Hole 4

The green · from the map

Centre, front and back are measured; the caddie in the app reads the same three points. Green depth 28 m along the line of play.

The ground · from open elevation data

Tee 6 m above sea level, green 7 m. Uphill is played as the distance plus the climb; downhill as the distance minus two thirds of the drop — the rule caddies used before rangefinders, and near enough on a still day. Sampled every ten metres along the line of play from Copernicus DEM GLO-30, a thirty-metre model of the whole world, accurate to about 4 m. It reads the top of what is there, so a tree-lined tee can read high. Copernicus DEM © DLR/Airbus, provided under Copernicus by the European Union and ESA. The same numbers are in the open data.

Tap any number to go there.

On the tee

Distance to this green, live, from where you stand.

YŪGEN reads the same green — front, centre, back — and tells you the number as you walk. Free.