As far as I understood, not every type of point responds to the “resolution” setting within the points style file for mkgmap.
Railway stations (code 0x2f08) for example disappear at zoom levels higher than 500 m, even if the resolution value in the points file is lowered. This is a problem, because one might want to find a railway station at low resolutions like 2 km.
A solution could be to use a diffent code and define a railway station icon in the typ-file for this code. But only some point codes seem to have the ability that their symbols are shown at lower zoom levels (at least on my eTrex Vista HCx). I have tested the following on the eTrex with mkgmap-r2049:
0x2100 : visible at lower resolutions, but a long word (“Anschlussstelle” in german settings) is written in front of the stations name
0x4500 : visible only up to 500 m
0x1200 : visible only up to 500 m
0x9000 : no name is shown on mouse hover
Does anyone know a (free) point code, whose simbol can show up at 2 km zoom and shows the points name when touched by the mouse?
Resolution 24 wouldn’t work, because that would only show up on level 0. (Highest Resolution)
Resolutions 17 and 10 aren’t defined in your map style.
Try Resolutions 20, 18, and 16. They are defined in your list above.
Garmin has decided to render some pois only at the highest zoom to prevent cluttering.
This is firmware dependend and cant be controlled by mkgmap.
So if you want to change it try another type, maybe 0x5001?