Silent Compass — Offline Survival Companion

NAVIGATION

State

Terrain & elevation 🏔️ Shaded relief (terrain depth)Relief strength

Tap “Check center elevation” while online. Saved readings remain available offline.

USGS topo contours and labels are shown at supported zoom levels. Shaded relief is blended using Multiply (rather than a transparent overlay) with stronger contrast; the effect varies with terrain and zoom. It is a separate downloadable map layer. Elevation is a point estimate, not a terrain survey.

🧭 My Situation

Choose an emergency situation or planned adventure to customize the map resources. Your downloads remain unchanged.

Emergency SituationChoose Your Adventure

Resource layers 🏥 Hospitals & ERs 🛡️ Military installations (restricted) 💧 Freshwater features 🚤 Boat ramps (verified type only) ✈️ Airports & airstrips (access not guaranteed) 🌲 Ranger Stations & Forest Service Offices

Hospital crosses and military shields identify mapped facilities; military sites are restricted and not public shelters. Markers come from downloaded geographic datasets, not live facility status. Ranger stations and forest offices may be closed, seasonal or unstaffed; do not assume emergency assistance is available. Water is not presumed drinkable.

Resources: checking saved data…

⬇️ Offline

Prepare before you go. Maps and resource locations are downloaded separately.

Hospitals, water, boat ramps and more for your selected state.

Selected state: South Carolina (change on Map tab)

Checking available packs…

🗺️ Offline map

Save the area currently shown on your map.

Map tiles are saved on this device. Zoom range is adjustable in Advanced Tools.

🧭 Offline readiness

Checking offline preparation…

Readiness applies to the current map view and selected state, not the entire state.

📱 Saved on this device

Checking saved resource locations…

Downloaded map coverage depends on the areas and zoom levels saved.

⚙️ Advanced Tools

Optional controls for zoom ranges, area resource refresh, import/export and storage.

Minimum zoomMaximum zoom

Map resource setup

Retrieve resources for the visible area using the existing online service.

Import resource GeoJSON

Navigate

Drag to pan; scroll or pinch to zoom; tap a marker to inspect it. GPS may work without cellular service if the device supports satellite positioning and grants permission.

🧭 Route guidance

Calculate driving, walking, or biking directions online and save them for offline reference. New routes require internet; saved directions are not live GPS navigation.

Travel mode

Driving routes can be calculated online and saved for offline reference. Walking and biking routing are not available yet.

From (address, landmark, or lat, lon)

To (address, landmark, or lat, lon)

Saved routes (available offline)

No route selected.

ROUTE PREVIEW / LOCAL DETAIL MAPZoomed view

Mini map follows the selected marker, or the center of the main map. Uses the same offline map tiles.

📍 My emergency locations

Personal places are stored locally on this device. Use general labels for sensitive supply caches; exported backups are NOT encrypted. Do not share them publicly.

Location nameCategoryMap iconStreet address (optional; requires internet to locate)

Enter an address instead of coordinates, or save both. Address lookup tries the US Census geocoder, then OpenStreetMap Nominatim, while online. Saved addresses and coordinates remain on this device.

Coordinates (lat, lon) — optional if address entered

Accepts decimal GPS coordinates, degree symbols, and N/S/E/W.

Location photo (optional)

Add a landmark photo when saving, such as a tree near a cache. Stored locally for offline viewing (8 MB maximum). Not shared with family circles yet.

Notes (optional)

Show personal locations on maps

Saved locally, available offline.

🛣️ Offline roads & elevation (new)

Download a town-sized road network and measured USGS elevation samples while online. Offline routes are calculated on your device using only downloaded roads. Roads are not checked for closures or passability.

Elevation sample grid

Sampled points are real measurements from the USGS elevation service, not a continuous DEM. Nearest-sample readings are labeled with distance and should not be treated as precise elevation at an arbitrary point.

Save landmark / address labelCoordinates or online address

Enter start/destination in the Route guidance fields above. Exact coordinates and saved labels work offline; unknown addresses require an online lookup. Select a map resource marker as destination using the existing button.

Import offline data (JSON)

Loading offline road and elevation data…

Selected location

Tap a marker.

Nearby / visible resources

Initializing map…