Heavenly Grandchild's Detour Map 🌋 | Footprints of the Kirishima Expedition

🗺 3D Stereoscopic Map of GSI Tiles (3D/Flat · Elevation Adjustment · Standard/Photo/Terrain) + Elevation Display
📍 Guide pins for exhibition venues, mythological spots, accommodations, and more pre-loaded
👣 Register your own detour spots with Google login (categories, photos, comments, links, X)
❤️ Like/Been there reactions
🔎 Place name search (GSI) + Nearby search (OSM: convenience stores, hot springs, roadside stations…)
🐈 Pet Tora-chan and Wajiro-chan—they'll meow and respond to you (with sound ON)

【How to Use】
① Drag the map freely. Switch between 3D and flat views, adjust tilt and "elevation boost" to enjoy Kirishima's topography in 3D (elevation at screen center is also displayed).

② Tap the pre-loaded guide pins to read explanations about exhibition venues, mythological sites, hot springs, accommodations, and more.

③ Add your own detour spots with "+ Your Registration."
　・Tap directly on the map to specify a location, or
　・Paste a Google Maps share link into the search bar (place name auto-fills)
　→ Add categories, photos, a comment, and links, then register. You can edit later.

④ Give "likes" or "been there" reactions to spots you're interested in.

⑤ Search for place names in the search bar, or use buttons to find nearby convenience stores, hot springs, and roadside stations.

　On smartphones, add to home screen to use it full-screen like an app.

Added 2026/7/9
⑥ Works offline 📴
　Records of signal-dead spots are often taken in areas without reception. This app:
　・Displays maps (including 3D elevation) for previously viewed areas even offline
　・Saves offline registrations to your device using GPS to capture your current location
　・Automatically sends to the shared map when signal returns (managed with ⏳ unsync badge)
　The trick is to take a look around Kirishima before your expedition.

【Technical Notes】
・Map: GSI map tiles (standard/photo/terrain) + elevation API. 3D topography is rendered using elevation data (AWS Terrain Tiles). Map engine is MapLibre GL.
・Nearby search: OpenStreetMap (Overpass API)
・Google Maps share link → coordinate conversion: Netlify Functions (server-side processing)
・Login, post saving, photos: Supabase (Google authentication / DB / Storage)
・Hosting: Netlify
・Built entirely with a single HTML file + free services only.

Added 2026/7/9
・Offline support: Service Worker caches the app itself and viewed map tiles (updates prioritize network for always-current data). Offline registrations are saved to localStorage and auto-sync to Supabase when back online.

Added 2026/7/11
When articles pop up, the title and search window are positioned above to prevent the article from being hidden.