[talk-au] Coastlines from admin boundaries

[Darrin Smith]

On Tue, 14 Jul 2009 19:55:02 +1000
Matt White <mattwhite at iinet.net.au> wrote:

> I was just wandering around the Phillip Island area of Oz seeing how 
> things were shaping up, and noticed that the imported admin
> boundaries seemed to be a substrantially better example of the
> coastline when compared with the original PGS data - perhaps not
> perfect, but definitely better...
> 
> Which made me think that maybe we should have a crack at cleaning up
> the coast line now that we've got some decent data. Manually logging 
> coastlines accurately is a right pig - rocks are hard to trace around
> on foot, and you've pretty much got to do it during the equinox tide
> with the correct phase of the full moon up, at the high water mark
> while standing on your left left singing "Auld Lang Syne" in Aramaic
> to get it right... occurs to me that the ABS data that was imported
> is probably substantially better quality than we will ever get either
> with a gps or tracing off yahoo (some areas excepted).
> 
> But I wasn't sure if I should re-align the PGS way with the ABS admin 
> boundary way, or nuke the PGS way and tag the existing ABS boundary
> with the coastline tags, or just dance a jig. I know admin boundaries
> can change, but (global warming aside) the odds are pretty good those 
> boundaries set against coastlines probably aren't likely to change.

In a few spots where it's obvious the coastline has been traced of
landsat or derived from PGS and as you say the ABS is obviously of a
higher quality I have done the nuke non-ABS, tag ABS with coastline
(and often reverse to get the direction right) option a number of times.
About 99% of the boundary of Kangaroo Island fell into this category.

-- 

=b