"A 1995 survey by David Crystal of the usage of /a
ː/ ("long a") and /æ/ in the same words ("graph", "chance", "demand", "dance", "castle", "grasp" and "contrast", across five cities, found that /a
ː/ was generally strongest in
Adelaide, where it was used on average 88% of the time, and weakest in
Hobart at 39% "(Crystal, 1995,
Cambridge Encyclopedia of the English Language).
But it's more of a free variation, and not simply geographically determined. Most people in Queensland, including me, say /daens/.