[bobetter]

I guess this is a case of having the map adjust to reality automatically instead of having to take steps such as advancing to the next waypoint manually or even to move the WP... I don't want to interact with the computer more than necessary while I'm busy sailing, I just want it to follow and adjust to reality in a (to me) intelligent manner so I can glance quickly at the display and not get crazy readings like when it's still trying to bring me to a waypoint that we passed half an hour ago, but happened to pass the WP just a little bit too far away because we tacked a bit off route...

If the chart and the boat's instruments are accurate, the "map" IS always showing reality. I think what you are looking for is perhaps beyond the scope of most straight up nav programs and gets into the field of routing and race software, you're looking for the computer to exhibit a bit of intelligence and to make decisions based on some rather large variables. I think it's an intriguing idea but would be very difficult to implement successfully as you'd have to start using some fuzzy logic with systems that are primarily designed to achieve precision.

As I think more of this, I think it could be relevant to always use half intersecting angle as "waypoint approach" condition, but in combination with a distance circle. To cover my needs I could set a fairly large circle radius (purple in my updated illustration, I tried to get it to show inline without success) if the conditions permit, but still take advantage of the "half intersecting angle" to not reach the waypoint too early. Best of both...

Yes, I agree that a method to deal with a missed waypoint would be useful and as I said previously, that method exists already in the NMEA standard with the course perpendicular (the problem with the "half intersecting angle" is that on the outside of your turn, you end up sailing further than you need to to "pass" the WP-additionally, if you're at the end of a route or just going to 1 WP, you can't calculate the 1/2 intersecting angle). The question then becomes how does the boat's autopilot deal with that, does the AP (and/or the Mac) treat it as an "end of route" situation and just keep on at the present heading or does it give you the option to go "Auto Next"? I believe that Raymarine systems would deal with it as an end of route but I'm not sure...

I haven't looked too close at SailTimer yet, but I'm not sure how it would cover these needs. It seems to be more aimed at windward optimization.

SailTimer plots WPs and laylines that are optimized based on a boat's polars(both up and down wind) given a course A -> B. It'll calculate and create new WPs and then "move" them based on wind direction/speed in theory alliviating this entire problem.