feat: add speed limit display

src/lib/services/TileMeta.ts

@@ -0,0 +1,49 @@
+import { map } from "$lib/components/lnv/map.svelte";
+import { lineString, pointToLineDistance } from "@turf/turf";
+
+function getFeatureDistance(f: GeoJSON.Feature, point: [number, number]) {
+	if (f.geometry.type === "LineString") {
+		return pointToLineDistance(point, lineString(f.geometry.coordinates));
+	} else if (f.geometry.type === "MultiLineString") {
+		// Compute the min distance across all parts
+		return Math.min(
+			...f.geometry.coordinates.map((coords) =>
+				pointToLineDistance(point, lineString(coords))
+			)
+		);
+	} else {
+		return Infinity;
+	}
+}
+
+export function getTransportationMeta(coord: WorldLocation) {
+	if(!map.value) return null;
+	const features = map.value.querySourceFeatures("openmaptiles", {
+		sourceLayer: "transportation"
+	});
+	const filtered = features.filter((f) => f.geometry.type === "LineString" || f.geometry.type == "MultiLineString");
+	if(filtered.length === 0) return null;
+	const nearest = filtered.reduce((a, b) => {
+		const distA = getFeatureDistance(a, [coord.lon, coord.lat]);
+		const distB = getFeatureDistance(b, [coord.lon, coord.lat]);
+		return distA < distB ? a : b;
+	});
+	return nearest ? nearest.properties : null;
+}
+
+const IMPLICIT_SPEEDS: Record<string, number> = {
+	"DE:urban": 50,
+	"DE:rural": 100, // TODO: 80 (hgv weight > 3.5t, or trailer), 60 (weight > 7.5t)
+	"DE:living_street": 7,
+	"DE:bicycle_road": 30
+}
+
+export function getSpeed(maxspeed: string): number | null {
+	if(!isNaN(parseInt(maxspeed))) return parseInt(maxspeed);
+	if(maxspeed.endsWith(" mph")) {
+		const val = parseInt(maxspeed.replace(" mph", ""));
+		if(!isNaN(val)) return Math.round(val * 1.60934); // Convert to km/h
+	}
+	if(maxspeed === "walk") return 7; // https://wiki.openstreetmap.org/wiki/Proposed_features/maxspeed_walk
+	return IMPLICIT_SPEEDS[maxspeed as keyof typeof IMPLICIT_SPEEDS] || null;
+}