I am using the mkgmap option --add-pois-to-areas to see all the supermarkets on my garmin. Now I found a way to also see railway stations at lower resolutions. Unfortunately, lots of them appear in the map, although they are only “light_rail” stations (which should be filtered not to show up by my points style). The problem is, that even if ligh_rail=yes is set for the POIs in OSM, there sometimes is a polygon railway station building only with the tag railway=station. For these objects, a POI is generated only with railway=station and a “big” railway station symbol is produced by the points style.
Is it possible to completely remove a polygon (or to remove its railway=station tag) by the polygons style, BEFORE it is translated into al POI by the --add-pois-to-areas option?
BTW: Is there a comprehensive description how to use mkgmap? (This here http://wiki.openstreetmap.org/wiki/Mkgmap/help/style_rules seems not to answer many questions.) Also the text fragments delivered with the mkgmap-downloads do not explain enough.