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How Google Earth Images Are Made

Posted by Zonk on from the it's-all-in-the-f-stop dept.

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.'

5 of 122 comments (clear)

  1. Some tiles too dark by Derling+Whirvish · · Score: 5, Insightful

    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.

  2. Most people don't think. Period. by EmbeddedJanitor · · Score: 5, Insightful

    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.

    --
    Engineering is the art of compromise.
  3. We? by EmbeddedJanitor · · Score: 5, Insightful

    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).

    --
    Engineering is the art of compromise.
  4. Re:Oops - my bad by Eivind · · Score: 4, Insightful
    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.

  5. Re:Oops - my bad by Proofof.+Chaos · · Score: 3, Insightful

    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.