I don't know. It is irrelevant, but NSN-AKL is indeed mostly over water. A bit hard to tell from
GCM, but in my experience is basically over land only at Taranaki, and Pukekohe/Waiuku area (possibly also Manukau depending on runway direction being used). The rest is over Cook Strait, just off the North Island west coast, and over Manukau Harbour.