Thanks for reporting this John. The problem is due to a relation that has a member without a "role" tag. I've checked in a fix (r90) that will now handle this situation correctly. JT> Exception in thread "main" java.lang.NullPointerException JT> at JT> uk.me.parabola.splitter.OSMWriter.writeString(OSMWriter.java:163) JT> at uk.me.parabola.splitter.OSMWriter.write(OSMWriter.java:113) JT> at JT> uk.me.parabola.splitter.SplitProcessor.writeRelation(SplitProcessor. JT> java:246) JT> at JT> uk.me.parabola.splitter.SplitProcessor.endRelation(SplitProcessor.ja JT> va:174) JT> at JT> uk.me.parabola.splitter.OSMParser.endElement(OSMParser.java:218) JT> at JT> uk.me.parabola.splitter.AbstractXppParser.parse(AbstractXppParser.ja JT> va:44) JT> at uk.me.parabola.splitter.Main.processOsmFiles(Main.java:346) JT> at uk.me.parabola.splitter.Main.processMap(Main.java:335) JT> at uk.me.parabola.splitter.Main.writeAreas(Main.java:319) JT> at uk.me.parabola.splitter.Main.split(Main.java:156) JT> at uk.me.parabola.splitter.Main.main(Main.java:93)