Power Lines Map

What the map shows

Every orange line is a transmission line, the big routes carried on steel pylons, and every yellow line a distribution line, the smaller lines carried on poles across fields. Close in each cell is about 10 metres, and any cell a line crosses at all is marked, so a line is an unbroken band however it runs; where the two meet, the transmission line is shown. Lines mapped as underground are left out, since they are no hazard to anything landing on top of them. From zoom 14 in, every pylon shows as a white dot on its line.

Zoomed out, each pixel covers many cells, so every line is drawn in one orange, strong enough to stay in view however thin the line is.

Pylon heights

Where OpenStreetMap records a pylon's height, that is used. Most pylons have none recorded, so their height is estimated from the voltage of the line they carry: about 50 metres for 380 kV and above, 45 metres for 220 kV and above, 30 metres for 110 kV and above, 22 metres for 60 kV and above, 15 metres for 30 kV and above and 12 metres below that, and 30 metres where the voltage is not known either. Estimated heights are marked as such on the map and in the data. Lines hang between the tops of their pylons and sag lower between them, so the pylon height is the most the wires can reach.

Where the data comes from

The lines and pylons come from OpenStreetMap, the open map of the world, through the regional extracts Geofabrik publish. Transmission lines are well mapped in most of the world; distribution lines are well mapped in some countries and patchy in others, so a line missing from the map is not proof there is none.

Why a rocketry site maps power lines

A rocket or parachute caught on an overhead line cannot be recovered safely: it needs the line's operator, and it can cut the power to everyone along it. Lines often cross exactly the open farmland clubs fly from. Knowing where they are around a launch site, and how high their pylons stand, shows which way the drift must not go and how far downwind a launch must be kept.

The same data is going into the Altimeter Cloud Landing & Radio tool and the 3D site map, where the lines will hang between their pylons at height.

Use the data in your own projects

Everything on this map is available through the free Power Lines API, no key needed: any square up to 30 km across around a point, every cell as its line class in two bits, and every pylon with its height, voltage and whether the height is estimated, as JSON or as small binary files a flight computer can carry. The download panel on the map does the same thing from here.