[ Thanks to Dmitri
Popov for this link. ]
“To perform its magic, digiKam relies on the KML Export plugin.
If you don’t see the Export to KML command in the Export menu, then
you have to enable the plugin. To do this, choose Settings →
Configure digiKam, switch to the Kipi Plugins section, enable the
KMLExport plugin, and press OK. Select then the photos you want to
export, and choose the Export → Export to KML command to open
the KML Export dialog window. In the Target Type section, select
Google Earth or Google Maps as the target…”