Garmin City Navigator North America On Minnesota State Park Roads


I spent much of my afternoon yesterday in Banning State Park and, after dinner with my wife and mother in law, Saint Croix State Park in east central Minnesota. I was using my MIL's vehicle, which has a Garmin Nuvi 3597 and City Navigator 2020.10 installed on it. I was slightly surprised to find out what state park roads that did not show up on the device while I was navigating.

As a side note, these were primarily gravel roads. I think all of the blacktopped roads did show up. Also, all of these gravel roads are well established and have been in existence for many years. I know, because I have driven on them many years ago.

Anyway, does anybody here happen to know at what point a road is recognized and added to the software? I know some trails actually show up, but some park roads/forest roads don't show up!

Also, I checked Google Maps for that area and did some comparisons. I also brought up Map Source on my laptop/desktop. It looks like some roads that are on Google Maps and Garmin Map Source don't show up on the Garmin Nuvi 3597. I am just wondering if anybody here has noticed anything similar?,-92.7051107,12.87z/data=!4m5!3m4!1s0x52b20c19296c0889:0xbafab3f15aaa5e37!8m2!3d46.0119822!4d-92.6176169