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OFFLINE MAPS

Offline maps for field teams that work where the signal stops.

Offline maps in Sinkaos come as part of a mission pack: the area, the layers, the plan and each person’s tasks, downloaded before anyone leaves. With no bars on the phone, people still see the ground, their work and where the others were last seen.

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THE GREY GRID

The map app shows a grey grid exactly where the team is working.

Most map apps assume a connection. They cache whatever you happened to look at, and when you zoom into the valley where the search sector actually is, the tiles never load. The sector boundaries someone drew last night live on a laptop at the command post, and the photo of the printed map on the group chat is too blurry to read a grid reference from.

Paper maps still work, but they cannot show who is where or take a report, and every change has to be read out over the radio and redrawn by hand. And coverage is worst in the places where the work is: forests, gorges, cellars, the far side of a flooded area.

SEARCH DAY

From the evening before to a ridge with signal again.

  1. 18:00
    The area is drawn once
    The coordinator draws the search area, splits it into sectors and adds the access tracks, the meeting point and a known hazard. She picks the basemaps and an orthophoto layer for the area.
    SectorsBasemapsLayers
  2. 19:30
    Each phone downloads its pack
    Every searcher’s phone fetches a mission pack with the offline map of the area, the layers, the plan, that person’s tasks and the team list. A dog handler’s pack differs from a drone pilot’s. The coordinator sees whose pack is on the device and whose is still downloading.
    Mission packsPack status
  3. 07:10
    Into the dead zone
    Team 3 walks into a gorge with no coverage. The map, the sector boundary and their tasks are all on the phone. They read a position in MGRS off the screen and record an observation with a photo; it waits in the queue.
    No signalMGRSQueue
  4. 08:25
    A new route without a connection
    A footbridge is down. The team lead marks it as closed and calculates another way round from road and path data stored on the phone.
    Offline routingClosures
  5. 09:02
    Back on a ridge, the picture catches up
    The phone finds signal. The observation, the closure and the track go out, oldest first, and land on the timeline at the time they happened, marked as late.
    SyncTwo timestamps
Mission pack on a searcher’s phone with no service: offline map of the area, mission plan, own tasks, team and contacts, keys, documents and three changes waiting to send.
A searcher’s mission pack with no signal. Demo data.
MISSION PACKS

Maps that are already on the phone when the network goes.

Vector and raster maps offline

Download the area as vector or raster maps, including tiles from your own tile servers.

A basemap catalogue

Publish a set of named basemaps for your organisation, so everyone switches between the same topographic map, orthophoto or street map.

One pack per person

Offline maps arrive together with the plan, the person’s tasks, the team list and documents, scoped to their role.

Coordinates people actually use

WGS 84, UTM, MGRS and others, each shown in the format the reader prefers. Paste a coordinate to find it.

Search without signal

An offline geocoder finds places on the device. Offline routing calculates new routes from stored road data, and takes closures and hazards into account.

Buildings and floors too

Offline site packages carry an area of your persistent atlas or a building with its floor plans into the field.

Your own layers

Imagery and map services such as WMS, WMTS and GeoTIFF, plus KML, GeoJSON and GPX data, sit as layers with their own order, opacity and permissions.

WITHOUT SIGNAL

What the phone shows offline, and what waits for the link.

ON THE PHONENO SIGNALWHEN IT RECONNECTS
MapFull map of the pack area, all layers in the packNewer layers and edits download
Own positionRecorded on the deviceTrack uploads and fills the gap
Others’ positionsLast known position, with its ageLive again
Reports and photosCreated as normal, held in the queueSent in order, oldest first
RoutingNew routes from stored road dataOnline routing service available again
Camera and sensor feedsNot available, last value shown with its timeLive again

The full table is on How it works.

LIMITS

What offline maps in Sinkaos do not do.

Areas must be packed in advance
The phone has the map of the pack area. If a team walks far outside it with no signal, there is nothing new to download until a link appears. Plan the area generously.
Nothing live from others while offline
New reports from other teams, camera feeds and sensor values arrive only when there is a connection. Positions of others show as last known, with their age.
Storage and battery are finite
Large areas at high detail take space. Tracking profiles balance track detail against battery, and admins see storage by data type.
It is not a dispatch system
Sinkaos is not a certified emergency dispatch or public warning system, and it does not replace radio for urgent voice traffic.
TYPICAL USES

Where teams use offline maps.

Missing-person searchesMountain rescueFlood responseForest firesRemote infrastructure sitesFestivals on farmlandTrail racesHumanitarian distributionClosed exercisesUnderground car parks
QUESTIONS

Before your first operation without signal.

Do people have to download maps themselves?
No. The operator defines the area and layers in the operation, and each member’s phone downloads its mission pack. The operator sees who is ready and who is still downloading.
Can we use our own maps?
Yes. Add your own tile servers, WMS or WMTS services, orthophotos, drone maps and KML, GeoJSON or GPX data. Publish the ones your teams use as a basemap catalogue.
Can a whole command post work without internet?
Yes. A disconnected node on a laptop or small server serves the team over local Wi-Fi and syncs with other nodes when a link exists, even a slow satellite one.
Which coordinate formats are supported?
WGS 84, UTM, MGRS and others. Each person chooses the format they read best; see the MGRS entry in the glossary for how grid references work.
What happens to reports written without signal?
They are saved on the phone and sent when a link appears, oldest first. Each keeps the time it happened and the time it arrived, so late reports land in the right place on the timeline.
Does it work on iPhone and Android?
Yes, both, plus a web app for the operator. Offline maps and mission packs work on both phone platforms.
RELATED

Got a search area or a site with no coverage?

Tell us where you work. We’ll set up the first operation with you, maps included.