Google's GeoEye-1 Takes Its First Pictures

Kev92486 writes "I was scanning through my RSS feeds today and happened upon an article about Google's GeoEye-1 imaging satellite which launched on Sept 6. Intrigued as to what the quality of the image was like, I decided to check it out only to find that the first picture was actually of my college campus, Kutztown University (Pennsylvania).
I had to make sure I was reading the article correctly as Kutztown is not a very large or well known campus. I'm not sure as to why they chose Kutztown for their first pictures. I would be interested if anybody could provide some sort of insight as to what process was used to select the first test location. Was the satellite simply in a convenient orbit to snap pictures of Kutztown?" Update: 10/09 20:56 GMT by T : HotHardware has its own article up on GeoEye-1, if you'd like your words and pictures in the same place.

Waiting for Green Bay

[ckotchey]

Even more curious to me is why Google Earth still has such a low-res image of Green Bay, WI (Packers!!), but I can see Cochranton, PA (population: a few dozen or so) clear as crystal. Go figure.

Re:not impressed with orbit

[SpleenVenter]

Sun-synchronous orbits are extremely common for optical imaging satellites. A sun-synchronous orbit simply means that the satellite crosses the equator at a specific time of day on every orbit. The sun-synch time can be chosen at will; you can make it any time that you want. If you choose noon, you get very short shadows; if you choose a time early or late in the day, you'll get long shadows. The length of the shadows at any give spot the Earth (away from the equator) changes with the season (because the sun's relative angle changes as the Earth orbits the sun).

Shadows are actually a useful artifact when you're doing imagery analysis, and that's part of the reason that away-from-noon descending nodes are chosen. 10:30 is a popular time because it gives shadows that are "just right" -- not too long and not too short. Note that a 1:30PM orbit would theoretically be an equivalent (and symmetrical) choice -- but for practical purposes a morning orbit is a better choice: there are statistically fewer clouds in the morning over most of the planet compared to the afternoon. Also note that a "10:30" orbit means "10:30 at the equator". It's a bit earlier than this in the northern hemisphere, and a bit later for the southern -- but it's always at the *same* time of day.

Re:What a letdown

[SpleenVenter]

Do you have any idea of how expensive it is to collect aerial photography over large areas? Sure, 6-inch imagery is great. Who's going to pay for it? --and how do you collect it over, say, China? The Earth has just under 150,000,000 sq. km. of land surface area -- do you realize how long it would take to collect the Earth even ONCE from an aerial platform?

Bottom line: there are good practical reasons why you won't see 6-inch imagery of the whole planet any time soon.