Limitations
- Map line drawing is slow when there are many tracks (over 200 or so). This is due to underlying performance issues in the MarbleMap's geo-line drawing, which is not using OpenGL. The best fix for this would be in Marble, but I will try to investigate the idea of overlaying a custom OpenGL widget on the map. If that pans out, it may be a viable workaround. In the meantime, you can hide some of the tracks to improve map drawing performance.
- The Map Display tab in the configuration settings also has an "Interactive Movement Behavior" section. You can set this to display only the active track during movement, which helps interactive performance.
- Only Garmin GPS devices are supported with direct device import, and only those which support GPX, TCX, or FIT export. Other devices can use the file import facility.
- There's no support for zip-compressed import formats.
- There is no way to enable map overlays, such as for hillshading layers.
Known Bugs
- KML exporter is not smart about measured vs. computed power.
- Control+drag over a map has troubles drawing the selection rubber-band: it doesn't always erase its old position. The reason for this is technical, due to an awkwardness in libmarblewidget-qt5.so: see comment around trackmap.h:102