Ahooi

BNG / Brittish National Grid projected Data in Google Earth / Bing etc (Web Mercator) using ESRI

Right so I’ve just wasted half a day on the web trying to get some data shifted for use in Google earth using ArcView. Nobody had a clear answer as to why I always had an offset / shift in data. There is a long answer which I won’t go into now, but here’s the solution to get around this:

Save your data in LAT/LONG first!
toolbox > datamanagement > projections and transformations > feature > project > geographic > OSGB1936

Now that it is in Lat Long you can convert to web mercator and apply a transformation. Applying a transformation is REALLY important. I found the petroleum one the be the best! So do the same steps, but project as > Projected > World > Web Mercator (Aux Sphere) and fill in the geographic transformation / choose the petroleum one from the drop down.

Now you can open it on the Bing basemap / export to KML

Have fun