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Originally Posted by Fryguy
I doubt Google Earth has the measuring capability, especially since most of the world uses meters. Just a thought, but those numbers may be put into the system. It's like saying PayPal has incredible fingerprinting technology. They don't. it's just your phone using its prescanned fingerprint to help you login faster through using other apps.
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Actually, Google Earth's imagery is accurate down to the foot. You can measure main roof parapets that are 1 to 2 feet tall and rooftop vents that are a foot tall. I'm noticing that the numbers that Google Earth has for buildings and site sea level elevations are exactly the same as the ones listed on building elevations that the architects, engineers, and developers use to build skyscrapers with. If Google Earth's data is accurate enough for them, then it's accurate enough for me. Even if they're not using Google Earth itself, they may be using the same data that Google Earth does. Google Earth gets their imagery from government satellites and then digitally renders the imagery to create 3D images.
I've been collecting building heights for 25 years and so far it's the most accurate method for gathering them that I've come across other than reading them straight off the building elevations. Even things like FAA permits and FCC permits have errors and people tend to round up numbers. And then there are typos. Also, what is shown on the building elevations that are approved by the city and what is ultimately built aren't always the same thing. Minor changes to rooflines and things like mechanical penthouses, mechanical screens, roof parapets or stairwell access sheds can increase or decrease building heights. More than once I've had to go back and measure a building's mechanical penthouse to get the true overall height of the building because they made a design change to the mechanical penthouse after the building was approved and the plans released to the public. Developers are also typically not required to file for new approval if their project decreases in size within what they had been approved for originally. Austin's Fairmont Hotel had originally been planned as a 50-story building. I have the building elevations of that version, but they changed the plan and chopped 15 floors and 100 feet off the height and completely changed the design. They did not need to resubmit their plans for that, and as a result, I don't have the building elevations for the current design that is being finished at the moment. I had ask for the building heights from the architect, and so far what I've been able to measure on the building with Google Earth, the numbers match what they sent me.