How Google Earth Images Are Made

An anonymous reader writes "The Google Librarian Central site has up a piece by Mark Aubin, a Software Engineer who works on Google Earth. Aubin explains some of the process behind capturing satellite imagery for use with the product. 'Most people are surprised to learn that we have more than one source for our imagery. We collect it via airplane and satellite, but also just about any way you can imagine getting a camera above the Earth's surface: hot air balloons, model airplanes - even kites. The traditional aerial survey involves mounting a special gyroscopic, stabilized camera in the belly of an airplane and flying it at an elevation of between 15,000 feet and 30,000 feet, depending on the resolution of imagery you're interested in. As the plane takes a predefined route over the desired area, it forms a series of parallel lines with about 40 percent overlap between lines and 60 percent overlap in the direction of flight. This overlap of images is what provides us with enough detail to remove distortions caused by the varying shape of the Earth's surface.'

Not always so high tech

[BandwidthHog]

A friend of mine is a local flight instructor and has done a few flights for Google Maps crew. Perhaps they were just doing specialized by-request work, but in this case it was a dude with an SLR and a big lens shooting out the window of a Cessna.

I was skeptical too, but that’s what he tells me.

Blurred residences on Google Maps in Lexington, KY

[Anonymous Coward]

4275 Athens-Boonesboro Road, Lexington, Kentucky 40509

Seems an appropriate opportunity to ask the question: Why the fuck is this residence blurred out? It appears to be someone who is a planholder in Kentucky's state health care plan, so maybe they're a powerful state government official:

http://www.google.com/search?hl=en&client=safari&r ls=en&q=4275-athens-boonesboro&btnG=Search [google.com]

BTW, why are the addresses of all Kentucky state planholders publicly available and indexed on Google? That is just pathetic data security...

Anyway, the same address is accessible (and not blurred) via Microsoft Live!:

http://maps.live.com/default.aspx?v=2&cp=q9wwps7yy j8t&style=o&lvl=2&tilt=-90&dir=0&alt=-1000&scene=2 023607&encType=1 [live.com]

And appears to show two residences with pools in the back yard. Nothing to hide. Property records indicate that they were formerly owned by a lawyer named William Hurt, who practices in Lexington but now lives at another address. Given the rather inconspicuous pictures of them at the Microsoft Live flyover, the fact that they're blurred out on Google Maps is even more conspicuous than just showing the pictures of the two houses that are blurred.

There may be a high-powered state government official living there, but how did they have enough influence to get the pics blurred out? Were they skinnydipping in the pool? I don't think the map would show enough detail to make that a problem. Any ideas?

Earth is one big billboard

[BillGatesLoveChild]

Google Earth used to be cool, but it's turning into one massive billboard (perhaps one of the ideas all along). In Sydney for Australia Day, Google (and whatever the Microsoft's copy of it is called) did flyovers with huge pre-publicity. People lay out banners, .com wannabees stuck huge logos on their rooves, people picnicked and love-maked all on the hope of becoming 'famous' (with four million other people). Google put it up and at the end of the day, Sydney wasn't Sydney any more. Instead, Sydney was transformed into one big banner ad:

http://googlesightseeing.com/2007/02/27/australia- day-flyover/ [googlesightseeing.com]

Then we had the world's biggest photojournalism fakery with Google restoring New Orleans to pre-Katrina. Beyond weird. Did they think the residents wouldn't notice?

http://www.theregister.co.uk/2007/04/02/new_orlean s_demolished/page2.html [theregister.co.uk]

Google Earth is sponsored infotainment. If you'd like to see Earth without the Ads, there's a little mob called NASA I hear are going places: http://visibleearth.nasa.gov/ [nasa.gov]

They use a film camera???

[gsasha]

I'm extremely surprised they don't use a digital camera these days. Digital has great quality, and a full-frame digital back of the likes of Mamya, while expensive, pays for itself very quickly if you shoot a lot (and they appear to be doing so continuously). Besides, there would be no need to develop the film and scan it.

Any ideas why they do so?

Gov't conspiracy or smudge?

[Anonymous Coward]

Yes, it certainly could be a government conspiracy of some kind. Or it could be a spot of oil on the film. But the conspiracy idea is so much more fun.

http://www.boingboing.net/2006/09/28/google_maps _reveal_w.html

Re:Most people don't think. Period.

[DerekLyons]

Anyone who has thought about this for more than half a second, or has looked at anything more than just their backyard would realise that it is cobbled together from various sources.

Not only that, but the article strongly implies that Google itself is obtaining the imagery - which is not the case. They buy (or license) imagery from a wide variety of sources. (The folks who take these images tend to retain the rights to them - and resell the imagery as many times as possible.)

Re:They use a film camera???

[eggegg]

I thought film was dead too (or rather, I thought it should be), until we recently had to order 40k acres of imagery at six-inch-pixel resolution, and I talked with the folks who own the cameras and fly the planes.

When it comes to airplane-based commercial aerial photography, film remains the most wide-spread capture medium. A decent camera can easily cost more than $1 million -- and you'll probably want two to capture stereo pairs, and don't forget a spare. For now, digital cameras are no less expensive and offer few benefits over their film-based bretheren.

Both require a GPS-controlled platform, capable of shooting several shots a second. After scanning, typical film-based photography is for all intents and delivers a 250+ megapixel result -- the digital alternative to such a beast is not exactly easy to find, and definately not inexpensive. Those are big files tool, and lossy compression is a bad, bad thing. Given the cost of fuel these days, redundancy is essential when it comes to data. That means being able to store four-to-twelve uncompressed (or minimally) 250+ megapixel images on two systems of one type or another, both of which must be rugged enough to withstand their environment.

Last but not least are the lenses. Outside the world of physics research, the highest quality land-camera lenses, even those in the cinematagraphic world, exhibit far more distortion than is acceptable for survey-grade aerial photography.

So, you're right. And yes, it sucks. We're betting environmental regulations will probably be the nail in the coffin over the next decade.

Re:Most people don't think. Period.

[Bob-taro]

Dude, you find the oddest shit to be all superior about.

Well put. If a story came out that ... I don't know ... Osama Bin Laden was once a woman, you can bet someone would post "Am I the only one to whom that wasn't patently obvious?"

The funny thing is, the "patchwork" appearance of less populated areas on Google earth is probably NOT evidence of the photos coming from different sources. You can get very high resolutions [wikipedia.org] from satellite imagery. I always assumed the low-res areas were due to storage limitations of Google's servers - I mean, why store detailed images of every square mile of the pacific ocean?