Imagine you are a popular content creator on PixelFed, many followers, but many stalkers also. You don’t want people to know where you live. One day you post a picture of the sun out of your window. Exact time is attached in metadata. Assuming GPS metadata is stripped, can someone, using inclination of the sun to the horizon, Nautical Almanac and some math calculate your latitude and/or longitude, and to what precision? Assuming also meteorological data archives on cloudiness, etc.
Maybe if they are determined enough.
It’s a perfect example of the reason why I post pics of places that I’m not really at and that I’ve never personally taken.
I have a Lemmy stalker, and I love randomly planting fake personal asides in my texts so he has no idea where I really am. Like this morning when I took a stroll along the riverfront and posted some pics of my nice peaceful walk. The light rain was so pretty, and we really needed it in this area after the hot weather. The mountains are so pretty here in this light!
He always falls for it and tries to say he knows where I am, while dropping hints about me and saying I need to watch my back. Dude isn’t even right about the country I’m in, my gender, or what nationality I am. I have never given an honest clue about myself on Lemmy since I’ve been on the platform.
Every single thing I have ever said about myself to anyone on here under any username, is completely false. :)
Winding him up with so many false clues is kinda fun for me. It’s like an enjoyable psyops hobby. He falls for it every single time.
Then he’ll get mad, ragequit Lemmy, and say he’s done with the platform because he thinks I’ve ruined Lemmy. Then comes back on and resumes stalking me few days later, calling me the same made-up nickname he created for me (based on a Reddit post that also wasn’t me) while swearing I am a bunch of different posters that I’m not.
No idea why he thinks I am so many different people. Other than he tries to read all my fake clues which he then associates with other posters I guess? He thinks most of Lemmy is me now. Ya really can’t use logic w guys who get obsessed like that.
So OP, never post anything that is real on here. Way too many unhinged people.
Check out the downvote I got for this comment. He showed up right on schedule! His voting history on lemvotes: Total post upvotes: 1. Total post downvotes: 1644. lolololol
Latitude can theoretically determined by the data in your picture (although a picture of the clear night sky would be better). Longitude is much harder, because you can’t really tell how far east and west you are based on the angle of the sun alone. This was a historic problem, especially when mankind started traveling across oceans.
The problem can be solved by knowing your time relative to some reference point. This is how Greenwich Observatory became so important to timekeeping: to determine longitude, ships had to carry a good clock that showed them what time it was at Greenwich, and the difference in time between when the sun was directly overhead on the ship and noon at Greenwich told them their longitude.
So, the main piece of information that gives away your longitude is actually the timestamp, assuming it is either stored as UTC or as local time with a UTC offset, because then you have an idea where the sun is and can relate it to noon UTC. (A date and UTC offset also indirectly discloses what time zone you are in…)
There’s literally a hobby where people find locations based on pictures stripped of all metadata with very little visual info.
If someone really wants to dox you, the only way to stop that vector is to never post pictures that show outside where you are
You can be geolocated from purely interior details too. Outlet types and other details can be combined to get pretty close.
There was once a Japanese celebrity who’s stalker was able to find out her location by a street sign that was reflected in her eye. You don’t need an astrolabe to be a creep.
They can get a good idea, but more likely they will use other things in the background like trees and buildings.
Buildings would be easier. I triangulated a dude’s position once in istanbul from a photo of his balcony
I’ll just add that to the list of why i never take pictures and much less upload the rare few i have been forced to take.
At any given moment there’s a full circle of points on the surface of the earth at which the sun has the same given zenith angle. So without any other information, the best you could do is narrow it down to some point on such a circle (and that’s provided you can figure out the difference between the apparent and true horizon, the effects of potential lens distortion, etc.).
The usual issues of longitude and latitude don’t come into play, since those were historically based on a combination of not knowing the precise time, but being able to establish exact latitude based on observing the stars (instead of the sun). In this case you do know the exact time, but you have no independent way to determine latitude.
But then come in the geoguessers and based on other clues will figure out the exact location, probably within few minutes.
A correct guess often isn’t based on a single clue, but on using multiple clues to narrow the possibilities down in different ways. So every potential clue matters and should be considered, instead of assuming it’s irrelevant because there are other clues present as well.
It all depends on the land in the picture.
If there were only sky and sun, nobody knows direction or height or place.
https://colab.research.google.com/github/GalenReich/ShadowFinder/blob/main/ShadowFinderColab.ipynb
So pretty accurately, if somebody wants they can find your house.
In this example, where only the sun is pictured in relation to an indoor window, and no other information is present, it would be very difficult to make any kind of meaningful calculation. You could probably identify some information about the camera based on the proportion of the disk of the sun, but unless you had some additional information, such as the precise dimensions/compass direction of the window, or the location of the horizon, It would be impossible to make a calculation of this type. There just isn’t enough information.
