Ole-Morten Duesund
27cad094e7
Android app (Kotlin) that locates the nearest public shelter (tilfluktsrom) in Norway. Designed for offline-first emergency use. Features: - Downloads and caches all 556 Norwegian shelter locations from Geonorge - GPS-based nearest shelter finding with distance and bearing - OSMDroid map with offline tile caching for surroundings - Large directional compass arrow pointing to selected shelter - Compass sensor integration for real-time direction updates - Shows 3 nearest shelters with distance, capacity, and address - Toggle between map view and compass/arrow view - Auto-caches map tiles on first launch for offline use - Weekly background data refresh with manual force-update - i18n: Norwegian Bokmål, Nynorsk, and English Technical: - EPSG:25833 (UTM33N) → WGS84 coordinate conversion - Haversine distance and bearing calculations - Room database for shelter persistence - Fused Location Provider for precise GPS - Sensor fusion (rotation vector with accel+mag fallback) for compass Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
43 lines
1.7 KiB
Markdown
43 lines
1.7 KiB
Markdown
# Tilfluktsrom - Norwegian Emergency Shelter Finder
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## Project Overview
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Android app (Kotlin) that helps find the nearest public shelter (tilfluktsrom) in Norway during emergencies. Offline-first design: must work without internet after initial data cache.
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## Architecture
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- **Language**: Kotlin, targeting Android API 26+ (Android 8.0+)
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- **Build**: Gradle 8.7, AGP 8.5.2, KSP for Room annotation processing
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- **Maps**: OSMDroid (offline-capable OpenStreetMap)
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- **Database**: Room (SQLite) for shelter data cache
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- **HTTP**: OkHttp for data downloads
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- **Location**: Google Play Services Fused Location Provider
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- **UI**: Traditional Views with ViewBinding
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## Key Data Flow
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1. Shelter data downloaded as GeoJSON ZIP from Geonorge (EPSG:25833 UTM33N)
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2. Coordinates converted to WGS84 (lat/lon) via `CoordinateConverter`
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3. Stored in Room database for offline access
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4. Nearest shelters found using Haversine distance calculation
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5. Direction arrow uses device compass bearing minus shelter bearing
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## Data Sources
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- **Shelter data**: `https://nedlasting.geonorge.no/geonorge/Samfunnssikkerhet/TilfluktsromOffentlige/GeoJSON/...`
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- **Map tiles**: OpenStreetMap via OSMDroid (auto-cached for offline use)
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## Package Structure
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```
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no.naiv.tilfluktsrom/
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├── data/ # Room entities, DAO, repository, GeoJSON parser, map cache
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├── location/ # GPS location provider, nearest shelter finder
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├── ui/ # Custom views (DirectionArrowView), adapters
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└── util/ # Coordinate conversion (UTM→WGS84), distance calculations
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```
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## Building
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```bash
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./gradlew assembleDebug
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```
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## i18n
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- Default (English): `res/values/strings.xml`
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- Norwegian Bokmål: `res/values-nb/strings.xml`
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- Norwegian Nynorsk: `res/values-nn/strings.xml`
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