Am I right in thinking that maps bought for one Garmin can't be used with another one?
Is there any advantage to using Garmin maps compared with open source maps?
What maps do you use on your Garmin?
Thanks.
fuaran pretty much nailed it wrt Garmin maps.
I used Garmin Topo maps for a long time but found them limiting because they are only very rarely updated. Last I saw they were still selling Topo v2, which I first bought in 2006. It also isn't good at navigating along anything you can't drive a car along, so where I lived it took me on lots of roundabout routes because it didn't know about the cycle lanes and cycle lane contraflows etc. So it would route me on a fairly long diversion because it didn't know about the pedestrian/cycle underpasses and bridges over the A3, for example.
When set in cycling mode the Topo maps on my old 60CSx avoided motorways and tried to avoid busy main roads, but sometimes that had unwanted side effects when it told me to turn right across the traffic on a main road, only to run parallel to the road for half a mile and then turn right across the traffic to get back onto the main road. The road in question has a 30mph speed limit and a cycle lane.
For the last several years I used OSM maps because they update often and are free. The downsides I found with OSM maps, aside from the proliferation of uninteresting icons Ben T mentioned, was that the routing was what I might describe as "interesting". I'd prepare a route in advance and upload it as a track because telling my GPS to find a route would often result in spectacularly roundabout routes and spectacularly inappropriate routes. Set to cycling mode it knew I was allowed to use bridlepaths. One such path it routed me down was two inches of water over about four inches of wet mud, barely 12 inches wide with six foot high stinging nettles on both sides. Another path was dry but barely visible between the stinging nettles, and it had six foot high metal poles obstructing the entrance and a "No Cycling" sign on it. For local rides that's not necessarily an issue but when I was trying to plan a long route with OSM I didn't want to find myself faced with the choice between two miles of a hideously muddy bridlepath or a detour taking in the busiest roads in the areas. And of course if you put it into regular driving mode, it quite correctly reported that the best route to where I was going was to take the M3.
I haven't updated my OSM maps for a couple of years now so they may have improved substantially in that time. Complaints aside, if you're not using them for routing they're a good option to go with, and if you find a road/trail/whatever that is wrong or missing you can update the maps yourself.
