diff --git a/src/routes/+page.svelte b/src/routes/+page.svelte
index c05f443..805755b 100644
--- a/src/routes/+page.svelte
+++ b/src/routes/+page.svelte
@@ -8,6 +8,9 @@
 	const linesUrl =
 		"https://data.grandlyon.com/geoserver/sytral/ows?SERVICE=WFS&VERSION=2.0.0&request=GetFeature&typename=sytral:tcl_sytral.tcllignemf_2_0_0&outputFormat=application/json&SRSNAME=EPSG:4171&sortBy=gid";
 
+	let distance = +Infinity;
+	$: points = 5000 * Math.exp(-distance / 750);
+
 	onMount(async () => {
 		const L = (await import("leaflet")).default;
 
@@ -43,16 +46,28 @@
 			});
 		}
 
-		const marker = L.marker([centerLat, centerLon]);
-		map.on("click", (e) => marker.setLatLng(e.latlng).addTo(map));
+		const marker = L.marker([0, 0]);
+		map.on("click", (e) => {
+			marker.setLatLng(e.latlng).addTo(map);
+			// allow 20m of error
+			distance = Math.max(0, e.latlng.distanceTo([45.75388713, 4.84715287]) - 20);
+		});
 	});
 </script>
 
+<div id="info">
+	<span>distance: {distance}, points: {points}</span>
+</div>
+
 <div id="map"></div>
 
 <style>
+	#info {
+		height: 5vh;
+	}
+
 	#map {
-		height: 100vh;
+		height: 95vh;
 		width: 100%;
 	}
 </style>