I think my height map is working and i can create a depression i think it was just because i created it in an empty level i thought that there was none 
here is a shot of map and also depression/ elevation relative to a landscape which hasn’t been edited
however is method of using several landscapes to make a planet feasible in a game where there may be 100+ planets, each one you must be able to zoom into on scale to view a tree say a tree, and each planet must be large i.e. a reasonably close representation of a tree relative to earth ?? does a landscape that is far away reduce in memory usage? i.e. is landscape created and LOD reduction from an algorithm and created
on spot relative to where character is ?? or is landscape created and reduced from mesh from memory ??
thanks