Blog
How we map UK golf courses
12 August 2026
Course data is the least glamorous part of a golf GPS app and by far the hardest. A distance is only as good as the coordinates behind it, and there is no single tidy database of British golf courses to buy.
Here is how we built ours.
Starting with open data
The foundation is OpenStreetMap. Volunteers have traced an enormous amount of golf course geometry over the years, including fairways, greens, bunkers and tee boxes, and it is openly licensed.
That gets you a long way. It does not get you all the way. Coverage is uneven: some clubs are mapped hole by hole with every bunker in place, and some are a single outline round the perimeter with nothing inside it.
Working out what is trustworthy
Raw data you have not checked is worse than no data, because it looks authoritative. So every course goes through a validation pass and comes out sorted into tiers:
- Verified — hand-checked, or cross-referenced against an independent source that agrees on the par and the per-hole layout.
- Fully mapped — tees, greens and pars all present, and every automated check passed.
- Partially mapped — hole data exists but something looked off, so it is flagged and the app tells you how many holes it actually has.
- Outline only — we know the course exists and where it is, but there is no per-hole data yet. The app says so plainly rather than showing a confident number it invented.
Roughly two thirds of British courses are currently in that last group. We would rather tell you that than pretend otherwise.
The direction problem
One bug is worth describing, because it shows how these things go wrong.
To calculate a hole you need to know which end is the tee and which is the green. Our first approach worked outward from the middle of the course. It was subtly wrong on any course that doubles back on itself, which is a lot of them, especially the older ones squeezed onto a small site.
At one club this produced a course measuring 5,246 yards. The real figure is about 6,700. Every hole on it was short, consistently, and it looked plausible enough that it took a while to spot.
The fix was to stop guessing from the centre and anchor each hole to the green nearest each of its ends. After re-running the whole pipeline, more than a hundred courses moved up a tier.
What gets mapped next
This is the part players control. When you tell the app which courses you play, that goes into a queue, and the courses the most people have asked for get filled in first.
It replaced the previous system, which was, honestly, whichever course happened to be nearest to where we live.