From cbd0b625501760b7779de8ae6e802503130bdd9d Mon Sep 17 00:00:00 2001
From: Speeder <ek.speeder@gmail.com>
Date: Mon, 8 Jan 2024 21:33:24 +0100
Subject: [PATCH] Added an overlay that highlights curves.

---
 index.html         |  3 ++-
 map/curves.geojson |  3 +++
 map/curves.md      | 15 +++++++++++++++
 res/huroutes.js    | 39 +++++++++++++++++++++++++++++++++++++--
 4 files changed, 57 insertions(+), 3 deletions(-)
 create mode 100644 map/curves.geojson
 create mode 100644 map/curves.md

diff --git a/index.html b/index.html
index 8aefa3f..e748fa0 100644
--- a/index.html
+++ b/index.html
@@ -70,7 +70,8 @@
         'Google Map': 'Google Térkép',
         'Google Terrain': 'Google Domborzat',
         'Google Satellite': 'Google Műhold',
-        'Elevation Shading': 'Domborzat Kiemelés'
+        'Elevation Shading': 'Domborzat Kiemelés',
+        'Curvature': 'Kanyarívek'
       },
       'themes': {
         'System Theme': 'Rendszer megjelenése',
diff --git a/map/curves.geojson b/map/curves.geojson
new file mode 100644
index 0000000..40e9810
--- /dev/null
+++ b/map/curves.geojson
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:1b165e4d1985bdc10d37bba0a0890344088fbff2158f577853aba298e3ee4fba
+size 4330695
diff --git a/map/curves.md b/map/curves.md
new file mode 100644
index 0000000..8c1dedc
--- /dev/null
+++ b/map/curves.md
@@ -0,0 +1,15 @@
+# Data source
+
+Data source is from: https://roadcurvature.com/.
+
+Direct download of data is from: https://kml.roadcurvature.com/europe/hungary.c_1000.kmz.
+
+This data has been converted to geoJson with the tool: https://mygeodata.cloud/converter/kml-to-gpx.
+
+# License
+
+RoadCurvature.com is © Adam Franco.
+
+The Curvature program is © Adam Franco and is open-source software licensed under the Gnu General Public License (GPL) Version 3 or later.
+
+Curvature output data is © OpenStreetMap Contributors and are open-data provided under the terms of the Open Data Commons Open Database License (ODBL).
diff --git a/res/huroutes.js b/res/huroutes.js
index 6387650..577f331 100644
--- a/res/huroutes.js
+++ b/res/huroutes.js
@@ -27,11 +27,19 @@ const huroutes = {
             },
             // Choosable overlay sources supported in the layer selector. All are off by default.
             'overlays': {
-                'Elevation Shading': L.tileLayer('https://map.turistautak.hu/tiles/shading/{z}/{x}/{y}.png', {attribution:'&copy; turistautak.hu',minZoom:5,maxZoom: 18,zIndex:5,className: 'overlay-dem'})
+                'Elevation Shading': L.tileLayer('https://map.turistautak.hu/tiles/shading/{z}/{x}/{y}.png', {attribution:'&copy; turistautak.hu',minZoom:5,maxZoom: 18,zIndex:5,className: 'overlay-dem'}),
+                'Curvature': L.layerGroup(null, {attribution:'Curves: &copy; <a href="https://www.openstreetmap.org/copyright">OpenStreetMap</a> contributors'})
             },
             // Overlay sources that are always shown and hidden along with specific map tile sources.
             // The name of the overlay must be the same as the tile layer to which it is bound.
-            'tileOverlays': {}
+            'tileOverlays': {},
+            // Lazy-content overlay data, which is downloaded only when the user first shows it.
+            // Usage: Create an overlay under 'overlays' with an empty L.layerGroup. Create an
+            // item in 'lazyOverlays' with the same ID as the layergroup overlay. The value is
+            // a function that returns the layer that contains the data.
+            'lazyOverlays': {
+                'Curvature': (layer) => omnivore.geojson('map/curves.geojson', null, layer)
+            }
         },
         // A list of navigation service providers that can be chosen for the "navigate to" links'.
         // The default provider used is the first one.
@@ -181,7 +189,10 @@ $(document).ready(function() {
     (localStorage.overlays || '').split('|').forEach(item => {
         const overlay = overlays[item];
         if (overlay)
+        {
             overlay.addTo(map);
+            initLazyOverlay(item, overlay);
+        }
     });
     const tileOverlay = huroutes.opt.map.tileOverlays[localStorage.mapstyle];
     if (tileOverlay)
@@ -256,6 +267,8 @@ function initCtrls(tiles, overlays)
         overlays = overlays ? overlays.split('|') : [];
         overlays.push(overlay.layer.id);
         localStorage.overlays = overlays.join('|');
+
+        initLazyOverlay(overlay.layer.id, overlay.layer);
     });
     map.on('overlayremove', (overlay) => {
         var overlays = (localStorage.overlays || '').split('|');
@@ -304,6 +317,28 @@ function initCtrls(tiles, overlays)
     }, true);
 }
 
+/**
+ * Initializes data inside of a layer group on demand.
+ * @param {string} id The overlay identifier.
+ * @param {object} layerGroup A Leaflet layerGroup object to which the data is added.
+ */
+function initLazyOverlay(id, layerGroup)
+{
+    try {
+        if (layerGroup.getLayers().length == 0)
+        {
+            var layer = L.geoJson(null, {
+                style: {
+                    color: '#BB0',
+                    opacity: 0.9,
+                    weight: 1.5
+                }
+            });
+            layerGroup.addLayer(huroutes.opt.map.lazyOverlays[id](layer));
+        }
+    } catch { }
+}
+
 /**
  * Loads route data into the web application.
  * @param {object} data The huroutes database.