[103730] in North American Network Operators' Group
Re: Dubai impound ships suspected in cable damage
daemon@ATHENA.MIT.EDU (Alexander Harrowell)
Sun Apr 13 07:54:30 2008
Date: Sun, 13 Apr 2008 12:47:43 +0100
From: "Alexander Harrowell" <a.harrowell@gmail.com>
To: Valdis.Kletnieks@vt.edu
Cc: "Joel Jaeggli" <joelja@bogus.com>, "Patrick Giagnocavo" <patrick@zill.net>,
nanog@nanog.org
In-Reply-To: <16268.1207892694@turing-police.cc.vt.edu>
Errors-To: owner-nanog@merit.edu
------=_Part_7154_11395407.1208087268429
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit
Content-Disposition: inline
Lots - for values of lots including "practically all" - of ships use the AIS
(Automatic Identification System), which broadcasts various details on
radio. For an example application, try www.aisliverpool.org.uk
On Fri, Apr 11, 2008 at 6:44 AM, <Valdis.Kletnieks@vt.edu> wrote:
> On Tue, 08 Apr 2008 22:16:57 PDT, Joel Jaeggli said:
>
> > spot can generally deliver an image within 1 day in 60kmx60km blocks
> > assuming no contention for the slot. 20m resolution is more than
> > adequate to pick up ships underway at sea. ikonos can deliver 11x11km
> > swaths.
>
> And ikonos can do a lot better than 20m resolution. We had ikonos target
> the campus for a special event a few months ago:
>
> http://glovis.geog.vt.edu/hokiesthanktheworld/
>
> "The full extent of the satellite image is approximately 100-square
> kilometers,
> stretching from Brush Mountain (upper left) across Blacksburg (center) to
> Ellett Valley (lower right). The Virginia Tech Drillfield is located near
> the
> center of this November 17, 2007 scene from the GeoEye IKONOS satellite.
> This
> true color rendering by Peter Sforza combines red, green, and blue
> wavelengths
> (3.7-meter pixels) into a RGB color image, and sharpened using the
> panchromatic
> band (0.92-meter pixels). Note the sun's angle of elevation was 32 degrees
> and
> the azimuth was 164.1 degrees (north being zero)."
>
> 1-meter pixels sounds about right - if you look at the right place on the
> full-scale image, you can find (and tell the difference between) my dark
> green
> Camry, and the immediately adjacent dark grey Nissan my neighbor drives,
> and
> still see 3 feet worth of parking lot pavement in between them too...
>
> Not bad for 423 miles up and moving at 4.7 miles per second....
>
>
>
------=_Part_7154_11395407.1208087268429
Content-Type: text/html; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit
Content-Disposition: inline
Lots - for values of lots including "practically all" - of ships use the AIS (Automatic Identification System), which broadcasts various details on radio. For an example application, try <a href="http://www.aisliverpool.org.uk">www.aisliverpool.org.uk</a><br>
<br><div class="gmail_quote">On Fri, Apr 11, 2008 at 6:44 AM, <<a href="mailto:Valdis.Kletnieks@vt.edu">Valdis.Kletnieks@vt.edu</a>> wrote:<br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<div class="Ih2E3d">On Tue, 08 Apr 2008 22:16:57 PDT, Joel Jaeggli said:<br>
<br>
> spot can generally deliver an image within 1 day in 60kmx60km blocks<br>
> assuming no contention for the slot. 20m resolution is more than<br>
> adequate to pick up ships underway at sea. ikonos can deliver 11x11km<br>
> swaths.<br>
<br>
</div>And ikonos can do a lot better than 20m resolution. We had ikonos target<br>
the campus for a special event a few months ago:<br>
<br>
<a href="http://glovis.geog.vt.edu/hokiesthanktheworld/" target="_blank">http://glovis.geog.vt.edu/hokiesthanktheworld/</a><br>
<br>
"The full extent of the satellite image is approximately 100-square kilometers,<br>
stretching from Brush Mountain (upper left) across Blacksburg (center) to<br>
Ellett Valley (lower right). The Virginia Tech Drillfield is located near the<br>
center of this November 17, 2007 scene from the GeoEye IKONOS satellite. This<br>
true color rendering by Peter Sforza combines red, green, and blue wavelengths<br>
(3.7-meter pixels) into a RGB color image, and sharpened using the panchromatic<br>
band (0.92-meter pixels). Note the sun's angle of elevation was 32 degrees and<br>
the azimuth was 164.1 degrees (north being zero)."<br>
<br>
1-meter pixels sounds about right - if you look at the right place on the<br>
full-scale image, you can find (and tell the difference between) my dark green<br>
Camry, and the immediately adjacent dark grey Nissan my neighbor drives, and<br>
still see 3 feet worth of parking lot pavement in between them too...<br>
<br>
Not bad for 423 miles up and moving at 4.7 miles per second....<br>
<br>
<br>
</blockquote></div><br>
------=_Part_7154_11395407.1208087268429--
