Qt/Qml: how to include map tiles for offline usage?

Question

I need to include offline tiles (slippy map) into a Qt/Qml mobile application that mainly runs on Android and iOS.

The only well-documented and working solution I found

Answer 1

I know this answer is late, but I had the same challenge with client supplied offline maps on Linux

You need to create the directory structure for your map tiles. As I used openstreetmaps I copied the directory structure that they use i.e. root/zoom_level/area_level_1/area_level_2/tile.png

e.g. :

~/osmTiles/12/3820/2078.png

I used marble (https://marble.kde.org/install.php?) to download the map tiles into the correct directory tree (cached), which I then copied to the target hardware and replaced the osm tiles with the client's .png files

I then used npm from node.js to install http-server and hosted the root tile directory as an http server at http//localhost:port (this answer explained it very well: https://stackoverflow.com/a/12905427/5452614)

e.g. :

http-server ~/osmTiles -p 8080

which served osmTiles on http//127.0.0.1:8080

finally I modified the standard QML Plugin thusly

Plugin {
  id: osmPlugin
  name: "osm"
  PluginParameter { name: "osm.useragent";         value: "My Company Name" }
  PluginParameter { name: "osm.mapping.host";      value: "http://127.0.0.1:8080/" }
  PluginParameter { name: "osm.mapping.copyright"; value: "MyCompany" }
}

where I told QML where to look for my offline tiles. I had to specify that the map should be a custom map, which was harder. Through trial and error I found that supportedMapTypes[7] is custom map. I don't know why, but that's just how it worked out

Map{
  plugin: osmPlugin
  activeMapType: supportedMapTypes[7]
}

Answer 2

Using offline maptiles is now possible through the ArcGIS Runtime library, starting from version 10.2.6:

https://developers.arcgis.com/qt/qml/api-reference/class_tiled_map_service_layer.html

Answer 3

@Marco Piccolino, following our conversation from this other thread, here's the detailed workaround I've found so far, using only QtLocation, an offline tile cache, and a simple http server:

• You need to place your png tiles into a folder tree like this: ".../tiles/1.0.0/sat/{z}/{x}/{y}.png", cf this link

• You have to run an http server on that folder (you might want to use this command: sudo python -m SimpleHTTPServer 80)

• You will have to edit your hosts file to map the following domain to your server's IP address (most probably 127.0.0.1): otile1.mqcdn.com. This trick is quite dirty but as this url is hardcoded inside the QtLocation OSM plugin we don't really have much of a choice with the current available QML API.

• Finally the easiest part, in the QML code you should have something like this:

Plugin {
    id: mapProvider
    name: "osm"
}


Map {
    anchors.fill: parent
    plugin: mapProvider
    gesture.enabled: true
    activeMapType: supportedMapTypes[1]
}