Add button to recentre view

mapper/src/App.js

@@ -274,7 +274,7 @@ function Map({end, duration, slider, mapState, setMapState, setSubmenu, showDire
 	);
 }
 
-function Menu({duration, setDuration, end, setEnd, slider, setSlider, submenu, setSubmenu, showDirection, setShowDirection}) {
+function Menu({duration, setDuration, end, setEnd, slider, setSlider, submenu, setSubmenu, showDirection, setShowDirection, setMapState}) {
 	const [showRange, setShowRange] = useState(false);
 
 	const chooseDuration = (x) => {
@@ -330,6 +330,11 @@ function Menu({duration, setDuration, end, setEnd, slider, setSlider, submenu, s
 		window.location.href = window.location.pathname;
 	};
 
+	const recentreView = () => {
+		setMapState(prev => ({ ...prev, center: null }));
+		setSubmenu(false);
+	};
+
 	const range = parseSlider(end, duration, slider);
 
 	const shareRange = async () => {
@@ -480,6 +485,7 @@ function Menu({duration, setDuration, end, setEnd, slider, setSlider, submenu, s
 								/>
 								Show direction
 							</label>
+							<button onClick={recentreView}>Recentre view</button>
 							<button onClick={shareRange}>Share range</button>
 							<button onClick={resetToDefaults}>Reset to defaults</button>
 						</>
@@ -586,6 +592,7 @@ function App() {
 				setSubmenu={setSubmenu}
 				showDirection={showDirection}
 				setShowDirection={setShowDirection}
+				setMapState={setMapState}
 			/>
 
 			<Map