Re:Planet: Imaging the entire Earth every day
by RosanaAnaDana on Wednesday August 14, 2019 @10:58AM
(#20696217)
Google imagery is a wide range of 10-100cm imagery. I believe (top of my head) that the planet data is natively 25 centimeters (7-8 band?).
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Re:Planet: Imaging the entire Earth every day
by jofer on Wednesday August 14, 2019 @01:08PM
(#20697568)
Planet global imagery is 4 band sampled at ~4m (oversampled to 3.0m). Skysats (Planet's high-res satellites) are 0.8m, but image only small areas. (Numbers are based on https://assets.planet.com/docs/combined-imagery-product-spec...)
Nothing is global at high resolution for anyone. Google's imagery is only high res at locations people are likely to look at.
High resolution satellites have a very narrow field of view. You can't image a large area with them. Ditto for aerial. There simply isn't 1m or better imagery globally, let alone 100cm.
Re:Planet: Imaging the entire Earth every day
by branchan on Wednesday August 14, 2019 @01:17PM
(#20697657)
I don't think that has anything to do with field of view. It's just that higher res = higher cost so they can't afford to have high res global coverage at LEO.
Re:Planet: Imaging the entire Earth every day
by jofer on Wednesday August 14, 2019 @01:28PM
(#20697796)
It really does have a lot do do with field of view. High res satellites fundamentally can't image a very large area (that's how a telescope works). They also usually can't image continuously. (High res means you can't image at the rate you're moving without significant SNR drawbacks - you have to stay pointed the target so that you have a long enough exposure time. You can get around this to some degree, but either way, high-res sats are designed for bursts of targeted imaging.)
You need _way_ more high-res sats than are currently in operation to image the entire land surface of the planet even yearly. So, yes, higher cost, but probably beyond what a company like google could pay. (Think trillions, not billions)
Re:Planet: Imaging the entire Earth every day
by Bedon292 on Wednesday August 14, 2019 @02:26PM
(#20698458)
To emphasize on this: WorldView 4, which has ~31cm pan imagery came to a cost of about $850M. And is the size of a school bus. Vs the significantly smaller and less expensive stalites Planet uses. And unfortunately that stallite had a failur and only was usable for a bit over 2 years. High res satellites are really hard still.
Re:Planet: Imaging the entire Earth every day
by RosanaAnaDana on Friday August 16, 2019 @11:12AM
(#20715942)
Yeah, I got my satellite companies confused. I was thinking of digital globe and their 31 cm offering (got a quote from them fairly recently).