Recommended alternative maps for Garmins

[Wojtas81]

Here is my list of OpenStreetMap based maps for Garmin handhelds and watches:

For hiking: V0174, VasaM, OpenTopoMap, Freizeitkarte, Frikart, UserBeam, MapRando
For hiking (paid): TalkyToaster
For cycling: VeloMap, OpenMTB, OpenFietsMap
For cars: OpenMapChest, AlternativasLibres
Other/general: BBBike

[GPSrChive]

There are a few more options listed at GPSrChive > Garmin > How To... > Maps as well.

I personally load the GMapTool maps on all of my devices. If you find yourself in one of the covered areas, give them a try!

[Ziginox]

Seconding Andrzej Popowski's excellent maps over at gmaptool, they're the best I've used so far. They make a USA map with 'everything including the kitchen sink'. OSM data, USGS woodland data, DEM, elevation and depth contour lines, as well as being routable. Supposedly also has address search, but I've been struggling to make it work. They also have a

I wanted to add on that maps exported from OpenFietsMap do not contain a digital elevation model. Probably not an issue if your unit comes with a DEM basemap.

Also, VeloMap is only free in certain regions, other require a membership.

Another option, which I have downloaded but yet to try, is OpenMapChest. Direct downloads require payment, or are free using a torrent client.

[Wojtas81]

Probably not an issue if your unit comes with a DEM basemap.

BaseMap (ie. gmapbmap.img file) is very low detailed. It is only used when you zoom out above certain level.
Without BaseMap normal maps will be used (above some level of zoom out) which will be painfully slow, because they are too detailed.
So BaseMap is de facto necessary for your device to function 100% correctly.

Digital Elevation Model is contained in gmapdem.img file which contains detailed elevations for entire region (eg. entire Europe).
Some third-party maps also contain their own DEM data, so separate gmapdem.img file (that comes with original TopoActive maps) is not needed.

[javawa]

Some basemaps do contain DEM data... These files are very small though, the DEM resolution is so low that it is hardly useable.
The DEM map of Europe (included in TopoActive EU) is 1.3 GB. If you need really detailed DEM: just for my country (The Netherlands) it's 7 GB, it has a resolution of 50 cm.
The basemap with DEM is about 50 MB for the whole earth; the DEM part of that file is just 30 MB.