Download a map

Everything the app does offline comes out of one file per region. Getting that file onto the device is the only part of using Navzeno that needs a network.

Choosing a region

Open the Downloads tab. You get a list of countries — Canada first — each showing how many regions it holds and how much data that is. Tap one to see its regions.

Each region shows its size and one of three states:

• A Download button — it is published and ready.
• Coming soon — it is on our roster and has not been built yet. Nothing to download, and the app will not pretend otherwise.
• Open and a trash button — you already have it.

Pick the province or state you are actually travelling in. Regions are whole provinces, so one is usually enough for a trip; two neighbouring ones are normal if you are near a boundary.

You can browse the full catalogue, with real sizes and build dates, on the Maps page before you install anything.

About the sizes

A region carries the map’s shapes, every name search looks through, and the road graph routing walks — all of it, at full detail, for the whole province. Prince Edward Island is tens of megabytes. Ontario is a couple of gigabytes.

That size is the price of never needing a signal. Download on Wi-Fi, plugged in, and give a large region a few minutes.

If the download is interrupted

It resumes. Downloads are fetched in ranges and the partial file is kept, so a dropped connection, a closed app or a tunnel costs you the seconds it takes to start again — not the gigabyte you already had.

Start the same download again and it carries on from where it stopped.

Verification

Every region is published with a hash of its contents, and the app computes that same hash from the bytes as they arrive. At the end the two are compared, and the file is moved into place — in a single atomic step — only if they match.

If they do not, the file is deleted and you are told. That is deliberate: a half-corrupted map is worse than no map, because it fails in the middle of nowhere rather than in the app store. Download it again; a genuine second failure is worth telling us about.

Deleting a region

In the Downloads tab, an installed region has a trash button. Tapping it removes the file and frees exactly the size shown — there is no cache, no leftovers, no confirmation dialog either, so tap carefully.

Deleting a region does not touch your saved places. They are stored separately; see Favourites and GPX.

Updates

Every region carries a build number and a build date, both shown on the Maps page. When we rebuild a region from newer OpenStreetMap data, the build number goes up and the date moves forward.

Today, updating is manual and deliberate:

1. Check the Maps page for a newer build date than the one you installed.
2. Delete your copy in the Downloads tab.
3. Download it again.

Planned: an in-app check that tells you when the region you have is older than the published build, so you do not have to go looking. Until that lands, the app will not notice a new build on its own — and it will not re-download a region you already have, which is why deleting first is a necessary step rather than a superstition.

Storage tips

• Keep the regions you are travelling in, not the ones you might.
• Delete before a big download rather than after. A region needs its full size free while it downloads.
• A region’s size on the Maps page is exactly what it takes on the device and exactly what deleting it frees.
• Downloading over cellular is possible and rarely a good idea. Most Canadian plans and a two-gigabyte province do not mix.

Offline behaviour

The list of countries and regions is browsable with no connection — the app ships with a copy of the catalogue. Starting an actual download of course needs a network; the refresh button in the Downloads toolbar re-fetches the current catalogue when you have one.