A point on OSMaps (or otherwise)

OS Maps stopped working on my phone in Scotland on Saturday. This led to a bit of cross-checking, and it might be worth sharing our thoughts. (With apologies to those who already know all this stuff. -- or who may offer technical corrections). .

The maps on the phone come as data via internet connection or phone signal. The little red arrow telling you where you are, comes (we think) firstly from telephony and then from satellite. It turns out that Android phones (mostly) do not connect to satellite, and on iphones not before i14 in 2022, according to https://www.androidpolice.com/wait-for-android-phones-satellite-connectivity-got-longer/#:~:text=Summary,partnership%20has%20been%20called%20off.

So in long and lonely Gen Mark, where there is no telephone signal for some miles, the little red arrow just froze and was useless. It seems that you can mimic a lack of signal by switching aeroplane mode or switching off mobile data; and then check if OS Maps still works, thus testing whether a particular phone connects to satellite or not. Basically no Android, and i14 or later)

Another wise move before going to more remote areas which may not have telephone signal, is to make sure the phone has an offline map downloaded. A test showed that even if your phone is satellite-enabled, when you go beyond the edge of whatever was previously downloaded (and when there is no data connection) then you get a little red arrow in the middle of a white screen. An accurate image, maybe, in dense fog or white-out, but no longer an aid to navigation.

Obviously a satellite GPS device does not encounter such problems. Mine has all-UK 1:50K maps on an SD card. BUT battery lefe may be an issue, and if you play with it all day long then have a problem at dusk, it might close down just when really needed. If the device produces a Grid Reference, it's worth bearing in mind that GR does NOT indicate a position. A six-figure GR denotes an area 100m x 100 m which is 2.4 acres, roughly enough land to build 30 semi-detached houses.
An eight-figure grid reference implies reading the map to an accuracy of 0.2mm (50K) or 0.4mm (25K) and on a windy rainy mountainside...................

So it seems worth knowing when these handy little gizmos might not always perform. And of course the standard doctrine remains always in the mountains to have a map and compass and know how to use them


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