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How Google Earth Images Are Made 122

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.'
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How Google Earth Images Are Made

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  • by Derling Whirvish ( 636322 ) on Sunday April 29, 2007 @10:55PM (#18923437) Journal
    I sure wish Google Earth had a way to adjust the brightness/contrast of individual tiles or maybe the view window. Some areas are very dim and need brightness/contrast adjustments.
  • by EmbeddedJanitor ( 597831 ) on Sunday April 29, 2007 @10:56PM (#18923439)
    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.
  • We? (Score:5, Insightful)

    by EmbeddedJanitor ( 597831 ) on Sunday April 29, 2007 @10:59PM (#18923469)
    This makes it sound like Google actually did this work themselves with mental images of Googlites flying kites and riding hot air balloons. That is patently untrue. Most of the images in Google earth have come from other sources (government agencies, scanned aerial photos, etc).
  • Re:We? (Score:2, Insightful)

    by stoicio ( 710327 ) on Sunday April 29, 2007 @11:30PM (#18923669) Journal
    Yes, I agree. There are huge glossing statements that make
    it sound like google actually acquires data.
    This engineer has only a vague idea of how airborne and satellite
    imaging work.
  • by Anonymous Coward on Sunday April 29, 2007 @11:33PM (#18923681)
    You missed the point, genius.

    Google does more than just stitch the images together. The seemingly excessive overlap is used not only to stitch, but to correct for geometric errors of perspective.

    Somehow, I doubt your camera does that too.

  • Re:Oops - my bad (Score:2, Insightful)

    by Anonymous Coward on Monday April 30, 2007 @12:37AM (#18923979)
    Things are very bad. When was it ever a problem to be taking pictures near a school? In 2000, I worked with a photographer who did freelance work for a local newspaper. He related a story to me about being "hassled" by the police a few years earlier. He parked outside of an elementary school while waiting for his kids to get out. He grabbed his camera and started photographing some of the trees in the area, as it was Autumn and very colorful in the area. Which almost always gets printed in the paper for a small sum.

    When he returned to his car to wait the last few moments for the school to let out, he had a few cops pull up. They approached him. They asked for his ID, which was in his car, but they would not let him approach his car. They questioned him with a very gruff attitude. They made a few threats to him, and they were very unruly. After ten minutes they finally told him why they were harassing him. One of the teachers in the school saw him pull up and and leave his car with a camera. The cops went a bit overboard with him. They did not allow him to identify himself by allowing him to approach his car.

    This "Think of the Children" thing was going to far back then, and it is out of control now.

    A person can walk on the public streets with a camera and take pictures of anything they want. So what if they are near a school or a powerplant. If you want to watch that person, then so be it. But they should still have the freedom to do that. They were not infringing upon the freedom of anyone else, they broke no law. This country needs to realize that The Constitution does not grant you the right to be happy, or to not be offended or annoyed.
  • Re:Oops - my bad (Score:5, Insightful)

    by Eivind ( 15695 ) <eivindorama@gmail.com> on Monday April 30, 2007 @02:50AM (#18924595) Homepage
    Perhaps, but one problem is that its the same people who are "suspicious" every time, so what may seem reasonable to all outsiders, because whatever behaviour looks fishy, may be a constant nuisance of having to defend ones own perfectly legal actions over and over and over to cops.

    I know a guy, originally from Pakistan, wears typical street-kid clothing, is passionate about biking and have a $10K bike.

    He *literally* has to "explain himself" once a week or more.

    By the 20th time a cop pulls you over and demand that you explain how the hell you're allowed to ride a bike that you, infact, own, you tend to stop thinking that its all that reasonable.

    The problem offcourse is that each individual cop doesn't know that X other cops *also* pulled the guy over this year, so to them it seems reasonable and so its hard for them to see why he can be annoyed and impatient about it.

  • by Proofof. Chaos ( 1067060 ) on Monday April 30, 2007 @05:59AM (#18925435)
    There's nothing to see in the Sahara. No wonder nobody has taken hi-res photos of it.
  • Re:Oops - my bad (Score:3, Insightful)

    by Proofof. Chaos ( 1067060 ) on Monday April 30, 2007 @06:17AM (#18925511)

    We had a policeman knock on our door a few years ago. A car vaguely matching the description of ours was seen leaving the scene of a grass fire. He was quite friendly, explained why he was there, asked if we'd been anywhere recently (I assume he would have put his hand on the bonnet of the car too just to check), chatted about the weather, and then left. Just the way it should be.
    You're right, that's "Just the way it should be."

    I assume you're from the UK, because you used the word "bonnet." I've heard about your friendly neighborhood constables. Unfortunately, in the US, most (not all) cops are on a power trip, and are more interested in harassing whomever they have an excuse to harass, than gaining the respect of the (generally) law abiding public, and preventing real crime.
  • Idiot (Score:3, Insightful)

    by Snaller ( 147050 ) on Monday April 30, 2007 @09:06AM (#18926591) Journal
    "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?"

    No, they thought they were intelligent adults instead of idiots. Nowhere in the world is the completely correct (surely not around here) BECAUSE ITS NOT REAL TIME. They get the best quality which is fairly close. Those of us with 3 digit IQ's understand that.

    "Google Earth is sponsored infotainment. "

    Indeed, if you want to find a pizza place you can do it fast.

    "If you'd like to see Earth without the Ads,"

    You just use Google Earth since no adds pop up.

    " there's a little mob called NASA I hear are going places: "

    Not in the real world, they could never afford to make it a worthwhile program.
  • Re:Oops - my bad (Score:1, Insightful)

    by Anonymous Coward on Monday April 30, 2007 @10:35AM (#18927489)
    list of registered sex offenders

    Let's not even get into how wrong that is.

    I mean if they served there time, then they should not still be treated as criminals afterwards. If they are not "rehabilitated", then they should not be let out, at least not out with the general public.

    I know, I know, prison is not a place of rehabilitation. And of course, since they have been to prison they can no longer participate in elections (except as candidates), which means no one will listen to them when they could possibly help in one way or another.

    One more thing: It should not be easy to be a cop. They should be more righteous than the general public. They should have to jump through a great number of hoops. All to make sure they do not go overboard and harass or infringe on an individuals rights. That is the price of being a cop.

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