I think these maps are viewable down to the 0.8mile resolution of a Garmin handheld, any closer than 0.8mile, e.g. 0.5miles, and the mapping reverts to the road map.
Raster maps have limited zoom in/out range when they remain readable.
Thanks for the responses. Definitely some unexpected behaviour going on as sometimes the 0.8mile and out raster roadmap view works and on other occasions it does not. With the earlier v3 1-50k map loaded in place of the v4, I consistently get the roadmap view at 0.8mile and outwards.
When I have more time I'll experiment a bit more to see if it is some kind of firmware bug or due to the combination of other maps loaded.
I just loaded the UK 50k v4 maps on my 62s and Oregon 600, disabled all other maps and the results are identical on both units: when zooming out I get the European Basemap at zoomlevel 30Km, all levels below show the rastermap. The map contains several layers of rastermaps showing more detail when zooming in.
I also checked it with v3 and I am getting the same result. I like v3 better however because it's jpg-compression is lower, v4 looks really ugly when zooming in.
Did you disable all other maps in your GPS (internal and SD)?
Nüvi 2595 / 60CSx / 62s / Oregon 600
Appreciate you taking the time to help investigate. All other maps are disabled and still get the issue. When I get a moment I'll try a different SD card in case there's a problem with that.
Will report back.
Confirmed that this behaviour was entirely my fault, inadvertently had one or two other maps enabled that clashed at the zoom level.
Tried the maps on my Oregon 650 and I got a message that the ordnance survey maps are a trial and will be deleted in April. It only appered the first time . Any help appreciated.