As I posted here on 2024.12.01, I was having issues with POIs not displaying labels for some garmin devices (specifically the XT2 and Tread) when generating /img files using mp file input to mkgmap.  I did some exploration and discovered this (maybe well known but not by me):

• Each device model displays POIs differently (i.e., type 0x100 does not show the same thing). There seems to be no consistency across models (Felix echoed this in a follow-up post).

• Each model displays labels for each POI type differently (some show no label, others show small vs big text).  There seems to be no consistency across models.

• I attempted to use the custom "[_point]" feature of the mp files and mkgmap but the custom point bitmaps only work for some garmins.  Even then, it didn't help with my missing [poi] labels.

• Prior to the labels not working on the XT2 and Tread units, I always used the 0x1400 POI code type for my labels.  With a lot of cross-model experimentation I discovered a single POI code (0x1E00) will display large text on all garmin models I was able to test with (Montana 6XX and 7XX, XT, XT2, Tread).  I have no idea if this POI code will work with all garmins that support custom maps.

Questions:

• Are these issues with each model behaving differently with respect to POI types well-known?  If so, how are they gotten around by (OSM) map builders?  How can a single map be built that has POIs and labels that are consistent across more than one device.  What am I missing?  

• How does OSM handle this?  I presume that an OSM map generated for an area works on all garmin devices?  I will admit that I don't know what the OSM map limitations are across garmin models.  Does the JOSN model allow the devices POI maps to be loaded on a per-map basis?  If I were to switch to JOSN model for mkgmap input, could I get around all the device limitations I am running into with the mp file format?  Can someone recommend a good tutorial on getting up to speed on generating JOSN for simple map input to mkgmap?

• OSM uses the JOSM model to feed mkgmap.  Does that model allow for more flexibility and control than the "mp" input file model?  I presume the MP file format is obsolete.

• Is there any better documentation for the MPO format than the CGPSMAPPER pdf file floating around on the internet?

• Can anyone recommend either a different website or people whom I may contact for further help with any of this?

Any and all help is appreciated.