LiDAR Height

LiDAR ground height

—

m ODN

Start GPS to query the Environment Agency DTM.

Centre cell—

3×3 median—

3×3 range—

GPS position

No fix

Current reported accuracy

— m

Android/browser horizontal accuracy radius (95% confidence).

Target ≤ 1.0 m Waiting

Best nearby fix—

Latitude—

Longitude—

BNG easting—

BNG northing—

Fix age—

For the best fix, stand still with a clear view of the sky and enable Precise location for this site.

Compare two points

Records use the displayed 3×3 median

Point A

—

Not recorded

Point B

—

Not recorded

B − A—

Separation—

Manual test location

Useful for testing from a desktop. This does not use or change the phone GPS.

What the numbers mean

GPS accuracy is the phone/browser estimate for horizontal position, not height. The app ignores the phone's GPS altitude.

LiDAR height comes from the Environment Agency 1 m bare-earth DTM. The source surveys are specified at about ±0.15 m vertical RMSE, but your practical result also depends on horizontal GPS error and local slope.

Grid conversion uses the Ordnance Survey OSTN15 transformation grid, loaded through this site's Cloudflare proxy.