Originally Posted by velonomad
Thanks for the feedback, I didn't realize the GPS base maps could be both land and marine. that makes it even more useful since I mess about in boats also.
Am I correct in assuming that the mapping software is proprietary to each manufacturer? for instance my TopoUSA V5 will not work in a Garmin, will it?
Actually it is not the basemap. It is some of the functionality. The marine GPS devices have waypoint symbols for marine use (buoys, lights etc.) where the other GPS devices have those symbols reserved for something else.
All the Garmin GPS devices have the same basemap in the US. Except for major roads the map is pretty much worthless. You will need to buy a product like City Select to get any detail. I also own Blue Chart for the Chesapeake Bay. I use this on my 176. It is not as portable as the 76C but has a larger screen. The marine charts can be very expensive. The Chesapeake Bay cost over $100 alone.
Yes maps are proprietary by GPS manufacturer. With possible exception of the IQue (which turns a palm computer into a GPS). I believe this model will use
ENC charts . ENC charts are available from the government for free but are for marine use only. The government does provide free digital road maps but they can't directly be used by any GPS including the IQue.
There is 3rd party software that allows you to make your own maps but this can be very tedious and those maps are not supported by Garmin. In theory, you could use this software to convert the free government road maps. You "might" also be able to convert your topo map with this software but it would not be easy.
Garmin and other manufacturers use these free maps and charts to create their own maps and charts to sell to you.