ZYRN TOPO is a mapping app for backcountry travel, field work, and search and rescue. Download topo maps, imagery, and 3D terrain before you go; track GPS; draw routes and search areas; and share team locations without an account or subscription.
A simple field workflow: choose the area, save the maps, use them offline, then share or export what you collected.
Open the map, choose topo, imagery, public lands, or your own source, then frame the route, site, or search area.
Download the maps and terrain you need so they are already on the device when the signal disappears.
Track GPS, drop waypoints, draw routes, mark hazards, record tracks, and keep coordinates visible in the field.
Share team positions when needed, print map sheets, or export files for backup and handoff after the trip or callout.
Most map apps are great until you need a layer that was never downloaded, your route leaves coverage, or the team needs to work from the same map. ZYRN TOPO keeps the important parts on the device.
Draw a box, choose zoom levels, and save topo maps, imagery, vector maps, or terrain. The map is already on the device when the network disappears.
Topo, imagery, public lands, USFS roads, wetlands, contours, hydrography, weather radar, wildfire perimeters, UTM/MGRS, and custom PMTiles live in one map.
For SAR and group field work, share locations, map objects, notes, drones, or ATAK CoT through P2P, LAN, radio mesh, or local bridges when cell service is unreliable.
Good field software should feel calm, fast, and honest. ZYRN TOPO is shaped around the problems that show up when the trailhead, search area, or work site is far from reliable service.
Saved maps, terrain, waypoints, drawings, and tracks stay local so the app still has value when the device is offline.
Switch between topo, imagery, public lands, contours, weather, wildfire, and SAR-style map objects without rebuilding your plan in another app.
Large actions, clear panels, and focused map tools matter when you are moving, wearing gloves, or checking a phone in bad light.
Export tracks, objects, team rosters, and map data for review, backup, printing, or use with other mapping tools.
It is a navigation aid, not a replacement for training, paper backups, a PLB, or a satellite messenger in high-risk terrain.
Use it for planning routes, saving offline areas, marking search zones, recording tracks, and keeping a simple shared map when service is weak or gone.
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, topo maps, imagery, and durable on-device basemaps for travel 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.
Draw search areas, record tracks, mark clues, organize periods, and share team locations over P2P, LAN, or radio mesh with no cellular dependency.
ZYRN TOPO stores map areas, objects, and tile archives locally on the device. No account, no server dependency, and no recurring subscription just to keep your maps available.
Save map areas as local tile archives, keep PMTiles on the device, and use cached parent tiles and preload passes so the map feels smoother when you pan, zoom, or reconnect.
Your saved maps, tracks, waypoints, and notes stay on the device unless you export or share them. No telemetry, no analytics, no account required.
Share team positions and map objects through WebRTC P2P, local LAN, Reticulum/LXMF, MAVLink telemetry, or an ATAK CoT bridge when a team needs more than a single-device map.
Everything you need to plan, navigate, mark up, save, and share maps without making the app harder to use in the field.
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.
Start in the browser when you want to try it fast, or install the Android app for the best field experience.
Google Play, APK / AAB
Min Android 7 (API 24)
Any modern browser
PWA installable
Try ZYRN TOPO in the browser for free, or install the Android app for offline maps, GPS, 3D terrain, and SAR-ready map tools in your pocket. No account, no telemetry, no subscription.
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, backcountry travel, field work, and anyone who cannot rely on cell coverage. Support development.