3 ms·

EDIT: realising adding a comment here contributes another datapoint.

by demarq 4y ago

bubblic 4y ago
the algorithm works this way: The geolocation acquired by the webpage is in the form of latitude and longitude. Let's say it is lat: 10.123456, long: 30.123456 I want to approximate it to 3 mile accuracy (diagonal of a box, so in one dimension, would be sqrt(3^2 /2) = 2.12 mile in lat or long). 3 mile, in geographical coordinate would be equivalent to : 3 mile / 3960 mile (Earth radius) * 180 deg / pi rad = 0.0434 degree. I divide each dimension by 0.0434, and round it to a whole number (essentially, mod 0.0434). Then, I multiply that number by 0.0434 and save that as the location. This means that a user's location can lie anywhere inside a box with 3 mile diagonal length at that geolocation. If you see inconsistency in my logic, please let me know.
- JonChesterfield 4y ago
  That would leak if there are multiple data points. In the extreme case, two points just either side of the 3 mile circle resolution would locate precisely (where the two circles touch). Given N points within M meters or so, which is roughly what you get for multiple measurements of "home" with an error on the measurement, I think you could have a reasonable stab at deriving the location from an estimate of the error on the geolocation plus which circles they fell into. All in same circle makes near centre more likely than near edge. edit: daily check in, so all the above needs is a tendency to check in from roughly the same location each day.
metadat 4y ago
> Pinpoints down to the nearest street This information isn't personally identifiable by itself. Even combined with your original HN comment, the information leakage cross section and associated risk is minutely small. I understand the concern about your privacy, but in practical terms what outcome are you afraid of in this instance? Getting less lonely inherently requires some degree of trust in and vulnerability to other human beings. It's tragically sad when privacy fears prevent someone from living a colorful, stimulating, and deeply fulfilling life. In case you're open to unsolicited advice: Develop the skill of Discernment. When the "privacy threat" part of your brain activates, take a moment to analyze the degree of the threat and intentionally choose your response accordingly.

EDIT: realising adding a comment here contributes another datapoint.

by demarq 4y ago

EDIT: realising adding a comment here contributes another datapoint.

the algorithm works this way: The geolocation acquired by the webpage is in the form of latitude and longitude. Let's say it is lat: 10.123456, long: 30.123456 I want to approximate it to 3 mile accuracy (diagonal of a box, so in one dimension, would be sqrt(3^2 /2) = 2.12 mile in lat or long). 3 mile, in geographical coordinate would be equivalent to : 3 mile / 3960 mile (Earth radius) * 180 deg / pi rad = 0.0434 degree. I divide each dimension by 0.0434, and round it to a whole number (essentially, mod 0.0434). Then, I multiply that number by 0.0434 and save that as the location. This means that a user's location can lie anywhere inside a box with 3 mile diagonal length at that geolocation. If you see inconsistency in my logic, please let me know.

JonChesterfield 4y ago
That would leak if there are multiple data points. In the extreme case, two points just either side of the 3 mile circle resolution would locate precisely (where the two circles touch). Given N points within M meters or so, which is roughly what you get for multiple measurements of "home" with an error on the measurement, I think you could have a reasonable stab at deriving the location from an estimate of the error on the geolocation plus which circles they fell into. All in same circle makes near centre more likely than near edge. edit: daily check in, so all the above needs is a tendency to check in from roughly the same location each day.

metadat 4y ago

> Pinpoints down to the nearest street This information isn't personally identifiable by itself. Even combined with your original HN comment, the information leakage cross section and associated risk is minutely small. I understand the concern about your privacy, but in practical terms what outcome are you afraid of in this instance? Getting less lonely inherently requires some degree of trust in and vulnerability to other human beings. It's tragically sad when privacy fears prevent someone from living a colorful, stimulating, and deeply fulfilling life. In case you're open to unsolicited advice: Develop the skill of Discernment. When the "privacy threat" part of your brain activates, take a moment to analyze the degree of the threat and intentionally choose your response accordingly.