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Why is the Gaza Strip blurry on Google Maps?

bbc.com

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

#131

Post by thaumasiotes »

qart wrote: post #105
areoform wrote: post #85

Earlier quoted context omitted.

It's one of the most heavily imaged areas in the world - on the ground, as it's an active conflict zone. In space, satellites will pass over the region every X hours no matter what. Planet's satellites have a fresh, high resolution map of the Earth ~3.5 hours. Google had, at the very least, 7 satellites imaging the Earth in 2017, https://en.wikipedia.org/wiki/SkySat . The question isn't whether the data exists. It do…

> The question isn't whether the data exists. It does. What is your basis for this claim? However many satellites Google has, why are the regions I named blurry too? Lebanon isn't that far away from Gaza. Cars at Chekka looked like specks. Across the sea, in Cypress, I could make out the front and rear windows of cars.

>> The question isn't whether the data exists. It does.

> What is your basis for this claim?

This is a really surreal response, given the part of that same comment that you seem to have forgotten to read:

>> In space, satellites will pass over the region every X hours no matter what. Planet's satellite have a fresh, high resolution map of the Earth ~3.5 hours. Google had, at the very least, 13 satellites imaging the Earth in 2017, https://en.wikipedia.org/wiki/SkySat . It is unclear, to me, how many space assets they do have, but I'm guessing they image the entire globe every week, at the very least.

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

#132

Post by Rebelgecko »

throwaway894345 wrote: post #119
caymanjim wrote: post #34

Earlier quoted context omitted.

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.…

What limits the field of view of these LEO satellites? Why can we not have high resolution images of wider swaths? Is it something like the number of "receptors" on an imaging cell, or would wider angle lenses significantly distort the imagery?

The curvature of the earth is gonna be a limiting factor for satellites in LEO. IIRC at 500 miles up you can only see (roughly) 1500 miles away. And realistically your range will be less than that because something that far away will be at a very oblique angle, which means more atmosphere in the way and more distortion

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

#133

Post by [deleted] »

adolph wrote: post #114
panarky wrote: post #67

Earlier quoted context omitted.

Starlink is seeking approval for tens of thousands of low-earth-orbit satellites. Each one will have high-bandwidth network connections. It doesn't seem intractable to put cameras on each one and stitch their feeds together for imagery that's maximum 30 minutes old for any arbitrary point on the globe. And the market for near-real-time imagery might be even larger than the market for internet connectivity.

The next generation of LEO ground imaging satellites will be significantly larger than Starlink units. Now, with the resolution relaxation from the United States Government that went into effect on February 21, 2015, you have access to an even clearer view of the ground with 30-centimeter resolution commercial satellite imagery. https://spacenews.com/a-detailed-view-of-the-ground-with-30-... WorldView-3 is the indust…

[deleted]

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

#134

Post by sequoia »

Tangentially related but where does this come from and why is it so widely repeated (as in this article):

> ...Gaza, one of the most densely populated places in the world

I've seen this claim (both in the "one of the most..." and "the #1 most..." forms) many times and I don't know where it comes from. What am I missing?

Here[0] wikipedia says Gaza Strip has ~5,046/sqkm. I thought maybe Gaza City was meant, it's density is 13,000/sqkm[1]. Neither of these come close to ranking on wikipedias list of cities by population density[2], and I haven't been able to find any "most populated places" lists that list anything below 15,000 people per square kilometer, which Gaza city is well below.

Is the BBC just plain wrong here or am I missing something? I hope it's me because if it's the former, that says something really bad about their fact checking and would suggest that BBC is not a reliable/trustworthy source, at least on this topic.

    0: https://en.wikipedia.org/wiki/Gaza_Strip
    1: https://en.wikipedia.org/wiki/Gaza_City
    2: https://en.wikipedia.org/wiki/List_of_cities_proper_by_population_density

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

#137

Post by qart »

thaumasiotes wrote: post #131
qart wrote: post #105

Earlier quoted context omitted.

> The question isn't whether the data exists. It does. What is your basis for this claim? However many satellites Google has, why are the regions I named blurry too? Lebanon isn't that far away from Gaza. Cars at Chekka looked like specks. Across the sea, in Cypress, I could make out the front and rear windows of cars.

>> The question isn't whether the data exists. It does. > What is your basis for this claim? This is a really surreal response, given the part of that same comment that you seem to have forgotten to read: >> In space, satellites will pass over the region every X hours no matter what. Planet's satellite have a fresh, high resolution map of the Earth ~3.5 hours. Google had, at the very least, 13 satellites imaging the…

I asked another question too. Why not answer that, then we can discuss surrealness. Ironically, my second question was right after my first question.

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

#138

Post by agnokapathetic »

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?

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

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

#139

Post by johnmcelhone »

Macuyiko wrote: post #89
caymanjim wrote: post #34

Earlier quoted context omitted.

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.…

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.

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

#140

Post by iamacyborg »

redfern314 wrote: post #118
panarky wrote: post #67

Earlier quoted context omitted.

Starlink is seeking approval for tens of thousands of low-earth-orbit satellites. Each one will have high-bandwidth network connections. It doesn't seem intractable to put cameras on each one and stitch their feeds together for imagery that's maximum 30 minutes old for any arbitrary point on the globe. And the market for near-real-time imagery might be even larger than the market for internet connectivity.

This is more or less the business model of Planet [0], which is imaging the whole Earth every day with around 200 satellites. (No affiliation, but I previously worked for a different smallsat company.) It would be possible to get a higher visitation than that with more satellites, but it may not be cost-effective (e.g. someone might be willing to pay $X for a subscription to daily images, but not $(48*X) for half-hou…

I can’t help but be excited by the possibilities of tech like Planet, so many interesting applications for their data.
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