"Wayne.B" wrote in message
...
On Mon, 18 Sep 2006 07:45:00 -0400, "Gerald"
wrote:

I am convinced that raster charts are the way to go and that, perhaps, I
am not in the mainstream and have made it to the position of 'old-fart'.

I hear you, vector charts definitely takes some getting used to, and
for some things raster is clearly superior.

For the last two years I've had both side by side, raster on
PC/Maptech, and CMAP/vector on a Furuno chart plotter. I agree with
much of what you say, but have come to appreciate some of the benefits
of vector as well.

I have never actually used vector charts underway. Marine vector only in
showrooms and boatshows. Like it or not, I suspect I am going to have to
make the leap -- grumbeling all the way, but doing it. I am in the process
of downsizing and won't have the room or 'trons to do what I am used to.

One thing that vector does much better is "zoom in" and "zoom out".
When you zoom a raster chart the text fonts and pixel details get
larger and smaller also, which renders them illegible very quickly.

Again, something I will have to 'learn to love'.

Vector on the other hand automatically compensates for zoom level so
that font sizes are constant, and detail pixels are adjusted to an
appropriate size. The net result is that fewer vector charts are
required for any given area since detail improves as you zoom in,
unlike raster which requires an entirely new chart to show greater
detail.

Logically that should be the case. The examples that I have seem in demo
machines don't have much of the detail I am used to seeing to begin with, so
the zooming effect doesn't matter --- the details ain't there. It may well
turn out that that is more a function of the demo, demo operator or
excessive nit picking on my part. In the long run, if it isn't totally true
now, it will be someday.


The other area where vector is clearly superior, is "course up" mode.
Course-up is a much more intuitve way to view chart data, particularly
in close quarters. However, if you display raster charts "course up"
on anything other than a north bound heading, chart text and symbols
appear rotated out of the normal vertical orientation, and are
actually upside down in south bound directions. With raster charts,
the text and symbols are automatically rotated to stay in normal
orientation, making course-up much more useful.

This is one of those interesting areas that make vector a selling point for
some, but not me. Having done paper charts (read north up) for so long, it
is natural for me. I have tied using my Maptech in course up and found it
disorienting. My minds eye sees the world in a north-up orientation,
looking at something in a heading up orientation feels, well, just wrong.
No, I didn't give it a real chance. I tried it for half an hour ro so here
and there, pronounce the foolishness of it all, and go back to north up.
There are some paper charts strips in the Chartbooks that are turned to
other than north up to optimize printing, I turn the North up too (chart
book cockeyed). Ok, I have found the problem: I AM and old fart!!!!!!


On our boat I generally do all of my route planning on the PC using
raster charts since Maptech is very good at that, and I can do
everything off-line in the comfort of the main cabin the night before.
While running I keep the PC zoomed out to show the big picture and the
route information such as range/bearing to next waypoint, total miles,
time-to-go, etc. On longer legs I will transfer the next waypoint
details to the Furuno chart plotter as well. The chart plotter is
usually left in course-up mode and zoomed in to a fairly high level of
detail where chart symbols are resonably uncluttered and easily
readable.

I had a similar drill. After I loaded (or selected) my route in Maptech, I
would export the Waypoints into my GPS system. If the computer crapped out,
everything was ready to go on the GPS. This was especially useful when
offshore. I had the autopilot set up to take steering commands from either
the computer or the GPS. Again, if the computer died, I would not actually
have to steer the boat - heaven forbid!


Another superior feature of the chart plotter, unrelated to
vector/raster, is screen brightness and clarity. The brightness level
is fully adjustable for comfortable viewing all the way from direct
sunlight to complete darkness. No PC or flat panel display that I
have used has a comparable level of brightness or adjustability.

I had high brightness OceanPc displays in a pilot house environment, so this
was not a problem. It will be an issue in the new boat: no pilot house.


With the right selection of features and options, the chart plotter
has some other worthwhile attributes. For example our Furuno system
has the ability to super impose radar data on top of the chart display
which is very useful for identifying unkown radar blips and determinig
whether or not it is a navaid or probable boat. Since this feature
requires rotating and zooming the chart data to match the radar
display, vector charts are clearly the right choice.

While all of this has been available in the PC / Raster chart arena,
certainly not a cost that compares well with the integrated solutions
available with vector charts. This is a great feature and I look forward to
playing with it. I suspect this really requires the use of a gyro compass
to get a sufficiently stabilized overlay. I had a gyro on my last boat and
it made a big difference in ARPA accuracy.

I hope I have that whine out of my system so I can just get on with it...