Digital Twin Hobart
GovHack-winning 3D city model of Hobart that works entirely offline. PMTiles on S3 replaces traditional tile servers — 60% faster initial loads, zero per-request hosting costs, and full functionality in disconnected field environments.
Event
GovHack / Tasmania
Key Results
GovHack Digital Twin Challenge
Offline after initial 8MB cache
Faster initial load vs. traditional tile server
Built in a single hackathon weekend
The Challenge
Emergency responders and field surveyors need 3D city models in exactly the places where connectivity is worst — disaster zones, remote infrastructure sites, underground facilities. Traditional digital twins fail the moment the network drops.
Key challenges included:
- Existing solutions require constant connectivity — useless in field emergencies
- 3D building datasets too large for naive caching strategies
- Traditional tile servers add 200-400ms latency per tile request
- Field teams in rural Tasmania often have zero cellular coverage
- Per-request tile hosting costs scale linearly with user growth
Innovation Focus
GovHack Tasmania challenged teams to build innovative solutions for government in 48 hours. We focused on a real gap: field operators who need spatial data precisely where connectivity does not exist.
Offline-First Design
Full functionality without connectivity
3D City Model
Interactive building visualization
Our Solution
PMTiles packages all map tiles into a single seekable archive on S3 — no tile server needed. Service workers cache the 8MB archive locally after first load, enabling full 3D city navigation with zero network dependency. Built in 48 hours at GovHack Tasmania.
PMTiles Architecture
All tiles packaged into a single seekable archive on S3. HTTP range requests serve individual tiles from the archive — no tile server process, no per-request compute.
Three.js Visualization
Three.js renders Hobart buildings, terrain, and infrastructure as interactive 3D geometry. Orbit, zoom, and inspect individual structures at 60fps.
Service Worker Caching
Service workers cache the 8MB PMTiles archive after first visit. Every subsequent session — online or offline — loads from local storage in under 200ms.
MapLibre Integration
Integrated MapLibre GL JS for high-performance 2D/3D map rendering with custom styling.
AWS S3 Hosting
Static files on S3 with CloudFront CDN. No servers to manage, no scaling concerns — hosting costs stay under $2/month regardless of traffic.
Progressive Loading
Visible viewport tiles load first, surrounding tiles prefetch in background. First meaningful paint in under 1.5 seconds on 4G connections.
Project Impact
Technical Innovation
- Proved PMTiles viability: 60% faster tile delivery than traditional server at 1/10th the hosting cost
- 8MB cached archive serves the entire Hobart CBD in full 3D offline
- First offline-capable digital twin demonstrated at a GovHack event nationally
- Architecture is city-agnostic — swap the PMTiles archive and it works for any municipality
Recognition & Future
- Won GovHack Digital Twin Challenge — 1st place among 12 competing teams
- Selected for national GovHack showcase presentation in Canberra
- Emergency services expressed interest in offline capability for disaster response
- Architecture adopted as reference pattern for subsequent government spatial projects