ZYRN TOPO is an offline-first topographic mapping and team-coordination platform for field operations — 0.7.9 brings a redesigned Settings screen, on top of a refreshed enterprise-grade interface, a live weather widget, elevation profiles, averaged survey waypoints, an on-screen UTM/MGRS grid, use-any-map-as-an-overlay, and field-data overlays (PLSS survey grid, USFS roads/trails, wetlands, contours, watersheds, weather radar, and active wildfire perimeters), plus a current Android beta APK for sideload testing.
Teams depend on ZYRN TOPO where connectivity is unreliable or absent — search-and-rescue, field research, and resource management that cannot afford to lose the map when the network drops.
Route planning, GPS tracking, 3D terrain, and slope-angle analysis that remain fully available outside network coverage.
BLM and USFS boundary overlays, land-status reference, and durable on-device basemaps for work beyond the road network.
Precise positions in DD, DMS, DDM, UTM, and MGRS, track recording, point elevation, and complete on-device map coverage for remote sites.
Assign operational periods, draw search areas, record tracks, and coordinate field units in real time over P2P, LAN, or radio mesh — with no cellular dependency.
ZYRN TOPO has no backend. Map data, objects, and tile archives are stored locally on the device — nothing to provision, nothing to authenticate against, and no recurring cost.
Map tiles, objects, and PMTiles archives are stored on-device in OPFS and IndexedDB. The cache pass adds bounded preloading, parent-tile fallback, persistent-storage requests, and reconnect re-warming so maps feel smoother online and offline.
All data stays on the device — no telemetry, no analytics, no third-party processing. A single purchase covers Android and the web application, including every future release.
Coordinate teams over WebRTC P2P, local LAN, Reticulum LoRa mesh, and MAVLink telemetry, with a bidirectional ATAK CoT bridge. Redundant transports keep units in sync across any operating environment.
A complete operational toolset — mapping, 3D terrain, positioning, drawing, offline storage, data interchange, and team synchronization — engineered to function without network connectivity.
addProtocol('pmtiles') renderingvector_layers metadata.pmtiles files stored on devicekind: 'dem' — auto-used when 3D engages23 base layers, 15 analytical overlays, and a catalog of 1,345 imagery sources. Any region — including 3D terrain elevation — can be stored as a local .pmtiles archive with no eviction and no cache dependency.
Plus 1,345 more sources from the OSM Editor Layer Index, filterable by country and type — added with one tap from the in-app Browse Imagery Catalog.
The same build runs on Android and as an installable web application, with no platform-specific feature gaps.
Google Play, APK / AAB
Min Android 7 (API 24)
Any modern browser
PWA installable
One purchase. Every platform, every capability, and every future release — with no subscription, no account, and no cloud dependency.
Prefer Google Play when available. The beta APK is provided for Android sideload testing and may require enabling installs from your browser.
Works in Chrome, Firefox, Edge, and Safari. No sign-up required.
Built for search-and-rescue, field teams, and operations that cannot rely on connectivity.