Atlas wrote:
snip
Great link. It looks like there's a lot of details there in those
vectors.... I've found some S57 med maps and I had a go just to "try before
you buy" and the detail is zero!!! Storing vector data is nothing difficult
nowadays, and computational power is fair enough to recalculate and redraw a
chart. The maps you've pointed out show exactly that it is possible to store
enough data into vector based products like if they were rasters.

On the U.S. S-57 charts I think all the same details are there, at least
on the water anyway, on both the vector and raster charts. On the
adjacent land areas the prominent features that a boater might use are
there too (towers, smokestacks, etc.). But there is little or no detail
of streets, topography, and the like.

And the presentation of the details in the navigable water areas on the
S-57 charts has very subtle shadings in the way it depicts markings for
everything from navaids to piers,pilings, awash rocks, and the other
stuff. When I look at a NOAA BSB4 raster chart (or the Navionics
charts) the details sort of leap out at me in comparison.

It may be that I am an old dog and not doing well with new tricks, but I
really prefer looking at the details on the BSB4 raster over the the
S-57 vector charts. I hope the raster charts are not discontinued any
time in the near future, I'll miss them.

I'll try to download some of thos NOAA S57 maps to get an idea.

Thanks for your precious thoughts

You're welcome of course. Here are two charts (and the starting point
for download links) that are good examples to show you the difference
between a NOAA BSB4 and NOAA S-57 chart for the inner harbor area of
Portland, Maine, USA.

S-57 VECTOR:
US5ME10M - PORTLAND HARBOR AND VICINITY, ME - 1:20,000

http://nauticalcharts.noaa.gov/mcd/enc/index.htm

BSB4 RASTER:
13292 - PORTLAND HARBOR AND VICINITY, ME - 1:20,000

http://nauticalcharts.noaa.gov/mcd/Raster/index.htm

If you can download those through Coastal Explorer it is a little
simpler than using the NOAA map server links above. If the map server
seems unnecessarily complicated, bear in mind that it is part of a
government bureaucracy. And free. :)

NOAA uses the term ENC (Electronic Navigation Chart) for referring to
the S-57 series charts most of the time. The S-57 charts arose from the
IHO international agreement and all the participating nations agreed to
the format, details, etc., and are all supposed to be working towards
producing those charts.

Jack