Offline custom OpenStreetMap layer or map view [JOSM] [Export]


I would like to create a custom OpenStreetMap map section that I can use offline and do not need to submit to OpenStreetMap.
I work as a volunteer with my colleagues in a larger forest and there are many forest trails and roads that we use, but we wouldn’t like to share these with the public because they pass through highly protected areas. Therefore, I don’t want to upload them to OpenStreetMap.
Unfortunately, we don’t yet understand the technical aspects of map editing, but we would like to create a layer (map view) like the bicycle routes in OpenStreetMap, so that the display can be turned on and off over an earlier map, like a layer view.

I tried the JOSM application, the roads we want to record can be easily edited with it, but I could not export the end result in any known format that could be handled by offline Android navigator applications (e.g., Oruxmaps, Locus, Garmin GPS) [file format maybe: sqlite, kmz, etc.].
True, it can be exported to gpx, but every program handles it as a gpx-track, which is confusing and unmanageable, not as a map layer/view.
Btw, we use Locus.

Could you help with how we could create a custom map section that could then be exported to (for example) Locus?

Thank you very much!


There is a plugin for osmosis that allows to create maps in the mapsforge format for use with Locus and Orux.

For Garmin devices, there is mkmap which allows to create a map or overlay in the Garmin IMG format. This is a bit tricky as you have to create a mkgmap style and a corresponding Garmin TYP file for the ways you want to display. With the mkgmap style you instruct mkgmap to assign a Garmin object id to the OSM objects you are interested in. With the TYP file you define how the Garmin device displays objects depending on their id. An editor like TYPViewer is needed to create or modify TYP files.

To generalise a bit, any application that works with maps that you can create from OSM xml or pbf data should work.

Using Josm (or anything else) you can create some “osm-like” data but not upload it. Just make sure that the node, way and relation ids are beyond the range used by OSM data.

Then, using something like “osmium” you can merge it together and then create a .pbf file that “mkgmap” or “osmandmapcreator” or whatever can read.

If your app wants to scrape tiles from somewhere then you can create a local webserver using the switch2osm guides, and load your combined data in.

If you’re happy with OsmAnd as your map application you can use JOSM etc. to create the data without uploading it and then OsmAndMapCreator to create a maps file that you can sideload onto your devices.