VER 1.0 // GREAT BRITAIN // SUMMIT VERIFICATION
[MARILYN TRACKER] Northing verifies Marilyn summit arrivals by auditing GPS activity data against prominence-classified hill coordinates across Great Britain. All 1,550 Marilyns are covered. Verification tolerance: 200 metres.
01. Marilyn Definition
[CLASSIFICATION] A Marilyn is a hill or mountain in Great Britain with a topographic prominence of 150 metres or more, regardless of absolute height. The classification was coined by Alan Dawson in his 1992 book The Relative Hills of Britain.
[PROMINENCE] Topographic prominence measures the height difference between a summit and the highest col connecting it to a higher peak. A prominence of 150 metres means the hill stands at least 150 metres above any surrounding terrain connection to higher ground.
[COUNT] There are 1,550 Marilyns across Great Britain: England, Scotland, and Wales. A hill can qualify as both a Munro and a Marilyn.
[COORDINATES] Northing uses Ordnance Survey summit grid references, converted to WGS84 coordinates for GPS matching.
02. Database Coverage
1,550
[MARILYNS]
All current Marilyns. England, Scotland, and Wales.
150m
[MIN PROMINENCE]
Minimum topographic prominence for Marilyn classification.
200m
[TOLERANCE]
Horizontal coordinate tolerance for summit verification.
03. How Marilyn Verification Works
[01 IMPORT]
Connect Strava or upload a GPX or FIT file. Northing reads the raw GPS coordinate track from your activity.
[02 AUDIT]
Each coordinate point is checked against all 1,550 Marilyn summit positions. An ascent is verified if any point falls within 200 metres of the summit coordinate.
[03 RECORD]
Verified ascents are written to your ledger with date, hill name, and activity source. The record is private. No social feed.
04. Accepted Activity Data
- [STRAVA] Strava sync. Connect your Strava account and Northing imports completed activities for audit against all 1,550 Marilyns. Post-hoc only — no real-time tracking.
- [GPX] GPX file upload. Export from any GPS device or app that produces standard GPX. Compatible with Garmin, Suunto, Wahoo, and all major platforms.
- [FIT] FIT file upload. Direct upload of FIT files from Garmin and compatible devices.
05. Access
Registry
Free Access
Marilyn Database
Browse all 1,550 Marilyns with summit coordinates and prominence data.
Current Records
Real-time synchronisation for all future ledger entries.
Archive
Annual Access — 7-day free trial, then auto-renews at £24.99/year unless cancelled
Historical Coverage
Full historical synchronisation for eligible activity history. Existing Strava activities are audited against all 1,550 Marilyns.
Verification Ledger
Full record of verified and unverified Marilyn ascents with activity source and date.
Reversion Policy
If annual access lapses, visibility reverts to free-window policy.
Start 7-Day Free Trial
7-day free trial for eligible new subscribers. After trial, subscription auto-renews at the standard price of £24.99/year unless cancelled.
Download on the App Store →06. Frequently Asked Questions
What is a Marilyn?
A Marilyn is a hill in Great Britain with a topographic prominence of 150 metres or more, regardless of absolute height. There are 1,550 Marilyns across England, Scotland, and Wales.
Can a Munro also be a Marilyn?
Yes. Any Munro with 150m or more of prominence is also classified as a Marilyn. Many Munros qualify under both lists. Northing tracks each list independently.
Does Northing cover all 1,550 Marilyns?
Yes. The database includes all 1,550 current Marilyns across Great Britain with summit coordinates.
Does Northing work offline?
Northing performs verification post-hoc. It does not track you in the field. An internet connection is required to import activities and view your ledger.