Recently at an OSM meetup with the local government in Aachen (Germany), they mentioned that some imagery they shot was deemed too invasive and only used internally. I thought that was 10cm, but now checking what is available, looks like I was wrong! Probably it was 5-7cm then? Or maybe this was rather about the imagery available from different angles, so you can see into gardens from different directions?
In iD I see that indeed the PDOK imagery is now labeled 7.5cm, but checking that against the Belgian and German 10cm:
That is indeed awful, you're right. I remember that satellietdataportaal.nl or something like that allowed access to uncompressed files, maybe they're better. I'll see if I can find my old credentials and compare.
But yeah, compared to those 10 cm images, that can't be effective 7.5 cm/px.
Related: Apple Maps uses some data source that is ridiculously high res for my street. They've updated the image now sadly, but for a while I saw a gangly brown haired silhouette chasing two blonde haired kids across the street. I was super sure that was me and my kids; slanted shadows gave the right relative sizes, too. Cool and creepy at the same time.
For the Dutch railway network, ProRail has commissioned a set of aerial images shot from a helicopter at a height of roughly 190 m, which is ridiculously high-res and available for viewing here: https://twiav.nl/nl/luchtfoto_prorail.php
You can clearly make out individual paving stones or even the catenary wire, so the resolution must be somewhere in the 1 or 2 cm range.
