtm.tif", "data/cache/wales/dtm_1m/wg_del_14_233236_20210321dtm.tif", "data/cache/wales/dtm_1m/wg_del_14_233237_20210321dtm.tif", "data/cache/wales/dtm_1m/wg_del_14_233238_20210321dtm.tif", "data/cache/wales/dtm_1m/wg_del_14_234234_20210321dtm.tif", "data/cache/wales/dtm_1m/wg_del_14_234235_20210321dtm.tif", "data/cache/wales/dtm_1m/wg_del_14_234236_20210321dtm.tif", "data/cache/wales/dtm_1m/wg_del_14_234237_20210321dtm.tif", "data/cache/wales/dtm_1m/wg_del_14_234238_20210321dtm.tif", "data/cache/wales/dtm_1m/wg_del_24_235234_20210321dtm.tif", "data/cache/wales/dtm_1m/wg_del_24_235235_20210321dtm.tif", "data/cache/wales/dtm_1m/wg_del_24_235236_20210321dtm.tif", "data/cache/wales/dtm_1m/wg_del_24_235237_20210321dtm.tif", "data/cache/wales/dtm_1m/wg_del_24_235238_20210321dtm.tif" ], "calculated_at": "2026-08-12T09:07:36+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_14_233234_20210321dtm.tif", "wg_del_14_233235_20210321dtm.tif", "wg_del_14_233236_20210321dtm.tif", "wg_del_14_233237_20210321dtm.tif", "wg_del_14_233238_20210321dtm.tif", "wg_del_14_234234_20210321dtm.tif", "wg_del_14_234235_20210321dtm.tif", "wg_del_14_234236_20210321dtm.tif", "wg_del_14_234237_20210321dtm.tif", "wg_del_14_234238_20210321dtm.tif", "wg_del_24_235234_20210321dtm.tif", "wg_del_24_235235_20210321dtm.tif", "wg_del_24_235236_20210321dtm.tif", "wg_del_24_235237_20210321dtm.tif", "wg_del_24_235238_20210321dtm.tif" ], "elevation_capture_dates": [ "21-03-2021" ], "climb_origin": "discovered", "notes": "Coarse pass: max 14.2% over 200 m (Terrain 50), gain 219.8 m over 4573 m way. EXTENDED by graph walk: +2 segment(s) at base, +3 at top (stop: base=no_descending_continuation, top=no_ascending_continuation; min_avg=2.0%). Review before adopting. DEDUPE: absorbed 1 overlapping proposal(s): discovered-lane-52-0031-4-4126 ROAD-REVIEW: way 788051687: unnamed service way; way 788051687: service way, surface untagged ADOPTED (notable slice 2026-08-11): big-gain. AUTO-NAMED from gazetteer (hypothesis, unreviewed): was 'Discovered lane (52.0038, -4.4180)'.", "naming_note": "auto-named from gazetteer (hypothesis, unreviewed); discovered as 'Discovered lane (52.0038, -4.4180)'" }, "area": { "place": "Cwmpengraig", "county": "Sir Gaerfyrddin - Carmarthenshire" }, "reported_claims": [], "confidence": "B", "shape": { "ascent_concentration": 0.398, "concentration_window_frac": 0.25, "longest_pitch_10pct_m": 221.0, "shape_class": "sustained" } }