<p>It looks like the gpx builder fails when there are no queries in the search area.</p>

<p>E.g. <a href="http://api.openstreetmap.org/api/0.6/notes.gpx?bbox=-170.65094,51.312159,-170.374908,51.669148">http://api.openstreetmap.org/api/0.6/notes.gpx?bbox=-170.65094,51.312159,-170.374908,51.669148</a> fails with ActionView::Template::Error: can't convert nil into String</p>

<p style="font-size:small;-webkit-text-size-adjust:none;color:#666;">—<br>Reply to this email directly or <a href='https://github.com/openstreetmap/openstreetmap-website/issues/234'>view it on GitHub</a>.<img src='https://github.com/notifications/beacon/uTRSc6ihLa7Shf84BpiOpt7SBBGA76UG-6mLEv_mGq82i1aZ8Llwi8rNcPQZ8X54.gif' height='1' width='1'></p>