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Planet: Imaging the entire Earth every day

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Re: Planet: Imaging the entire Earth every day

#121

Post by jofer »

RosanaAnaDana wrote: post #107
dougmwne wrote: post #79

Earlier quoted context omitted.

No way, not even close. At this point Google is doing overhead lidar flights to get incredibly details 3d maps. The Planet imagry is like going back several decades in satellite tech. But on the other hand, it's daily.

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?).

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

#122

Post by schoen »

carapace wrote: post #112
tunesmith wrote: post #29

I can't believe I've never wondered this before, but I wonder how possible it is to deliberately create a satellite-blocking cloud above one's own property. What height and size it would have to be, etc.

Geodesic dome, cheaper and more durable. As added bonus it protects you from the heat. One day we will likely dome cities: https://en.wikipedia.org/wiki/Old_Man_River%27s_City_project

One of the uses of a radome (https://en.wikipedia.org/wiki/Radome) is to conceal the appearance of the antenna inside, so that people photographing it can't learn what frequency and direction it targets. That includes by satellite photography.

I don't think it would be very pleasant to have a radome over your house or yard, though, since you usually want sunlight to come in!

Re: Planet: Imaging the entire Earth every day

#123

Post by branchan »

jofer wrote: post #121
RosanaAnaDana wrote: post #107

Earlier quoted context omitted.

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?).

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…

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

#124

Post by shpx »

patrickyeon wrote: post #105
crazygringo wrote: post #92

Super cool! I wonder why both clouds and ocean show up as black instead of as actual white and blue imagery respectively. Are they saving money and bandwidth by not sending back "useless" imagery? Or something else?

(I used to work at planet, this is my recollection of what was the case then) Usually, for ocean-sized bodies of water, we'd stop imaging entirely to reduce power load and align the solar panels with the sun. Effectively all of the ocean had nothing going on on the surface that we could image anyway. When Planet gets the imagery, they have a fairly good sense of where it is, but it is still processed to get it to ali…

You could track container ships, in fact they're probably so easy to detect you could run a small computer vision model on the satellite and only transmit those photos.

Obviously the most interesting container ships are the ones that you can see from space but don't show up on marine trackers. Although I don't know how you turn that information into money.

Actually someone must already be doing this, Airbus sponsored a Kaggle competition for detecting ships in satellite imagery https://www.kaggle.com/c/airbus-ship-detection and maybe that's how they caught that Iranian oil tanker last month.

Re: Planet: Imaging the entire Earth every day

#125

Post by branchan »

samirm wrote: post #110

I hope they start imaging at least parts of the ocean, like the great pacific garbage patch and other areas of particular interest for meteorologists and environmentalists.

You can't see the garbage patch from space.

https://www.nationalgeographic.com/news/2018/03/great-pacifi...

Re: Planet: Imaging the entire Earth every day

#126

Post by branchan »

haditab wrote: post #32
mbrumlow wrote: post #30

Earlier quoted context omitted.

If you could track the satellite could you not shine a laser, or bright light (maybe a mirror reflecting the sun) directly at the camera to mess up the imaging while over your region?

And if an aircraft flies over your property you could get charged with a federal offense (pointing a laser at an aircraft).

This would be rare and it would only affect the pilot if the laser was tracking the plane as it flew overhead.

Re: Planet: Imaging the entire Earth every day

#127

Post by jofer »

branchan wrote: post #123
jofer wrote: post #121

Earlier quoted context omitted.

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…

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.

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

#128

Post by Rebelgecko »

dougmwne wrote: post #64

You can access their monthly imagery for free by creating an account at planet.com. I use it to track the progress of infrastructure and other land development projects near me. You can also create time lapse animations of a particular area, which is a super fun way to watch a road or a highway being built.

I thought they EOL'd the free offering?

Re: Planet: Imaging the entire Earth every day

#129

Post by Rebelgecko »

shpx wrote: post #124
patrickyeon wrote: post #105

Earlier quoted context omitted.

(I used to work at planet, this is my recollection of what was the case then) Usually, for ocean-sized bodies of water, we'd stop imaging entirely to reduce power load and align the solar panels with the sun. Effectively all of the ocean had nothing going on on the surface that we could image anyway. When Planet gets the imagery, they have a fairly good sense of where it is, but it is still processed to get it to ali…

You could track container ships, in fact they're probably so easy to detect you could run a small computer vision model on the satellite and only transmit those photos. Obviously the most interesting container ships are the ones that you can see from space but don't show up on marine trackers. Although I don't know how you turn that information into money. Actually someone must already be doing this, Airbus sponsored…

Planet & others are listening to AIS transponder signals from space which I imagine takes out a lot of the need for a bandwidth-heavier computer vision approach. Ships turn off their AIS sometimes when they're doing naughty things, but from what I understand they're usually relatively close to shore when they do that.

Re: Planet: Imaging the entire Earth every day

#130

Post by nico »

Really cool visualization!

Talking about visualizing Earth. Does anyone know of alternative visualizations/projections of Earth (other than globes and maps)?

For example, what would it look like if we could image Earth, entirely, from pole to pole, continuously, like a panoramic picture? (imagine the result as an impossibly wide picture that starts with one pole on the left and ends with the opposite pole on the right)

Thank you.

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