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I wonder how hard it would be to scan ingested maps for interesting submerged structures, and also roughly how many cars would turn up if it's feasible. I'd gue
by scarmig 7y ago
I wonder how hard it would be to scan ingested maps for interesting submerged structures, and also roughly how many cars would turn up if it's feasible. I'd guess... O(100)?
- castis 7y agoId be relatively surprised that this isn't already a thing.
- TravHatesMe 7y agoInteresting thought but uneducated guess. I bet IR scans could help, similar to how they are discovering ancient cities buried deep in the jungle.
- themodelplumber 7y agoSpace-based radar is also available which provides views of metal content as an intelligence product. Brighter parts of the image = more metal. I'm not sure if it's commercially available but it would sure help to find cars in shallow water...
- 7952 7y agoThere is a lot of other metal in shallow water though. Just think about rubbish, buoys, marker posts for utilities, boats, sewer outfalls, gratings etc.
- deleted 7y ago[deleted]
- pbhjpbhj 7y agoPresumably Google, or their contractee, are scanning with other frequency ranges (IR, UV) when they do visual photography for Google Maps. So any companies make this kind of imagery data available free; I'd be interested to see some.
- 7952 7y agoWorldview 2 has a band that is specifically intended for shallow water.
- TravHatesMe 7y agoI meant uneducated in reference to his guess of O(100). That makes no sense.
- cydonian_monk 7y agoI can't find a link to the story at the moment (I'm on mobile), but I read recently they've started doing just that - doing image analyses on aerial/sat map data - to find cars and other things submerged in the Bayous here in Houston. Previously [1] they used more on-site resources, such as sonar, drones, and people in kayaks; etc. 1: https://www.houstonchronicle.com/local/gray-matters/article/127-cars-in-the-bayous-6573111.php https://www.houstonchronicle.com/local/gray-matters/article/...
- Nicholas_C 7y agoI found a skateboard in a smaller bayou this past weekend in fairly good condition. I can’t imagine what else is down there. There is also a very surprising amount of fish in the bayous, including loads of plecos (aquarium sucker fish).
- Zhenya 7y agoYou might enjoy magnet fishing! https://en.m.wikipedia.org/wiki/Magnet_fishing https://en.m.wikipedia.org/wiki/Magnet_fishing
- outworlder 7y agoalso r/magnetfishing
- Nicholas_C 7y agoNever heard of that! I can’t imagine how many weapons one would find at the bottom of the Houston bayous.
- shpx 7y agoI wonder if there's anyone scanning satellite imagery for the word "HELP", or if we should agree on some other symbol people could use to ask for help that would be easier to discover with computer vision and wouldn't be English-specific. How large should you make the letters? Satellite resolutions range from 2m for Planet Labs, 50cm for Geoeye to ~10cm for that spy satellite Trump leaked recently. The MNIST dataset of hand written digits uses 28*28 pixels, but you can get away with less. Maybe 50 meter by 50 meter letters? If you know binary you could also include extra information by using rows of 5 squares ~1m in diameter.
- hinkley 7y agoHow about "bigger than a sedan at the bottom of a pond"?
- shpx 7y agoGoogle Maps uses aerial imagery (photos taken from planes)[0] because it's higher resolution, and I bet that's what you're seeing here. They don't fly those planes often and they don't fly them over random uninhabited islands, whereas there's a company that takes satellite images of all the land on the planet daily. [0] https://support.google.com/earth/answer/6327779?hl=en https://support.google.com/earth/answer/6327779?hl=en
- journalctl 7y agoI can’t imagine getting the entire world to learn a new symbol for “help” on the off chance someone needs to signal to passing satellites. Also, I believe SOS is fairly well-known.
- ada1981 7y agoHow frequently do we refresh our coverage of imagery of planet earth? Some sort of universal symbol could be great. Especially if you knew that within X days there was a strong chance it would be spotted and rescue folks alerted.
- shpx 7y ago
- quickthrower2 7y agoHate to be that nitpicky guy but O(100) isn't a thing. You'd write O(1) or O(N), O(N^2) etc.
- corndoge 7y agoWhile not technically correct the meaning is clear enough and commonly used as shorthand for "on the order of"
- nielsole 7y agoI thought O(1) = O(100) so it would still technically be correct, no?
- quickthrower2 7y agoEdit: O(1) technically is O(100) but that's probably not what they meant.
- sergioj97 7y agoIt would be technically correct if what he meant was that the problem would be solved in constant time. I bet it wasn't.
- hyperbovine 7y agoThat is the sort of pedantry up with which I will not put. From the definition of big-oh, the choice of the number one is completely arbitrary.
- cat199 7y ago> From the definition of big-oh, the choice of the number one is completely arbitrary. is it? not up on the formal theory, but: O(n) -> on the order of n x 1 time intervals of processing O(n)^2 -> on the order of n x n time intervals of processing etc. so if there is a single fixed interval, N is irrelevant, leaving you with 1, denoting the single fixed interval