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282802.57161240664 ], "end_xy": [ 296569.3221786155, 282851.8526972653 ] }, "min_100m": { "gradient_pct": -13.414733394927737, "start_distance_m": 2852.0, "end_distance_m": 2952.0, "midpoint_distance_m": 2902.0, "start_elevation_m": 309.48573610525466, "end_elevation_m": 296.0710027103269, "start_xy": [ 296586.2569049408, 282772.9697701739 ], "end_xy": [ 296566.86010682426, 282870.6925009398 ] } }, "diagnostic_window_maxima": { "max_2m": { "gradient_pct": 34.12321137628567, "start_distance_m": 183.0, "end_distance_m": 185.0, "midpoint_distance_m": 184.0, "start_elevation_m": 251.19059025927288, "end_elevation_m": 251.8730544867986, "start_xy": [ 297042.7607531468, 280343.79896927305 ], "end_xy": [ 297042.7126940141, 280345.7983917696 ] }, "max_3m": { "gradient_pct": 29.226795416482787, "start_distance_m": 183.0, "end_distance_m": 186.0, "midpoint_distance_m": 184.5, "start_elevation_m": 251.19059025927288, "end_elevation_m": 252.06739412176736, "start_xy": [ 297042.7607531468, 280343.79896927305 ], "end_xy": [ 297042.6886644477, 280346.79810301785 ] } }, "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": 0.159, "obstruction_max_height_m": 18.88, "flagged_windows_m": [] }, "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_28_296280_20220314dtm.tif", "data/cache/wales/dtm_1m/wg_del_28_296281_20220314dtm.tif", "data/cache/wales/dtm_1m/wg_del_28_296282_20220314dtm.tif", "data/cache/wales/dtm_1m/wg_del_28_296283_20220314dtm.tif", "data/cache/wales/dtm_1m/wg_del_28_297280_20220226dtm.tif", "data/cache/wales/dtm_1m/wg_del_28_297281_20220226dtm.tif", "data/cache/wales/dtm_1m/wg_del_28_297282_20220226dtm.tif", "data/cache/wales/dtm_1m/wg_del_28_297283_20220226dtm.tif" ], "calculated_at": "2026-08-12T09:08:23+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_28_296280_20220314dtm.tif", "wg_del_28_296281_20220314dtm.tif", "wg_del_28_296282_20220314dtm.tif", "wg_del_28_296283_20220314dtm.tif", "wg_del_28_297280_20220226dtm.tif", "wg_del_28_297281_20220226dtm.tif", "wg_del_28_297282_20220226dtm.tif", "wg_del_28_297283_20220226dtm.tif" ], "elevation_capture_dates": [ "14-03-2022", "26-02-2022" ], "climb_origin": "discovered", "notes": "Coarse pass: max 11.3% over 200 m (Terrain 50), gain 46.3 m over 3353 m way. EXTENDED by graph walk: +0 segment(s) at base, +1 at top (stop: base=no_descending_continuation, top=no_ascending_continuation; min_avg=2.0%). Review before adopting. ADOPTED (notable slice 2026-08-11): clean-steep. AUTO-NAMED from gazetteer (hypothesis, unreviewed): was 'Discovered lane (52.4249, -3.5164)'.", "naming_note": "auto-named from gazetteer (hypothesis, unreviewed); discovered as 'Discovered lane (52.4249, -3.5164)'" }, "area": { "place": "Cwm Jonathan", "county": "Powys - Powys" }, "reported_claims": [], "confidence": "A", "shape": { "ascent_concentration": 0.414, "concentration_window_frac": 0.25, "longest_pitch_10pct_m": 135.0, "shape_class": "sustained" } }