Index: trunk/src/org/openstreetmap/josm/tools/Utils.java
===================================================================
--- trunk/src/org/openstreetmap/josm/tools/Utils.java	(revision 19093)
+++ trunk/src/org/openstreetmap/josm/tools/Utils.java	(revision 19094)
@@ -2067,4 +2067,5 @@
      * @param s arbitrary string representing a length
      * @return the length converted to meters
+     * @throws IllegalArgumentException if input is no valid length
      * @since 19089
      */
@@ -2094,5 +2095,5 @@
                 /* NOTE: we assume -a'b" means -(a'+b") and not (-a')+b" - because of such issues SI units have been invented
                    and have been adopted by the majority of the world */
-                return (Double.valueOf(m.group(2))*0.3048+Double.valueOf(m.group(4))*0.0254)*(m.group(1).isEmpty()?1.0:-1.0);
+                return (Double.valueOf(m.group(2))*0.3048+Double.valueOf(m.group(4))*0.0254)*(m.group(1).isEmpty() ? 1.0 : -1.0);
             }
         }