Hi Dave, I have two completed maps with same layer data, base altitude, meters per interval . Both maps have same width.I have saved then "calculate terrain " then saved as cache. I re-sized one map to enable the second map to fit on top by increasing new height to sum of map one + map two. I repositioned map first map using the X , Y co-ordinates ( Y = 5000 , The map being imported is 5000m high ) . So I have map 1 originally 10000m high, now it is 15000m high and the blank space is on the top, all good so far. I have both maps open , I select map 1 and click " import map" , a dialogue box appears with map 2 in it, I click import , nothing happens. I have re-traced my steps and checked I have done everything by the book.