Rich Hampel wrote:
... OVERMAGNIFICATION will result in some
pretty strange errors of 'resolution'.
....

I've not used the ENC charts but am very familiar with C-Map and
Transis vector charts. Over magnification with these systems produces
an image rendered with noticeable polygons. All of the chart rendering
programs I've used display warnings when over zoomed and some also
refuse to render over magnified charts. Anyway, I don't recall any
'strange errors of resolution.

One must remember that the 'basis' of many of the charts were leadline,
pelorous, etc. and to simply OVERMAGNIFY them can get you into serious
trouble real fast as the overmagnification is easy .... and very
foolish. ...

It would be nice if all the notes and diagrams that appear on paper
charts were always reproduced on the digital versions. If you are
looking at a chart that is based on a 19th century survey and has a
diagram of soundings that is mostly white then you are well advised to
keep a particularly good watch. I'm not sure that these kinds of
problems are more acute with digital media than with paper. However,
the digital chart error that I see getting most people into trouble is
using a non wgs correctable digital chart with a gps and has nothing to
do with magnification. Could you be more specific about the trouble
you have seen that has been caused by over magnification of vector
charts?

-- Tom.