3 ms·

Interesting. Though I did a web app for a single city event with 100 locations. I did the "distance to my current location" calculation without taking the cu

Interesting. Though I did a web app for a single city event with 100 locations. I did the "distance to my current location" calculation without taking the curve into account, and it worked fine for that small area. Also determined that 0,0 is located on the equator off africa south of england (kinda obvious in hindsite).. Which means you probably should make sure all your locations are geotagged before including on a map...

yunruse 6y ago
This is a property of the small angle law; the great circle is only appreciably different to a “straight” Mercator path on the scale of a flight spanning a European country or two.
jimmaswell 6y ago
https://en.wikipedia.org/wiki/Null_Island https://en.wikipedia.org/wiki/Null_Island For some reason I remembered this point being somebody's house that got a lot of unwanted visitors due to the coincidence. Was there something similar like that?
- EE84M3i 6y ago
  You're probably thinking about https://www.washingtonpost.com/news/morning-mix/wp/2016/08/10/lawsuit-how-a-quiet-kansas-home-wound-up-with-600-million-ip-addresses-and-a-world-of-trouble/ https://www.washingtonpost.com/news/morning-mix/wp/2016/08/1... which is about the maxmind geoip database using a specific coordinate for when they don't know anything more accurate than "United States"
  - chipsa 6y ago
    This is why you need both a location and a certainty when giving back geotagged info, and when you get it, you don't display a point, you display an appropriately sized circle. So you get something that actually resolves to "US", you draw a circle centered on the US, covering most of the US, instead of a point marker in the middle of the US.
- thristian 6y ago
  Often, when a database entry is geotagged with a country, province, or city, trying to plot that entry on a map will result in a marker being drawn at the exact geometric centre of the region, implying more precision than actually exists. When the database entry represents something important to people, like stolen property or a missing person, and something happens to be at the place the map marker lands, desperate people can do desperate things.

yunruse 6y ago

This is a property of the small angle law; the great circle is only appreciably different to a “straight” Mercator path on the scale of a flight spanning a European country or two.

jimmaswell 6y ago

https://en.wikipedia.org/wiki/Null_Island https://en.wikipedia.org/wiki/Null_Island For some reason I remembered this point being somebody's house that got a lot of unwanted visitors due to the coincidence. Was there something similar like that?

EE84M3i 6y ago
You're probably thinking about https://www.washingtonpost.com/news/morning-mix/wp/2016/08/10/lawsuit-how-a-quiet-kansas-home-wound-up-with-600-million-ip-addresses-and-a-world-of-trouble/ https://www.washingtonpost.com/news/morning-mix/wp/2016/08/1... which is about the maxmind geoip database using a specific coordinate for when they don't know anything more accurate than "United States"
- chipsa 6y ago
  This is why you need both a location and a certainty when giving back geotagged info, and when you get it, you don't display a point, you display an appropriately sized circle. So you get something that actually resolves to "US", you draw a circle centered on the US, covering most of the US, instead of a point marker in the middle of the US.
thristian 6y ago
Often, when a database entry is geotagged with a country, province, or city, trying to plot that entry on a map will result in a marker being drawn at the exact geometric centre of the region, implying more precision than actually exists. When the database entry represents something important to people, like stolen property or a missing person, and something happens to be at the place the map marker lands, desperate people can do desperate things.