A group of wind turbines were constructed at Gravely Cambridgeshire UK around 5km from my home and have been mapped by Great Britain’s Ordnance Survey, It took a couple of years for them to map them which was quick, for them. Note our OSM openstreetmap was purposely similarity named to promote it, that was how I discovered osm within a year or so of it’s creation by Steve Coast. I looked at OSM and noticed the turbines had not been mapped, how could I plot them? ( without copying from the Ordinance Survey Map). The turbines are by private ground and most are at least a kilometre from any public access. I gave the problem some thought and looked at the area and noticed that from some directions the turbines were in two lines of 4. I now had a plan I would position myself and my gps on these lines in turn and plot four points, that would give me two lines that the turbines could be plotted along. I used field papers and printed the map so i could sketch the rough layout and take notes. I used my Garmin Oregon 450 and recorded 12 waypoints at positions along the surrounding roads where either four or two turbines aligned. Using Potlatch2 the plan was to join pairs of the waypoints with an untagged way then do the same with a cross pair, the intersection of the two ways should be where a turbine could be plotted. The untagged ways were then deleted. I repeated the process for the eight turbines, job done. I checked ( and only checked) against OS.All my results were within 40 meters most within 10 meters of OS. THEY could be wrong!! The downside is you can only see them in an editor as none of the Map Page maps render them…yet.