LIVING SURVEY — measurements are reviewed continuously as new data and local evidence arrive. Seen a sign, a gate, or a better name? Submit an update no account needed · photos welcome via GitHub

← all climbs

FP 16

1264.0 m · net rise 87.3 m · total ascent 99.5 m · overall 6.9% · evidence quality U (needs confirmation) · Chevithorne · Devon ·

Shape: sustained — 41% of the climbing sits in a quarter of the distance; longest continuous stretch at 10%+ is 53 m.

Found purely from mapping and LiDAR data, and not yet matched against books, race records or lists — it may be well known to locals under a name we've never heard. It was cross-checked against the OS road network, surface models and map tags, but a discovery can still be an artifact of the terrain model or the map. Treat it as a well-evidenced hypothesis until someone has ridden it. If you know this road, tell us what you found — photographs, corrections and local knowledge all welcome; the map links below let you scout it first.

needs review short window divergence — treat short-window maxima here as provisional.

≈ Overhead cover (tree canopy or structures) spans 9% of this route — detected by comparing the surface model (DSM, treetops and rooftops) against the terrain model (DTM, bare ground). Under cover the bare-ground model is built from fewer laser returns, so metre-scale readings can wobble; maxima whose window sits in a covered zone are marked ≈ below — less certain — the flag does not say whether the true value is higher or lower. Longer windows average over more clean ground and are steadier.

Gradient ladder what do windows mean?

WindowMaximumLocated at
2 m (diagnostic)47%779–781 m
3 m (diagnostic)42%779–782 m
5 m37%777–782 m
10 m28%775–785 m
20 m22.4%849–869 m
25 m20.9%847–872 m
50 m≈17.3%738–788 munder overhead cover
100 m15.8%775–875 m

Map

Check this route yourself: Google Maps route via their router · Street View at the base where coverage exists · geojson.io our exact measured line · OpenTopoMap

No aerial layer here: Britain has no open or government source of aerial photography at road scale — the pan-government APGB imagery is licensed to the public sector only, unlike the LiDAR this survey is measured from. Street View, where it exists, is the visual check.

This climb's data: OCL JSON — the full gradient ladder, quality flags and provenance in the OpenClimb Ladder format.

Measured, not vetted. This page records what the laser record shows about the road's shape — nothing more. Nobody has necessarily ridden or inspected this road for the survey, and a page here is not a recommendation and no guarantee that the road is open, surfaced, rideable or safe. Gates, private sections, missing rights of way and hazards do not show up in elevation data. Check access and conditions on the ground and make your own judgment.

Ridden it, or know better? Submit data for this climb no account needed ·

Route colour = gradient over a 25 m window: <10% 10–20% 20–25% ≥25%

  © OpenStreetMap contributors · topo tiles © OpenTopoMap (CC-BY-SA) · vector tiles OpenFreeMap

FP 16 LiDAR hillshade map with contours

Profile

The map, profile and gradient chart share one position — move your pointer over them and the marker follows. Colors are the gradient bands; the shaded span is the steepest 25 m. Any 25 m figure is good to about a point either way (why).

FP 16 elevation profile
FP 16 rolling gradient profile
 

Measurement card

ElevationEnvironment Agency — EA LIDAR Composite DTM 1m (2022)
Resolution / CRS1.0 m grid, EPSG:27700; sampled every 1.0 m, bilinear interpolation
TilesSS9515.tif
Road centrelineOpenStreetMap (local PBF extract), snapshot 2026-08-26T20:22:15Z
Quality statusevidence quality U; review flags: short window divergence
AnalysisOCL 0.1.0, analysis 0.1.0, run summit-260905-summit-england-england-2026-08-27, calculated 2026-09-05

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/england/bulk_dtm_1m/SS9515.tif"
  ],
  "calculated_at": "2026-09-05T07:07:05+00:00",
  "road_source": "OpenStreetMap (local PBF extract)",
  "road_attribution": "\u00a9 OpenStreetMap contributors, ODbL",
  "osm_pbf_path": "data/cache/pbf/england-2026-08-27-roads.osm.pbf",
  "osm_snapshot": "2026-08-26T20:22:15Z",
  "run_id": "summit-260905-summit-england-england-2026-08-27",
  "elevation_provider": "Environment Agency",
  "elevation_dataset": "EA LIDAR Composite DTM 1m (2022)",
  "elevation_licence": "Open Government Licence v3 \u2014 \u00a9 Environment Agency",
  "elevation_coverage_id": "13787b9a-26a4-4775-8523-806d13af58fc__Lidar_Composite_Elevation_DTM_1m",
  "elevation_tile_ids": [
    "SS9515.tif"
  ],
  "route_summit_trim_m": 215.6,
  "route_summit_trim_loss_m": 7.6,
  "climb_origin": "discovered",
  "license": "ODbL-1.0",
  "license_url": "https://howsteep.org/licensing"
}