Hi,
while starting with a .gmap folder one can produce easily an IMG with a subset of the initial map tiles, sometimes the .gmap is not available, just an .IMG, such as it happens with OSM derived maps.

I do it using the following steps:
- create an instalable set using a reg file - for that I use GMaptool + mkgmap
- install it in Basecamp using the created reg file
- open Basecamp an "install" the map in a (virtual) receiver; after one needs to make it visible in Basecamp (for example with javava device manager)

Not so cumbersome, only the creation of the installable in basecamp in a bit awkward, as there is a stone in the road... the map in basecamp shows blank from far away zoom until very close (usually in the range of 50kms), no information, just empty layers, showing the rectangles that correspond to the map tiles. So one has to guess which ones to select and/or zoom in/out to select the interesting tiles. Error prone, sometimes too many selected sometimes too few.

I wonder how this could be made easier. Wether making the top layers transparent, or adding the contents of the lower layers to the top layers, or replacing the top layers with the contents of gmapbmap.img , or finding a way to show in basecamp at the same time gmapbmap.img and the map I am working with to retain some of its tiles.

I have asked in a number of places but it looks either there is no solution or the knowledge has been lost or is well hidden... Perhaps GPSPower.net is the only right one...

So, anyone can help me on this? (either on the forum or via PM...)

TIA