Hi, I'm trying to generate a map of Italy using house numbers option (--x- housenumbers) with latest mkgmap (r2494). I see this output traces: java.lang.IllegalArgumentException at uk.me.parabola.imgfmt.app.BitWriter.putn(BitWriter.java:89) at uk.me.parabola.imgfmt.app.net.NumberPreparer.writeInitialValue (Number Preparer.java:174) at uk.me.parabola.imgfmt.app.net.NumberPreparer.fetchBitStream (NumberPre parer.java:69) at uk.me.parabola.imgfmt.app.net.RoadDef.writeNet1(RoadDef.java:203) at uk.me.parabola.imgfmt.app.net.NETFile.write(NETFile.java:66) at uk.me.parabola.mkgmap.build.MapBuilder.makeMap(MapBuilder.java:220) at uk.me.parabola.mkgmap.main.MapMaker.makeMap(MapMaker.java:97) at uk.me.parabola.mkgmap.main.MapMaker.makeMap(MapMaker.java:61) at uk.me.parabola.mkgmap.main.Main$1.call(Main.java:201) at uk.me.parabola.mkgmap.main.Main$1.call(Main.java:198) at java.util.concurrent.FutureTask$Sync.innerRun(Unknown Source) at java.util.concurrent.FutureTask.run(Unknown Source) at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source) at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) at java.lang.Thread.run(Unknown Source) Exiting - if you want to carry on regardless, use the --keep-going option and the gmapsupp.img is not created at all. Trying to debug a little bit, i found that the problem seems to be related to this OSM element: <relation id="2198742" user="Pab09" uid="178610" visible="true" version="2" changeset="13345939" timestamp="2012-10-03T11:17:51Z"> <member type="way" ref="31563508" role="outer"/> <member type="way" ref="165015469" role="outer"/> <tag k="addr:housename" v="Hidron"/> <tag k="addr:housenumber" v="055892500"/> <tag k="addr:postcode" v="50013"/> <tag k="addr:street" v="Via di Gramignano"/> <tag k="leisure" v="sports_centre"/> <tag k="name" v="Hydron"/> <tag k="sport" v="swimming"/> <tag k="type" v="multipolygon"/> </relation> As you can see, addr:housenumber is not a valid house number (in fact it seems to me a telephon number !). However, there is, possibly, a missing check on what is supposed to be a valid housenumber (probably a sort of sanity check is needed: not all numbers could be used as house numbers, at least in relation to garmin img format limitations). I'm not sure, but I think the same problem is present with other OSM element, at least, in Italy. Thank you to all of you for your attention and for your excellent work ! ggalli