"don" wrote in message
...
Bruce in Alaska wrote:
In article ,
"Doug Dotson" dougdotson@NOSPAMcablespeedNOSPAMcom wrote:


The digital charts are made from the paper charts.


Actually, all US charts, paper, or digital, are produced
from a common NOAA Digital Database. This database is
available for purchase, by anyone, for a price. (Very High)
The database is always being updated, with new, and or revised
data, but is archived at fixed intervals, for distribution
to the Official NOAA Printers and Digital Chart Providers.
Archival Dates are published with the charts, so that one knows just
when the dataset was frozen for that publication.


Bruce in alaska
One of the reasons for asking is that in our area on Lake Buchanan a
Navonics boat was out there plotting contours. That got me to thinking
that maybe their maps might be unique with some other value add over the
paper and other standard maps.

I'm familiar with all the scanning etc. I've done a bit of that myself
using Fugawi to scan paper in and then calibrate and then download to my
PDA with gps attachment. Unfortunately, I can't do it on my LMS320.

don
Navionics has a map series for inland lakes for fishermen to use with fine
bottom contour information way beyond what is available from the government.
I have been told they started in the eastern USA and are slowly working
their way west. yes, they are doing their own detailed survey.
73
Doug K7ABX