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Why is the Gaza Strip blurry on Google Maps?

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Re: Why is the Gaza Strip blurry on Google Maps?

#171

Post by dragonwriter »

johnmcelhone wrote: post #139
Macuyiko wrote: post #89

Earlier quoted context omitted.

Since you know what you're talking about. Say I'm willing to accept the updated-daily or even weekly high-res imagery of the whole planet. Any idea what the cost would boil down to? How many parties are involved? Just wanting to learn more about this.

Want medium res (10m), Sentinel-2 imagery is your best bet. Won't cost you a penny. https://apps.sentinel-hub.com/eo-browser/ Looking for higher resolution (3m), the only viable option really is Planet. Even at that, they're pretty iffy with their pricing models and distribution. I think they range around the $2 per square kilometre mark.

for the whole planet, the jump between $0 and around $2/sq.km. is, what, $1 billion/update difference?

Re: Why is the Gaza Strip blurry on Google Maps?

#172

Post by csteubs »

caymanjim wrote: post #34
deadalus wrote: post #5

Is it possible to have real-time live-feed of the entire planet? If cost isn't an issue, would something like that be possible?

The short answer is no. High-resolution imagery comes from low-orbit satellites, which make a complete orbit about every two hours, and image long, narrow strips with each pass, taking days to image the whole planet. There are many of these satellites: commercial, non-military (publicly-accessible) governmental, and governmental (secret), of varying resolutions. These are also supplemented by aerial (plane) imagery.…

I'm the founder of a company working to solve this exact problem. Revisit rate of Planet's 200+ Dove satellites are quite good (multiple/day) but are comparatively low-res compared to their Rapideye satellites, of which there are fewer. There are a slew of others (Maxar is the next biggest name that comes to mind) but the thesis is low earth orbit is getting crowded, satellites are incredibly expensive even with off-the-shelf parts and falling launch costs, and hardware capabilities are locked-in at launch.

We're taking the approach of using "free energy" in the form of 100,000+ daily commercial/freight/general aviation aircraft to crowdsource aerial imagery using mobile phones to start. Passengers who opt-in are rewarded with free in-flight wifi (where equipped), and we use the device to do orthorectification and photogrammetry at the edge before transmitting it back down via satellite internet. I'm glossing over much of the actual process, but this frees up a ton of computing that would otherwise have to be done on the ground. In the event the flight is not internet connected, we cache previous images based on flight path and upload the difference after comparing old vs. new on the device once signal is restored. End result is a massive boost in both temporal and spatial resolution at a dramatically lower cost. Think Google Maps, updated every few minutes.

We're on IG @notasatellite if you're interested in looking at some samples.

Re: Why is the Gaza Strip blurry on Google Maps?

#173

Post by vinhboy »

gruez wrote: post #148
agnokapathetic wrote: post #138

Earlier quoted context omitted.

Yes: https://medium.com/the-downlinq/super-resolution-and-object-...

You're basically letting an AI to hallucinate details, which looks good in most cases but in edge cases may cause unintended results: https://news.ycombinator.com/item?id=24196650

Yo. That was crazy. So the whole "zoom and enhance" thing they do on TV is no longer science fiction. That meme is dead judging by what I am seeing in that thread.

Re: Why is the Gaza Strip blurry on Google Maps?

#174

Post by tpmx »

wongarsu wrote: post #150
tpmx wrote: post #16

Earlier quoted context omitted.

Maybe Starlink satellites should also feature a camera? They've already got the connectivity. You'd need a large constellation and this one seems like it will become huge.

They could do something like Sentinel's 10m/px, but looking at those images [1] I don't see the advantage of updating that more often than the once every few days we already have from Sentinel. To make near-realtime interesting you need something closer to 1m/px where you can clearly make out cars. But at that point the optics and camera take more mass than a normal star link satellite. They would become earth observ…

Yeah, I guess it would require a breakthrough in optics/lenses to become feasible. Sentinel-2 is ~1000 kg, and each Starlink satellite is approx 250 kg.

Re: Why is the Gaza Strip blurry on Google Maps?

#176

Post by wongarsu »

hhjinks wrote: post #101
JoshTriplett wrote: post #33

Earlier quoted context omitted.

In addition to cost, there are various national laws that restrict satellite imagery with resolution better than various thresholds.

How far into the atmosphere does a nation's air space stretch? Would I be breaking a country's law by picturing said country from orbit?

That's an unsettled question. I think most would agree that a nation's airspace extends at most up to the Kármán line, which is 100km above sea level (except in the US, where it's 80km or 50 mi). But there is no international treaty or anything that settles this.

In practice, as a satellite operator you are bound to the laws of the country where your company resides, the country where you launch from, the countries where your ground stations are, and any country that has political sway in any of the previous ones.

Re: Why is the Gaza Strip blurry on Google Maps?

#177

Post by tomerv »

jrochkind1 wrote: post #113
squeaky-clean wrote: post #97

Not really related to the article at hand, but I've been on a bit of a Google Maps binge the past couple weeks. I learned a few interesting facts, blurry Israel being one of them. Another strange thing I found that might not be super well known (I didn't know about it) is that all GPS data in China is offset by a nonlinear psuedo-random amount. If you turn on the satellite view in Google Maps and look at various citi…

My memory says that US government GPS at one point intentionally introduced reduction in accuracy/resolution as well, but they stopped, which was part of what led to the commercial GPS revolution (along with cheaper tech of course). Let's see... Wikipedia seems to confirm: > During the 1990s, GPS quality was degraded by the United States government in a program called "Selective Availability"; this was discontinued o…

Interesting to note that the removal of selective availability enabled the creation of Geocaching ( https://en.wikipedia.org/wiki/Geocaching#History ).

Re: Why is the Gaza Strip blurry on Google Maps?

#178

Post by dragonwriter »

manquer wrote: post #126

There is perhaps an interesting machine learning application here. There are higher resolution images available at lower frequencies and low resolution images possible with high frequency. Would it not possible to "zoom and enhance" a low resolution image to higher resolution one using historical high res data of the location and learning from object types and classification?

> Would it not possible to "zoom and enhance" a low resolution image to higher resolution one using historical high res data of the location and learning from object types and classification?

Sure. Probably provide pretty convincing high-detail images.

For the cases of most interest—i.e., when the new activity is unusual and unexpected—it will often be detailed, convincing, and completely wrong, though.

Re: Why is the Gaza Strip blurry on Google Maps?

#180

Post by acomjean »

jrochkind1 wrote: post #113
squeaky-clean wrote: post #97

Not really related to the article at hand, but I've been on a bit of a Google Maps binge the past couple weeks. I learned a few interesting facts, blurry Israel being one of them. Another strange thing I found that might not be super well known (I didn't know about it) is that all GPS data in China is offset by a nonlinear psuedo-random amount. If you turn on the satellite view in Google Maps and look at various citi…

My memory says that US government GPS at one point intentionally introduced reduction in accuracy/resolution as well, but they stopped, which was part of what led to the commercial GPS revolution (along with cheaper tech of course). Let's see... Wikipedia seems to confirm: > During the 1990s, GPS quality was degraded by the United States government in a program called "Selective Availability"; this was discontinued o…

When I was a civil engineer last century gps accuracy was an issue because people wanted to use gps for surveying. They came up with a system that would use 2 receivers and a radio between them to get much higher accuracies.

https://www.e-education.psu.edu/natureofgeoinfo/book/export/...

I think the US Government can also shut it off at a moments notice.

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