Know where
you’re standing.
Your location, matched to the project’s chainage markers.
33+000 → 63+200 · 100 m marker spacing
Open in Safari on your iPhone and allow location access. Keep this page open while tracking.
Your distance to the alignment
Use my location to see your distance to the nearest chainage.
Green: alignment · Blue: your position · Orange: distance line.
Check a coordinate manually
Use a known coordinate to check the result. Manual checks are clearly labelled.
How this estimate works
The nearest segment between consecutive named chainage markers is selected. Your position is projected onto it, and the chainage is interpolated between the two marker values. Curves between 100 m markers are approximated with straight segments. The source is RK9092 Piet Retief-Bloemendal.kml.
GPS accuracy describes the position fix, not the total chainage error. Check against known site chainage markers before relying on this for records. Use survey equipment for setting out. Points beyond the alignment ends are not extrapolated. A distance above 50 m is flagged as off the alignment.
Chainage calculations run on your device. This app does not store your GPS readings. OpenStreetMap tiles require an internet connection and reveal the viewed map area to the tile provider. Opening the Google Maps link shares the selected coordinate with Google.