=== versions === python 3.12.0 | scikit-image 0.26.0 | numpy 2.5.4 | rasterio 1.5.2 | networkx 3.7 | scipy 1.18.1 === end points === start Pen-y-Pass: 264835 E, 355620 N | end Yr Wyddfa summit: 260988 E, 354376 N | straight-line distance 4043 m === rasters on a 10 m British National Grid === grid 900 x 800 cells | DEM 58-1074 m, missing 0 | WorldCover classes [10, 30, 40, 50, 60, 80, 90, 100] === OpenStreetMap footpaths === 688 ways, 18936 nodes, 196.4 km of path in the box named paths: Craig Fach Track; Crib Goch; Crib Goch North Ridge; Cwm Cneifion approach; Cylchdaith yr Wyddfa; Llanberis Path; Lliwedd; Llwybr Bwlch Moch; Llwybr Defaid; Llwybr Llyn Llydaw; Llwybr y Carw; Llwybr y Llwynog; Miners' Track; Pont Nant Efan; Pyg Track; Rhyd Ddu Path; Roman Road; Senior's Gully; Senior's Ridge; Snowdon Ranger Path; South Ridge; Watkin Path; Y Grib Bigog; Y Gribin; Y Gribyn sac_scale: (no sac_scale) 139.7 km, mountain_hiking 25.9 km, hiking 16.5 km, demanding_mountain_hiking 10.2 km, alpine_hiking 4.2 km 58 connected pieces; the largest holds 61% of the nodes start snapped 128 m, end snapped 1 m to the path network shortest OSM route: 5564 m, 171 min, 2480 m graded as scrambling | via Llwybr Llyn Llydaw 205 m, Craig Fach Track 711 m, (unnamed) 1076 m, Crib Goch 1378 m, (unnamed) 1609 m, Llanberis Path 513 m fastest OSM route without scrambles: 5614 m, 132 min, 0 m graded as scrambling | via Llwybr Llyn Llydaw 205 m, Craig Fach Track 711 m, (unnamed) 280 m, Craig Fach Track 923 m, Llwybr Bwlch Moch 2578 m, Pyg Track 336 m, Llanberis Path 513 m === cost surface === slope 18.6 deg median, 50.2 deg 99th percentile, 69.1 deg max Tobler speed: 5.04 km/h on the flat, 1.41 km/h at 20 deg, 0.27 km/h at 40 deg 10 Tree cover 7.4% of cells multiplier 1.5 30 Grassland 90.0% of cells multiplier 1.0 40 Cropland 0.0% of cells multiplier 1.2 50 Built-up 0.3% of cells multiplier 1.0 60 Bare / sparse 0.5% of cells multiplier 1.25 80 Permanent water 1.8% of cells multiplier inf 90 Herbaceous wetland 0.0% of cells multiplier 2.0 100 Moss and lichen 0.0% of cells multiplier 1.1 combined cost: 0.71-8028.15 s/m, 12932 impassable water cells === accumulated cost and least-cost path === MCP_Geometric on 720,000 cells: 0.15 s | accumulated cost at the summit 186 min least-cost path: 5833 m, 516 cells | 12% within 50 m of the OSM route, 63% within 50 m of any mapped path, mean distance from the OSM route 503 m route length Tobler Naismith ascent water >30 deg steepest straight line 3920m 676mn 141mn 938m 369m 32% 62deg OSM walkers' route 5614m 124mn 149mn 815m 0m 19% 39deg OSM shortest route 5564m 161mn 158mn 910m 0m 15% 50deg least-cost path 5833m 154mn 160mn 903m 0m 5% 35deg === cost weights and the route === Distance only 4229 m | 428 min | ascent 959 m | water 0 m | 56% over 30 deg | 18% within 50 m of the OSM route, 31% of any path | 0.12 s Slope only (Tobler) 5571 m | 157 min | ascent 845 m | water 1874 m | 6% over 30 deg | 31% within 50 m of the OSM route, 62% of any path | 0.15 s Slope + land cover 5833 m | 154 min | ascent 903 m | water 0 m | 5% over 30 deg | 12% within 50 m of the OSM route, 63% of any path | 0.14 s Slope + land cover + 4x above 30 deg 5959 m | 151 min | ascent 908 m | water 0 m | 2% over 30 deg | 12% within 50 m of the OSM route, 43% of any path | 0.15 s As above + 0.5x on mapped paths 6003 m | 152 min | ascent 904 m | water 0 m | 2% over 30 deg | 12% within 50 m of the OSM route, 77% of any path | 0.15 s 4-connected moves: 6600 m | 8-connected moves: 5833 m (diagonals cut the zigzag by 11.6%) === anisotropic cost with scipy.sparse.csgraph === graph: 720,000 nodes, 5,641,358 directed edges, built in 0.25 s | Dijkstra 0.21 s accumulated cost at the summit 113 min (isotropic: 186 min) anisotropic least-cost path: 5153 m | Tobler 111 min | ascent 764 m | 32% over 30 deg | 55% within 50 m of the OSM route, 91% of any path | mean offset 102 m === figures === saved 5 figures to C:\Users\Sean.Blaney\source\tgis-b7-3\tutorial-code\least-cost-path-analysis-python\output