ZYRN TOPO is an offline-first topographic mapping and team-coordination platform for field operations — 0.8.0 brings a redesigned Settings screen, a weather widget that follows the map as you pan (and live weather in the Point Info tool), and an immersive fullscreen mode on Android, on top of a refreshed enterprise-grade interface, 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.
USGSEsri ArcGISOpenStreetMapMapterhorn DEMBLM / USFSReticulum MeshMAVLink / ATAK CoTCalTopo-compatible GeoJSON
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Designed for field operations
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.
Backcountry & Expedition
Route planning, GPS tracking, 3D terrain, and slope-angle analysis that remain fully available outside network coverage.
Public Lands & Resource Management
BLM and USFS boundary overlays, land-status reference, and durable on-device basemaps for work beyond the road network.
Field & Survey Teams
Precise positions in DD, DMS, DDM, UTM, and MGRS, track recording, point elevation, and complete on-device map coverage for remote sites.
Search & Rescue
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.
Operational reliability
Engineered to run where infrastructure doesn't
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.
Offline-first architecture
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.
Data ownership by design
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.
Multi-transport team synchronization
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.
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Base map layers
15
Map overlays
1,345+
Imagery sources
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Sync transports
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Core capabilities
A complete operational toolset — mapping, 3D terrain, positioning, drawing, offline storage, data interchange, and team synchronization — engineered to keep working when connectivity drops.
Incoming CoT detection events displayed as map markers
Marker color follows CoT type (friendly · neutral · hostile)
120 s stale timeout; Python bridge runs on any networked computer
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Map data and coverage
23 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.
Topo
USGS Topo
Topo
USGS Imagery + Topo
Topo
OpenTopoMap
Topo
NatGeo World
Topo
Esri World Topo
Topo
USA Topo (Historical)
Imagery
Esri Satellite
Imagery
USGS Imagery
Street
OpenStreetMap
Street
OSM Humanitarian
Street
CyclOSM
Topo
Esri World Physical
Water
Esri Ocean Basemap
Vector
OFM Liberty
Vector
OFM Bright
Vector
OFM Positron
Vector
OFM Dark
Vector
OFM Fiord
Vector
VersaTiles Colorful
Vector
VersaTiles Neutrino
Vector
VersaTiles Graybeard
Vector
VersaTiles Eclipse
Vector
VersaTiles Shadow
Overlay
Hillshade
Overlay
USGS Hydrography
Overlay
Transportation
Overlay
Hiking Trails
Overlay
Cycling Routes
Overlay
MTB Trails
Overlay
OpenSeaMap (Nautical)
Overlay
BLM Public Lands
Overlay
OpenSnowMap Pistes
Overlay
OpenRailwayMap
Overlay
OpenInfraMap Power
Overlay
Esri Reference Labels
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.
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Deploy across every device
The same build runs on Android and as an installable web application, with no platform-specific feature gaps.
Android
Google Play, APK / AAB Min Android 7 (API 24)
Web
Any modern browser PWA installable
Deploy ZYRN TOPO
One purchase. Every platform, every capability, and every future release — with no subscription, no account, and no cloud dependency.
