[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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