How do multiple .typ files interact on GPS

[nm_map_user]

Let's say I make a new mapset with a custom .typ file. This mapset is transparent and is intended to be used as an overlay on standard garmin maps.  From what I'm reading, the gmapsupp.img file has the .typ file merged into the file. Can it have more than one? If gmapsupp.img is produced from multiple mapsets, are the .typ files merged somehow? What happens if there are collisions in codes?

[eaparks]

There's no problem using multiple custom .typ files for different mapsets.  You assign a FID number to your custom .typ file when you create it and this FID number must be identical to the FID number you use in MapSetToolKit.  The FID numbers being the same is what associates the custom .typ file with the compiled finished map.  Different MapSets must have different FID numbers.

You can also use 1 custom .typ file for multiple custom maps as long as you compile each of these custom maps into 1 mapset.  Your just putting different custom maps (as individual map tiles) in 1 mapset.

I have more than 30 custom ATV trail  maps plus about 8 more custom river maps, thus exceeding the number of custom Vector maps that my Oregon 450 will recognize, so for my Arkansas ATV Trail maps I create 1 Mapset called "AR ATV Trails" that has 8 different custom ATV trail maps for different riding areas... 1 Mapset, 1 custom .typ file, and 8 custom maps =  map tiles.  I have to use the same scenario for TN, KY, UT, and CO.

[nm_map_user]

The FID numbers being the same is what associates the custom .typ file with the compiled finished map.  Different MapSets must have different FID numbers.

Is there a master list of Family IDs to prevent collisions? A lot of my interest is in overlay maps that provide additional information on top of general topo maps, so in my case just avoiding the FID of the Garmin commercial products and the topo sets from this website will let me avoid problems. A similar question relates to numbering the individual map tiles. From what I've read, they have to be distinct across all maps loaded into the download? How do you avoid conflicts?

What is the impact of the Product Code within the Mapset?

[maps4gps]

A google search listed a Garmin product FID list - none of our mapsets seam to be included.
There was a website doing that about 5+ years ago, but was 'discontinued' about 4 1/2 + years ago.  There are also a lot of mapsets available from map authors that are not listed on gpsfiledepot. 

I do not remember a post about a FID conflict, but there may have been one.  Certainly there will be conflicts in the future as more people get into map authoring.

Since there may to thousands or even tens of thousands of tiles within a mapset, there certainly will be conflicts there also. 

With only 4 (+) digits for FID and 8 for tiles, conflicts are just something we will have to live with.