On Fri, Jan 1, 2010 at 11:49 PM, John Smith <deltafoxtrot...@gmail.com>wrote:
> 2010/1/2 Aun Johnsen <li...@gimnechiske.org>: > > Even if you have access to good arial photography, remember that it might > be > > out of alignment, it can be a good advise to gather some good fixes to > check > > the alignment of your photos, this can be several GPS tracks along your > > trail. > > I'm pretty sure the imagery he's refering to is nearmap.com, which I'm > not sure how they manage it exactly but they seem to be about > sub-metre accuracy... > Than they have done a hell of a job on aligning the fotos, cudos to them. I know that Yahoo imagery varies from less then 1 meter to at least 30 meters on the hi-res, havn't seen nearmap, and as I understand its only for Australia, so I would not have any data to compare with. As far as I know IALA have coverage also in Australia, and I am sure that you can get HF also, though it might inicate stations far away (IALA have a range of about 150km, HF roughly 1000km), these two systems are focused on shipping, so I would guess augmentation stations and transmitters are located along the coast. So saying that Australia have no augmentation systems are plain wrong. Now the question is rather if your handheld device supports IALA.
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