How it works offline
Offline is not a mode. It is how it was built.
Plenty of apps have an offline mode, which usually means a cache of the last few things you looked at and a spinner for everything else. This is the other thing. There is no server on the other end of it, so there is nothing to lose when the network goes.
01Sequence
The path a question takes
Every step happens on the handset.-
You ask, in plain language
No keywords, no filenames, no folder structure to learn. You type the question the way you would say it out loud.
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The phone searches its own library
An index built over every page of the installed documents runs on the device. It matches on wording and on meaning together, so a question about a scald finds the burn chapter even if nobody wrote the word scald.
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The passages go to the model
The best matching passages are handed to a language model that is also on the phone. It is reading those passages, not recalling something it absorbed during training.
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The answer comes back with its sources
The answer names the document and page behind each part of it. Those citations are links into files already sitting on your device, which is why they open instead of failing.
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You check the page
This is the step the whole design exists for. Read the source. Decide for yourself. The app is a fast way to find the right page, not a reason to stop reading pages.
- Question text
- Never leaves the device
- Search index
- On device
- Documents
- On device
- Language model
- On device
- Map tiles
- On device
- Position fix
- GPS receiver
- Outbound requests
- None
Because nothing is sent anywhere, nothing you ask it can end up anywhere. That is a side effect of the architecture rather than a privacy policy, which is the version worth having.
02Position
Maps and GPS, with the network down
The part people assume cannot work, and it can.GPS is often confused with mobile data because phones use both at once. They are separate systems. The satellites broadcast, your phone listens, and it works out where it is from what it hears. Your handset never transmits to them and never needs a carrier to be involved.
What normally breaks when you lose data is not the position. It is the map, because the map was being streamed a tile at a time from somewhere else. SurvivalOps stores the maps on the phone, so the position has something to sit on.
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Vector maps
Roads, places and routing
Searchable, zoomable regional maps held as files on the device, with points of interest and routing, so you can still find a road, a name or a way through.
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Topographic sheets
Terrain and contours
Topographic coverage with elevation contours, for the questions a road map cannot answer: what the ground does, where the water goes, and what is between you and where you are heading.
03Requirements
What does need a connection
Two things, both of them before the event and neither during it.- Getting it onto the phone. The app and the library have to be downloaded once, and that download is large. Do it at home on wifi, with the phone plugged in, well before you need it. Preparedness that requires a working network on the day is not preparedness.
- Updates. New and revised documents arrive as downloads, on your schedule. Nothing expires, nothing stops working if you never update, and no check-in is required to keep using what you already have.
Everything here still runs on a battery. An answer costs power, a big library costs storage, and a phone is a phone. Charge is part of the plan, the same as water and light. We would rather say that plainly than sell you a device that does not have the problem and then hand you one that does.
04Continue