I'm getting a weird behaviour: I merge <5MB pbfs, when using osmium I get a 8MB img file while with osmosis it is less than 4MB! The latter seems fine since the initial pbfs are less than 5MB. I'd like to use osmium in my scripts since it performs better. Am I doing something wrong? Thanks to anyone that could shed some light on this! # input pbfs -r--r----- 1 enrico enrico 4673440 Jun 10 21:50 malta-latest.osm.pbf -r--r----- 1 enrico enrico 15376 Jun 10 21:50 Malta_lon14.03_14.74lat35.65_36.00_view3.osm.pbf -r--r----- 1 enrico enrico 8300 Jun 10 21:50 Malta_lon14.03_14.74lat36.00_36.18_view3.osm.pbf # using osmium $ osmium merge *.pbf -o all.pbf $ java -jar ../splitter/splitter.jar --mapid=70000001 all.pbf $ java -jar ../mkgmap/mkgmap.jar --family-id=10030 --product-id=1 --route --remove-short-arcs --bounds=../bounds.zip \ --precomp-sea=../sea.zip --location-autofill=is_in,nearest --draw-priority=20 --gmapsupp --index --housenumbers 7000*pbf -rw-rw-r-- 1 enrico enrico 4695873 Jun 10 21:54 all.pbf -rw-rw-r-- 1 enrico enrico 428866*9* Jun 10 21:54 70000001.osm.pbf -rw-rw-r-- 1 enrico enrico *7925760* Jun 10 21:55 70000001.img -rw-rw-r-- 1 enrico enrico *8171520* Jun 10 21:55 gmapsupp.img # using osmosis $ ../osmosis/bin/osmosis --rbf ./malta-latest.osm.pbf \ --rbf ./Malta_lon14.03_14.74lat35.65_36.00_view3.osm.pbf \ --rbf ./Malta_lon14.03_14.74lat36.00_36.18_view3.osm.pbf \ --merge --merge --wb all.pbf $ java -jar ../splitter/splitter.jar --mapid=70000001 all.pbf $ java -jar ../mkgmap/mkgmap.jar --family-id=10030 --product-id=1 --route --remove-short-arcs --bounds=../bounds.zip \ --precomp-sea=../sea.zip --location-autofill=is_in,nearest --draw-priority=20 --gmapsupp --index --housenumbers 7000*pbf -rw-rw-r-- 1 enrico enrico 4680030 Jun 10 22:03 all.pbf -rw-rw-r-- 1 enrico enrico 428866*8* Jun 10 22:04 70000001.osm.pbf -rw-rw-r-- 1 enrico enrico *3547136* Jun 10 22:04 70000001.img -rw-rw-r-- 1 enrico enrico *3788800* Jun 10 22:04 gmapsupp.img Using very latest splitter, mkgmap, and osmium (tried with 1.10 and 1.12 compiled from source...). Note both gmapsupp.img seems to work just fine on the garmin device.