WHERE YOU ARE
Hold still — a first GPS fix can take a few minutes.
Emergency numbers normally connect from any phone that can see a network, including one with no SIM or no credit. They do not work with no network at all.
Your position keeps working when your phone has no signal. GPS listens to satellites; it needs no reception and no data. What it does need is sky — step out of the vehicle, away from cliffs and trees, and wait. Without a network to help it along, a cold fix takes one to five minutes.
If the readout above never leaves “Looking…”, the browser is refusing to ask
for your position. On Android there are three separate causes. Tapping the file in
Downloads or Files opens it at a content:// address, which is never given
GPS — open it from a folder so the address starts with file:///. Chrome
itself needs location permission from the phone: Settings › Apps › Chrome
› Permissions › Location. And the phone’s own Location switch, in Quick
Settings, has to be on. On an iPhone there are two switches, both required:
Settings › Privacy & Security › Location Services › Safari Websites
and Settings › Safari › Location.
The fallback works whatever the browser decides: press and hold the map where you are, or type coordinates into the search box, and this screen will read them back in large type. Check which of the two you have before you need it.
This app has no routing and no hospitals or police stations in it. Install a full offline map — Organic Maps or OsmAnd, with the Japan region downloaded — before you fly, and keep a paper note of where you are staying.
Add your own point. Move the map so the cross sits on the spot, or tap where it is. You can also paste coordinates on the next screen.
車中泊 (shachūhaku) means sleeping in your vehicle. It is ordinary and widely accepted in Japan, and it is the cheapest way to drive the country. It stays accepted because the people doing it are quiet, leave nothing behind, and do not treat a car park as a campsite.
Tap the pin with a plus on the map to add a place that isn’t in here — a trailhead, a shuttle stop, anything. They join the same list as everything else, in the colour of the type you pick, and start out starred — un-star one and it becomes an ordinary dot, still there to edit or delete.
Points you add live in this browser on this phone. Points that came built into the file are there for anyone who opens it. To keep yours safe, or to send them on to be built in, export them.
Wash at the taps and rinse off completely before getting into the water — the bath is for soaking, not cleaning. No swimwear. Take the small towel in with you and leave the big one in the changing room. Tie up long hair. Tattoos are still refused at some places, so check at the desk if it matters.
This page is the whole app, and there are two ways to keep it. They are not the same thing. Do one of them before you leave, not at the roadside.
Put it on the home screen. It then opens full screen like an app and works with the SIM dead, because the browser holds its own copy of the whole file. In Safari that is under Share; in Chrome, the ⋮ menu.
Download the file. Then you have the thing itself: one file you can keep in Files, copy to a laptop, or send to whoever else is driving. It outlives the home-screen copy, which goes when the cache is cleared, when the browser decides it needs the room, or when the phone does.
Download the fileEverything is in this one file — map, spots and text. It needs no network, so it works in a tunnel, in the mountains and on a dead SIM. The only buttons that reach for one are the ones labelled as such.
The layers button is the exception worth knowing about. It steps through the offline map, road tiles and satellite imagery; the last two are fetched as you look at them, so they cost data and they need signal. The offline map is always drawn underneath them, which means a tile that does not arrive leaves the plain map showing through rather than a hole, and with no signal at all you get exactly what you would have got anyway. It says so once, then stops asking for a minute rather than draining the battery on retries, and picks up again by itself when you are back in range. Your choice is remembered, so leaving it on satellite costs nothing until there is a network to spend.
Every town, city, ward and prefecture in Japan is in here as well — about two thousand of them — so you can type where you are heading and the map will go there with no signal involved. Names answer in English or Japanese, with or without the administrative suffix: matsumoto, Matsumoto-shi, 松本 and 松本市 all find the same city. Going to a town also re-measures the list around it, so what you are reading is what is near where you are going rather than what is near where you are now; moving the map yourself hands the list back.
Zoom runs in until the scale bar reads 20 m, close enough to pick out an entrance or a parking bay on the imagery. The offline map cannot follow it that far — its coastline is simplified and it holds no roads — so if you zoom past what it can draw and nothing else is on screen, it tells you rather than leaving you looking at a blank field.
Spots come from OpenStreetMap and are used here under the Open Database Licence. Names are shown in English where OpenStreetMap has one; otherwise they are romanised from the Japanese reading, and where there is no reading to work from the Japanese is kept as-is. The Japanese name is always shown too, because that is what is on the sign and what you can point at when asking directions. Coastlines and prefecture outlines are from Natural Earth, which is public domain.
The shaded parks are national, quasi-national and prefectural natural parks from the 国土数値情報 (National Land Numerical Information) survey published by Japan’s Ministry of Land, Infrastructure, Transport and Tourism, used here under its attribution and non-commercial terms. The survey is the 2010 edition, so parks designated since — Kerama Islands, Yanbaru, Amami Gunto — are not in it. Park names in English come from Wikidata (CC0), matched to each boundary by position; where no match was found the park is drawn without a label rather than guessed at.
The towns and cities come from Wikidata too, keyed on the 団体コード every Japanese local government carries, with the area of each one deciding how far the map zooms in when you go there.
Opening hours, fees and facilities are whatever OpenStreetMap recorded, which may be out of date or missing entirely. A blank field means nobody has mapped it, not that the thing is absent. Treat it all as a starting point and trust the sign in front of you over this app.