Hi Gerd, I have compiled the same map with your patch, file is here: http://files.mkgmap.org.uk/download/225/29483020.7z Map is a bit smaller and really has less subdivisions, see comparison: fist compilation 29483019.img level 4: resolution 17, subdivisions 1 level 3: resolution 18, subdivisions 4 level 2: resolution 20, subdivisions 35 level 1: resolution 22, subdivisions 221 level 0: resolution 24, subdivisions 367 patched 29483020.img level 4: resolution 17, subdivisions 1 level 3: resolution 18, subdivisions 4 level 2: resolution 20, subdivisions 33 level 1: resolution 22, subdivisions 202 level 0: resolution 24, subdivisions 340 I can measure a small increase in zoom speed in my nuvi, like 5-10%, but this could be measurement error. -- Best regards, Andrzej