I am new to GIS and QGIS, and really lost with some basic QGIS concepts.

I have installed the GarminCustomMaps plugin, and by usign the default plug-in settings I am able to generate a single tile of the area that is visible on the screen in QGIS.

What I'd like to do instead is generate a KMZ file that contains multiple tiles covering an area I select in QGIS.

My source in QGIS is a WMTS layer from the French geoportail site: https://wxs.ign.fr/<access key>/geoportail/wmts?SERVICE%3DWMTS%26REQUEST%3DGetCapabilities The source is multi-resolution - as I zoom in I get different sets of images.

Here are some questions I couldn't figure out: - what is the zoom factor of the plugin used for exactly? If I use anything by the default value of 1.0, I end up with a blank KMZ file (checking in Basecamp) - The plug-in seems to export whatever is visible on the screen. If I make a larger area visible, the layer switches to lower scale maps (e.g. 1/50,000 instead of 1/25,000): is there any way to display a larger area without the scale changing?

  • Is there any way to define an arbitrary extent to be exported by the plug-in?

I am probably not using the right terminology, but I have gone through all the documentation I could find and I am still pretty confused.


The reason why you get only white tiles is most likely that the maximum tile size of your WMS is exceeded when the map is rendered with increased resolution.

What you could do is download your WMS e.g. through GRASS r.in.wms in desired resolution or use GDAL / gdal_translate for that... Then you can load the resulting raster map in QGIS and the GarminCustomMap plugin will do the tiling for you...

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I tried out that GarminCustomMaps extension and then studied the "Garmin Custom Maps" format. The extension is not flexible. First I considered improving it, but then realized that the Garmin format itself is so limited that it's not worth the effort

If you have a supported Garmin device, you might want to consider working with the JNX (Birdseye) format instead. The downside of this is that you will have to patch and install firmware on your device to get around the Garmin encryption scheme.

More details of the pros and cons are here, as are more details on software: http://whiter.brinkster.net/en/JNX.shtml

I am trying to figure out how to use QMapShack now, it's supposed to be able to read and write JNX files.

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