feat: add speed limit display

src/lib/components/lnv/Sidebar.svelte

@@ -14,6 +14,7 @@
 	import RequiresCapability from "./RequiresCapability.svelte";
 	import {
 		advertiseRemoteLocation,
+		getRoadMetadata,
 		location,
 		remoteLocation,
 	} from "./location.svelte";
@@ -27,6 +28,7 @@
 	import Progressbar from "../Progressbar.svelte";
 	import { postHazard } from "$lib/services/lnv";
 	import { fetchHazards } from "./hazards.svelte";
+	import { getSpeed } from "$lib/services/TileMeta";
 
 	const views: Record<string, string> = {
 		main: "MainSidebar",
@@ -180,6 +182,17 @@
 		{(location.speed * 3.6 | 0).toFixed(0)}
 	</div>
 {/if}
+{#if getRoadMetadata()}
+	{@const meta = getRoadMetadata()!}
+	{#if meta.maxspeed}
+		{@const maxspeed = getSpeed(meta.maxspeed)}
+		{#if maxspeed && maxspeed < 100}
+			<div id="max-speed" style="position: fixed; {mobileView ? `bottom: calc(50px + ${sidebarHeight.current}px + 10px + 2ch + 20px + 10px); right: 10px;` : "bottom: calc(10px + 2ch + 20px + 10px); right: 10px;"}">
+				{meta.maxspeed}
+			</div>
+		{/if}
+	{/if}
+{/if}
 
 <div
 	id="sidebar"
@@ -406,7 +419,8 @@
 		padding-bottom: calc(40px + env(safe-area-inset-bottom));
 	}
 
-	#speedometer {
+	#speedometer,
+	#max-speed {
 		z-index: 30;
 		background-color: hsla(0, 0%, 5%, 0.6);
 		backdrop-filter: blur(5px);
@@ -417,5 +431,12 @@
 		border-radius: 10px;
 		text-align: center;
 		width: calc(2ch + 20px);
+		height: calc(2ch + 20px);
+	}
+
+	#max-speed {
+		border-radius: 50%;
+		border: 5px solid red;
+		padding: 5px;
 	}
 </style>

src/lib/components/lnv/location.svelte.ts

@@ -1,5 +1,6 @@
 import { LNV_SERVER } from "$lib/services/hosts";
 import { routing } from "$lib/services/navigation/routing.svelte";
+import { getTransportationMeta } from "$lib/services/TileMeta";
 import { map } from "./map.svelte";
 
 export const location = $state({
@@ -39,6 +40,12 @@ export function isDriving() {
 	return _isDriving;
 }
 
+const roadMetadata = $derived(getTransportationMeta({ lat: location.lat, lon: location.lng }));
+
+export function getRoadMetadata() {
+	return roadMetadata;
+}
+
 export function watchLocation() {
 	if (navigator.geolocation) {
 		navigator.geolocation.watchPosition(

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;
+}