Hi, it would be nice to have the possibilty to show the openseamap map as a layer.
OpenSeaMap uses OSM Mapnik as a base layer and then adds various controllable POI type layers on top, see http://wiki.openstreetmap.org/wiki/OpenSeaMap
Viking *only* displays static image tiles plus your own GPS derived data.
Any mechanism to display extra remote POIs is not going to be added soon by any of the active code contributors.
Note Viking can use any remote tile server see:
I found that OpenSeaMap provides a bitmap overlay.
You can add such feature by adding the following lines to ~/.viking/maps.xml
Then, you can add an "OpenSeaMap" layer. Here is a .vik exemple mixing OpenSeaMap and OpenStreetMap (Note that OpenSeaMap only provide high detailed zoom levels):
#VIKING GPS Data file http://viking.sf.net/
OpenSeaMap added as source in file maps.xml shipped with viking.
Bonus that you found some pre rendered Open Sea Map tiles!
However you should be aware that the internal maps id is currently defined as a guint8 type
Thus ATM we're limit ourselves to 'only' 256 map ids, so id 600 actually wraps around - probably to id 88.