Download Maps
Download maps before your trip so you can use them without a connection. Choose a whole area or select grid squares to save just the places you need.
Open the round three-line menu button at the bottom right of the map screen, then choose Map Management.
Choose the area and map type
In My Areas, expand the area you want to download, then find a map type such as OS 1:25,000 or OS 1:50,000. Each map type is downloaded separately.
For a trip across Scotland, use Great Britain. If your list only shows National Parks, add Great Britain:
- Select Add Area in the Maps section.
- Choose Countries in Group, then Great Britain in Area.
- Select Add, then expand Great Britain in My Areas.
Adding an area lists its maps; it does not download them. Areas already in My Areas are not offered again in Add Area.
Check that your device has enough free storage. On iPhone and Android, Settings > Data controls whether downloads can use Wi-Fi, cellular data, or neither.
Download a whole map
Open the map type's three-dot menu at the right-hand end of its row, then choose Download All. On desktop, you can also select the row and use Download All in the toolbar above the map.
This downloads that map type throughout the chosen area. For example, Download All under Peak District covers the park; under Great Britain it covers the available mapping across Great Britain.
Download part of a map
- Find your map type under My Areas, open the three-dot menu at the right-hand end of its row, then choose Download part of this map.... If all its mapping is already downloaded, this action is called Select mapping instead. On desktop, clicking the row also shows the selection map beside the list.
- Zoom out until you can see your destination and the grid squares. Scroll the mouse wheel backwards on desktop, or pinch two fingers together on mobile. Drag to move the map.
- To bring the map's whole available area into view, use the button with two diagonal arrows pointing apart. On mobile, it is the blue round button near the top left, below the Select Mapping heading. On desktop, it is in the toolbar above the map, after Exit. This button is called Fit to coverage. You can then zoom in on the places you need.
- Click or tap grid squares to select them. Selected squares have purple shading. Select a square again to remove it. Zoom out to select larger blocks, or in for a finer boundary.
- Choose Download Selected, checking the size shown. On desktop, it is in the toolbar above the map. On mobile, open the round three-line menu at the bottom right of the map to find it.
Use Clear, in the same menu or toolbar, to remove your selection and start again. On mobile, the back arrow at the top left returns to My Areas.
Download height data
Height readings and terrain elevation profiles use separate Height Data. Downloading an OS map does not download its height data, but OMN4 can now fetch height data as you need it online.
- On desktop, pause the pointer over the map to let OMN4 fetch the height for that position when streaming is allowed.
- When you open a route or track Profile, or its terrain statistics, OMN4 automatically fetches missing height data if it is less than 50 MB and streaming is allowed.
- For larger requests, or when automatic streaming is unavailable, the view shows how much height data is required and offers Download Now. This follows Map Download, rather than Map Streaming, in Settings > Data. Progress and Cancel are shown while fetching.
- If part of the route is outside height-data coverage, OMN4 explains that height data is unavailable for all of it. Downloading again cannot add coverage that is not supplied.
For dependable offline use, open Map Management, expand your area under My Areas, then find Height Data. Choose Download All, or select the coverage you need and use Download Selected as described above. Let the download finish before leaving your connection. Choose the height coverage on each device you take with you; streamed data is held in a cache and is not a planned offline download.
If heights remain missing, check your connection, data settings and coverage. On an older OMN4 version without height streaming, download Height Data through Map Management or update OMN4.
If the selection map looks bright green
Map Management shades already downloaded, current mapping green. At a close zoom level, this shading can fill the screen. Zoom out, or use Fit to coverage, to see its boundary and the surrounding area.
If the action says Delete Selected when you want to download more mapping, use Clear, then start your new selection on a square that is not already fully downloaded.
See What the colours mean for the full colour key.
What to expect after you queue a download
- The queue bar at the top shows the total queued size.
- A queued item shows a dot in the list.
- Active work shows a spinner or a remaining size such as
1.2 GB left. - Very large downloads can take time to prepare before downloading starts.
When the download completes, the saved coverage is shaded green and the stored size increases. The map row shows Partial on device if you downloaded part of the area, or On device if you downloaded it all. Let downloads finish before you leave.
After your trip, you can remove downloaded map data to free up space.
If the action says update instead of download
If a row shows Partial Outdated or Downloaded Outdated, OMN4 has older downloaded data for that map.
In that case you may see:
- Update All — updates the outdated downloaded map data without downloading any more.
- Update & Download All — updates the outdated tiles and downloads the remaining map data.
If downloads do not start
Check these first:
- On mobile, Settings > Data > Map Download may be set to Disabled.
- If Map Download is set to WiFi Only, queued downloads may wait until Wi-Fi is available.
- If another map operation is already running, OMN4 may make you wait for that to finish.
If OMN4 is waiting for Wi-Fi in Map Management, the panel can show Waiting for WiFi... while queued downloads remain pending.