The default layer on this map is created from OpenStreetMap data. It’s designed to show information that’s specifically useful to rural pedestrians - things like public footpaths and bridleways, and which roads you can safely walk along because there’s a roadside pavement or verge. There’s a map legend here, but it’s quite large, so you’ll need to scroll around to see it all, and also zoom in to see things that are only visible when you are zoomed in. Recent changes that have been made to what is shown on the map can be seen here.
Other map layers contain data from other sources - for example the “Flooding” layer contains Environment Agency data.
It handles a much larger proportion of the tags used in OSM than other maps. It groups similar objects together, so for example “shop=vehicle” will appear with the same icon as “shop=car”. It does this via osm2pgsql and lua to customise the database for rendering, making queries easy to write.
It uses a wider variety of icons than other maps, especially icons with a small modifier indicating a certain feature, such as a shop that sells zero-waste products.
It shows features not normally shown on general-purpose map tiles, such as England and Wales rights of way and hiking and cycling routes.
It uses geographical customisation so that (for example) a Welsh name will be shown in Welsh-speaking parts of Wales and an English name in English-speaking parts.
Yes, you’re welcome to link to it. As you zoom in the URL changes, so the contents of the URL bar should always link to what you are seeing.
The map is actually composed of a series of map tiles, such as this one. You can add these tiles as a layer to another map, provided that you link back to the map style somehow (e.g. by linking to this page) and credit OpenStreetMap on the map layer as described here.
What you are not allowed to do is any sort of bulk downloading (i.e. downloading more than you need to display on screen at once).
This data that this map uses is all added by contributors to the OpenStreetMap project . In some areas it’ll be significantly better than commercial or governmental alternatives, but in other places (with fewer OSM contributors) it won’t be as good. As with all maps, it may contain errors - because of that please don’t infer that you have a legal right to do anything or go anywhere based on information shown on this map. In particular, the “No vis paths” layer includes things that might be “a way to get up a mountain” but may not be an obvious “path”. Also note that a particular route (e.g. here) may be safe to travel along at some times but not others (e.g. when a river is in spate), or only with suitable equipment. Your safety and that of those with you is your responsibility.
Apart from the places shown at very low zoom levels, the data that this map uses is updated from OpenStreetMap data every few minutes. Depending on what you’re looking at, changes will either appear very nearly immediately (when you’re zoomed in) or in a few days (zoomed out). Nothing should be more than about 4 days old, though you may see cached tiles (either in your browser or from the server, while a new tile is being created).
You can update the data that this map uses by going to https://www.openstreetmap.org/ and following the advice on this page.
You can, but only by creating your version of the map using your own map tiles. The changelog contains some links at the top to the various parts of the map style in github - create an issue there if you’ve got further questions.
I am the only person that I’ve set up to have access to this server (tiles loaded from other servers are accessed by other people, of course). If you request tiles then the normal Linux logs will record the fact (Apache’s “access” log stores which IP address asked for a tile when, and the “syslog” stores details about new tiles being rendered). The logs store data for about a week and then wrap around. I can’t comment on who might be watching traffic between you and the server (in Finland). If you’re particularly worried about people NOT knowing that you’re requesting certain map tiles I recommend that you set up your own server and serve tiles from there instead.