[Talk-us] HI: Hawaii GIS Data
Scott Atwood
scott.roy.atwood at gmail.com
Sat Dec 5 19:29:42 GMT 2009
On Dec 5, 2009, at 4:02, "David ``Smith''" <vidthekid at gmail.com> wrote:
> On Fri, Dec 4, 2009 at 7:47 PM, Scott Atwood <scott.roy.atwood at gmail.com
> > wrote:
>> Offshore islets can probably be mapped via satellite imagery.
>
> It's common practice for providers of aerial/satellite imagery such as
> Yahoo to mask out actual coverage of oceans and large lakes with a
> generic "ocean" texture that is meant to look "better" than actual
> photographic data. So if it's small and not very close to the
> mainland, don't count on it showing up in the Yahoo imagery.
Ah! Thanks for that explanation! I had already noticed some of the
more isolated islets in the northwest Hawaiian islands were
mysteriously missing from the Yahoo images and aren't in the PGS data
either.
However, I was mostly referring to the numerous small islets within a
few hundred meters of shore. Most of these don't seem to be in PGS,
but so appear in the Yahoo images, though not necessarily at a very
high resolution. The GIS data should give good coverage of these
islets near the main islands.
-Scott
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