There is an significant increase in OSM map data which is great. But, with that increase in data comes a price. My GPS can only load 4000 tiles and/or 4GB of map data. If I want all of the US or EU on my GPS there is no way with the current mkgmap. Is anyone working on a compatible Garmin NT compiler?
Officially, Garmin supports free(osm) maps. At least they have a free-maps board in their
official forums. But anyway, when they would open the file formats, other commercial
map makers would be competitional to garmin own maps. So, I think they will keep them closed.
“Garmin Custom Maps” are georeferenced raster maps. That’s the main direction of that forum. Occasionally vector map questions get posted there, but that’s not the main focus.
That said, some of the developers present on the BaseCamp forum have been surprisingly helpful.
Let’s come back to the 4GB limit. Presently, map makers try to put “all” available data into their maps, and thus maps in well mapped regions become very big. But do you really need all that information in your map? When you need a map for navigation in your car, that will work as well without showing buildings. You can also omit agricultural tracks and hiking trails. Some people also like to hide industrial areas, forests, etc. Several “points of interest” can also be omitted. “Selection” instead of “inclusion” is the way to go.