I tried this and swapped the North American database for a Europe database, then did it again for Africa. Here's what I found: The Waterways & Lights CD allows you to install a special program which lets you update the internal city/marine database in a GPS48 connected to your PC. I have the new Waterways and Lights CD and a new 48 with the latest firmware so I checked it out myself.
This is something new for Garmin and leads me to suspect that perhaps we'll be able to do this with the city databases in the 12XL, 12CX or II+ in future if Garmin added a similiar program to the World Map or some future CD. I checked this by using the find city function and looking at the lists, as well as by zooming and panning around the screen a bit. The cities/towns get swapped as well, not just the navaids. always counting) Added Protocol Capability Protocol Control Added PVT data on/off commands Added drawing of accuracy circle around current position on map Added nine waypoint symbols Added capability to change the waypoint auto-naming number.
to only include map accuracy when land data is displayed on the map Changed time restriction on Trac Back operation to allow processing of more complex track logs Changed Trip Computer distance displays to show least significant digits after display width is exceeded Added on/off switch for display of accuracy circle on map Added ability to restore default backlight and contrast settings Corrected map selection and nearest determination of more than nine user waypoints Corrected ENTER key handling on waypoint list page when no waypoints exist Corrected waypoint name abbreviations that include special characters Changed the method of deleting waypoints by groups (either by symbol or all waypoints) such that non-route waypoints are deleted first, and then the user is prompted before waypoints used in routes are deleted Changed the backlight and contrast adjustment interface Changed the backlight timeout to not turn off when externally powered Changed the default timestamp on points in stored track logs Changed the waypoint name editing such that finding duplicate names does not undo the editing changes Changed perspective highway page to display the comment of the next navigation waypoint if its display options are set to "Symbol & Comment" Changed route planning to use planned departure date when no Estimated Date of Arrival is available Changed copyright year to 1997-1998 & rearranged company name for display Updated magnetic variation values (for year 2002) Added Power Saver mode feature for extending battery life Added timed automatic shutdown after external power loss Added trip timer mode selection (counting only while moving vs. Correct the display of the POI lists when changing from landscape to portrait orientation.