[atlas] Probe location obfuscation

Hi,

On 2021-03-25 13:00, Ponikierski, Grzegorz via ripe-atlas wrote:
> I would add to it additional problem that some hosts obfuscate probe 
> location even more. For example you can find probes which in reality are 
> located in US but are marked as CN or probes which are in reality in 
> Wisconsin but are marked in California. Of course these are extreme 
> cases. I guess most hosts just put a pin with probe location just 
> somewhere around where it's locate as long it's in the same city. I 
> don't remember, as a host of 3 probes, to get any precise 
> recommendations how to mark probe location. Personally I just put a pin 
> in city district where probe is locate.

We don't have strict rules about precisely how the hosts should 
geolocate their probes -- and could not enforce those even if we had 
them. Instead we recommend doing this "roughly correct", which for some 
hosts means city / neighbourhood is good enough, for some others it's 
the exact spot of the utility box at home :-)

> Can anyone confirm the geo-location obfuscation of probes as being up to 
> 1km as per 
> https://atlas.ripe.net/about/faq/#are-the-locations-of-probes-made-public <https://urldefense.com/v3/__https:/atlas.ripe.net/about/faq/*are-the-locations-of-probes-made-public__;Iw!!GjvTz_vk!EWq0OCOmS-1Af9zWmGzygQZxC02O19msR11hqwe7X3bHqvxoqX8Tt17N3fDKNB4$>
> 
> I am a Phd student carrying out research on the RIPE atlas platform and 
> an early result seems to indicate 1 probe has an obfuscation of 10km 
> distance but this may be an anomaly or perhaps something not taken into 
> account as yet.

We have a very simple algorithm that does the obfuscation consistently 
with a certain maximum distance added, which may not be precisely 1km. 
We can talk offline about the details if you're really interested in the 
precise method.

Cheers,
Robert