Offline downloads — take a network with you

The Field App has always kept what you looked at, so a screen you opened this morning is still readable this afternoon with no signal. Downloading a network is the other half: you choose a trail system before you leave, the app pulls it down, and it is there whether or not you happened to open the right screen first.

When to download

Download when you are heading somewhere with no signal and you want certainty rather than luck. The everyday cache covers the screens you happened to visit; a download covers a trail system whether you visited it or not.

It is also worth doing before a day on a weak connection, not just no connection. Downloaded content is used without asking the network at all, so a bad signal cannot make it slow — see Using a download.

Downloading a network

Open the Field App, go to the storage screen, and tap Download a network. The sheet is titled Download for offline.

1. Pick your networks. Tap one or more from the Networks list. Everything below recalculates as you change the selection.
2. Review what you'll download. The What you'll download list is a bill of materials — every category, what it holds, and what it costs in megabytes.
3. Adjust the expensive parts. Photos and maintenance tasks each have None / partial / All choices, and infrastructure, points of interest and terrain can be switched off entirely.
4. Check the total, then tap Download.

While it runs the footer shows Saving N of M files… with a Stop button. Stopping leaves what has already been saved in place; running the same download again picks up from there rather than starting over.

What you can include

Category	Choices	Notes
Trails	Always included	Names, geometry, and status. The smallest part of any download.
Maintenance tasks	None / Open only / All	"All" includes resolved and closed history, which on an old network is most of the weight.
Photos	None / Open tasks only / All	Downscaled copies, roughly a tenth the size of the originals. Full resolution stays online.
Infrastructure	Include or not	Bridges, signs, culverts and the rest, with their custom fields.
Points of interest	Include or not	Waypoints, hazards, features.
Contours & slope shading	Include or not	Elevation lines and slope coloring. See Terrain analysis.
Planner recordings	Off by default	Proposed and recorded lines with their geometry.
Projects	Off by default	Active work groupings and the tasks linked to them.
Inventory	Off by default	Stock catalog and storage locations.

The last three behave differently from everything above them, in two ways worth knowing.

They are organization-wide. Trails, tasks, infrastructure and points of interest are scoped to the networks you picked; planner recordings, projects and inventory are not — those rows belong to the organization rather than to a trail system. So their size does not move as you add networks, and two downloads covering different networks each carry their own copy.

They are off unless you switch them on. A crew downloading a trail system wants tasks, photos and a readable map; putting the whole planner corpus into every download would charge everyone for something most never open. Turn them on when you need them.

One limitation on planner recordings: a download carries the list and each line's shape — enough to browse them and see them on the map — but not the full elevation profile, which is fetched per recording and needs a connection.

Terrain goes offline because we generate it ourselves from open elevation data rather than licensing it. What decides whether a map layer can be downloaded is never its size — it is whose bytes they are.

Which is why organizations on the TrailsIQ map get the base map itself in a download. Those tiles are ours, harvested around the trails and stored on our own disk, so no provider's terms are in the way of packaging them. Roads, paths, water and place names come with the trip and draw offline exactly as they do with a signal — including the Base map style picker, since all three looks are downloaded alongside the tiles they share. See The TrailsIQ map.

What cannot be downloaded

Satellite imagery, always. It is a provider's, at every price.

The base map, on an organization that renders through Mapbox. Those tiles are Mapbox's, and their terms cover the caching that happens as you pan around a map but not bulk-downloading an area in advance. Tiles you have already looked at stay available offline; ground you have never panned over will not — so pan around the area you care about while you still have signal.

This is a licensing limit, not a technical one, which is exactly why it lifts on the TrailsIQ map: the same download, the same code, tiles nobody else owns. The row in the sheet says which position you are in rather than a flat "no", and prices the download either way.

Where tiles are missing, trails, markers, contours and slope shading draw on a plain background. The map still works; it has no backdrop.

One thing to know on the free engine: the base-map row can also read Nothing harvested for this area yet. That is not a license problem. Tiles are collected around trail lines as they are saved, and a network added minutes ago may not have any yet — the row still quotes what it would come to, so you can tell "not yet" from "not for you".

Using a download

There is no offline mode to switch on. Downloaded content is simply used when it applies.

One consequence surprises people: a download is used even when you are online. That is deliberate. A downloaded terrain tile is byte-for-byte what the server would have sent, so fetching it again would buy nothing and cost a wait — and the wait is worst exactly where it matters, on a weak signal at the far end of a valley. Reading from the device is instant regardless of what the connection is doing.

The one thing to know about that: if terrain is regenerated on the server after you downloaded, your device keeps the older copy until you download again. Nothing else works this way, because everything else has a new identity when it changes.

Things added after you downloaded

A download is a snapshot. Nothing added afterwards is hidden by it — it simply isn't in it yet.

• Online, everything new appears normally. A task filed after your download shows up, its photos load, and terrain over new ground draws from the server. The download never shadows anything newer.
• Offline, anything added after the download is missing until you download again.

The sheet tells you when a download has fallen behind. Open it with a connection and each saved download under On this device is checked against the live network. One that has gone stale says so — "12 new files · 3.4 MB" — with an Update button beside it.

You do not have to ask, and you do not have to guess from the size. If a download says nothing, it is current.

Updating is incremental. Every file is checked before it is fetched, so an update pulls only what is new and skips everything already on the phone. It updates that download in place rather than making a second copy, so the same button is also how you resume one that was interrupted.

The check is skipped when you are offline, and when the connection is one the app judges too weak to spend on — a trailhead with one bar is exactly when you do not want the app pulling records to answer a question you did not ask. In those cases nothing is shown rather than a wrong answer.

Managing space

The On this device section lists every download you have, the networks it covers, and its size, with a Remove button on each.

Before a download runs, the total is checked against the space actually free on your device. If it would not fit you get a clear warning, plus a note naming the single biggest category so you know what to turn down first — usually photos set to All.

Two storage behaviors worth knowing:

• Records, photos and base-map tiles are stored as app data. They stay until you remove the download or delete the app. Nothing the phone does on its own can take them.
• Contours and slope shading are stored in the browser's cache, which iOS and Android are allowed to reclaim when the device runs short of space. It is not common, but on a nearly-full phone terrain shading can go missing while everything else survives.

Base-map tiles used to sit in that second group, and moved. It matters because of how the loss showed up: the map itself would quietly go back to a plain background, and the download would offer an update whose file count matched the tiles exactly — which read as your download is out of date when the truth was your phone reclaimed the space. Tiles are now real files in app storage, like your photos, so a download keeps its map.

The storage screen itself

The download sheet is one part of a bigger screen. Storage in the menu accounts for the whole app: what your queued uploads are holding, the photo and map-tile caches the app fills as you use it, the app itself, and the total your phone reports.

Two buttons at the bottom of it clear things, and they are not interchangeable.

Free up iOS storage, which reads Free up Android storage on an Android phone, drops the hidden system cache: the copies the phone keeps of things the app has already loaded. That is what iOS counts under Documents & Data and Android counts as cached data, it is invisible from inside the app, and it is why an app can look far bigger than the data in it. Your downloads, your queued uploads and your login are untouched, and the app refills it as you work. After an app update this now runs on its own, because a new version turns the previous version's copies into dead weight; the button is there for the times in between.

Clear cached photos, tiles & shell is the heavier one, and it asks before it runs. It clears what the app cached as you browsed — and because they share the same store, the contours and slope shading from your downloads go with it. Everything else in a download survives: trails, tasks, the photos and the base-map tiles are app data. Pending uploads survive and you stay logged in. The app rebuilds the rest from the network as you use it, so it is not a thing to do on the way out of signal.

On older app builds that button cleared downloaded terrain and the app shell as well. Where that is still the case the app says so before it runs, and the next app update settles it.

That is why the sheet has a way to check.

Checking a download

Tap Check downloaded terrain in the download sheet. It reports one of:

• Nothing downloaded — no terrain in any download on this device. Three things cause that, and only two are fixed by downloading again: the download ran before terrain existed for the area, the category was switched off when it ran, or the terrain there still needs regenerating. The terrain row in the download sheet says which.
• Downloaded and readable — everything is fine.
• One of three more specific faults, each with a different fix: files recorded but not addressable, files present but unreadable, or files readable as images but blocked for the map.

The distinction matters because "the shading isn't showing" has several causes that look identical on the map. If you are about to report a problem with offline terrain, run this first and quote what it says — it turns a guess into a diagnosis.

If it reports fewer files than the download sheet quoted, that is the storage reclamation described above. Re-download to restore them.

The same button reports the base map separately, because the two fail independently: terrain can be perfect while the base map has been reclaimed, and one verdict covering both would have to be wrong about one of them. It reads back a real tile at the deepest zoom you downloaded — a shallow tile covers a whole region and would pass while everything at the zoom you actually navigate at was missing.

Common gotchas

• Downloading is per device. Two phones need two downloads.
• Base map tiles are only in a download on the TrailsIQ map. On a Mapbox-backed organization, pan around the area while you have signal so the tiles you need are cached, and expect a plain background beyond that.
• Routes you walked in the planner come too. A download covers your trails and, on the TrailsIQ map, any planned route somebody recorded on foot — up to the 25 most recent. That is the case this exists for: you scout a line in country with no trail yet, and without it the download would have had nothing to offer for that ground. Routes that were drawn or suggested rather than walked are not included; they may never be built, and a proposal is not somewhere anyone is about to stand.
• Base map tiles are shared between downloads. They are public geography, identical for everyone, so two downloads over neighboring ground store one copy — the second costs almost nothing. Removing one download never takes a tile the other still needs.
• Photos in a download are downscaled. They are sized for reading a task in the field, not for zooming into a crack. Opening a photo full-screen offline shows the downloaded copy; the original needs a connection.
• "All" on tasks and photos is where the megabytes are. On an established network the resolved-task history dwarfs everything else. Open only is the right default for a work day.
• Terrain has to have been generated for your area. If the category says Nothing baked for this area yet, there is nothing to download — the elevation tiles are produced from your trail lines, so a network with no trails on it has no terrain either.
• Terrain you can SEE on the map is not always terrain you can download. If the category says the tiles were baked from the old source, the contours and shading over that ground were generated before TrailsIQ moved to open elevation data. They still draw normally, and they are deliberately kept out of downloads, because a download is a copy we hand you and the older data was not ours to redistribute. This is the one case where re-downloading changes nothing at all — the same files are excluded every time. It clears when that area is regenerated; ask us and we will run it.
• A download does not freeze your data. Live data always wins when you have signal; the download only fills gaps.
• No "new files" line means no news, not "not checked" — unless you are offline or on a very weak connection, where the check is skipped deliberately. Open the sheet somewhere with signal before a trip if you want a definite answer.