I believe, that you missunderstand me. The datas you mean are the 50 m grid datas. With 50 m distanz between data points you can't get correct results in norwegian waters, in the much flatter baltic sea is this also only limitid possible.
But i mean the ready shape files (with 5m, 10m, 20m, 30m, 40m, 50m, 100m, 150m ... lines/areas/deep points, flood aeras etc.). This is about the same material, as for the Navionics/Garmin... charts und i believe, this is good material for an overview/fishing spots. The job for me is create new overlay maps with my own datas, but as background i only use the official datas.