Tried this (post 16/19) as soon as I learned of it, zoomed in on a part of Antwerpen in Belgium, specifically the intersection of the Ferdinand Coosemansstraat with the Walemstraat and the adjacent Wasstraat ; also used the bpost.be posting box finder to check for any nearby posting boxes.
1/ in ID, the ‘key’ and ‘img_keys’ values are rather long sequences, and can’t be copied/pasted - therefore no apparent way to view the photo on which M’y detected the posting box;
2/ dots from the mailbox file do not coincide with dots on Mapillary when zoomed in - can’t view the specific pic on which the mailbox was detected that way, either;
3/ bpost.be has a posting box finder, see https://www.bpost.be/site/nl/rode-brievenbussen , searched for Walemstraat 6 postcode 2600, which is where there are four clustered dots in your mailbox json file - returned as nearest posting box Belpairestraat 85, which by the way was not detected by Mapillary.
4/ jumped on the bicycle to view the spots, uploading the sequence as I type this, essentially : there are no posting boxes in the Ferdinand Cooremansstraat anywhere near where M 'y detected them and placed four dots, and there isn’t a posting box in the adjacent Wasstraat near number 11, where there is one detection;
5/ there is a well hidden posting box in the Belpairestraat, outside number 85, as predicted by the bpost.be posting box finder.
Points for improvement :
a/ properly define the words posting box (where stamped addressed mail is placed by the sender for collection by the postal service) and letter box (the destination of the letter where the postal service worker will deposit the item for the recipient to pick up ;
non-native english speakers looking for a word tend to turn to google.com which lists letter box as “a box attached to an outside wall, or a slot in the door of a building, into which mail is delivered.”;
please avoid ‘mailbox’ : google.com gives two (North American) meanings, which are ambiguous in that they can apply to either “a box into which mail is delivered, especially one mounted on a post at the entrance to a person’s property.” or “a public box with a slot into which mail is placed for collection by the post office; a postbox.”.
b/ there needs to be a workable link for the mapper to view the photo on which the posting box was detected, which will help in placing the feature in the best possible spot.
c/ in the interim, while s/o works on point b/ above, could the dots in the json-file please coincide more exactly with the track when zoomed in?
With high regards, and do keep up the good work,