XTE and Arrival Circle radius
by Moonshadow on 27-Aug-2013

The only way to adjust the arrival circle radius seems to be linked to cross track error. This is not ideal when using an autopilot on a long route where XTE is not important but accurate turning at the mark is important. Is there a way to adjust them independently?


27-Aug-2013 capt6650

You can adjust the arrival circle independently of XTE by selecting the waypoint properties. In the waypoint properties under general, you can tell CE how big the arrival circle radius is. There is a box at the lower right that makes the adjustment. You can also just click on the arrival circle and drag it bigger or smaller.

27-Aug-2013 Rose Point Staff Member stevenh

To expand a bit on what capt6650 said:

There is no relationship between the arrival circle radius and XTE. There is also nothing, aside from XTE precision in the Autopilot options, you can set (or would be possible to set) in Coastal Explorer that will impact how your autopilot behaves with respect to XTE. The only other XTE adjustment in Coastal Explorer is an Alert that warns you when your XTE is greater than a certain value (0.25nm by default). This value is represented in our XTE instruments by the "green zone."

For a bit more on autopilots, we simply tell the autopilot what the XTE is and it does whatever it was designed to do with it. There's no way for us to tell the autopilot that it should be more or less picky about how it treats XTE under different circumstances.

The Arrival Circle Radius does affect the autopilot, but only by giving you control over when Coastal Explorer transitions to the next waypoint, which also gives the autopilot a new position to steer towards and a new leg to calculate XTE against. But even if you pass the waypoint outside the arrival circle, we will still switch to the next waypoint when you cross the angle bisector, which is the line that crosses through the waypoint and appears to cut the arrival circle in half, but you have to imagine that this line continues on past the circle.

I hope this clarifies things.

more on Arrival Circle Radius . . .
27-Aug-2013 Cullins

I go through my critical waypoints and tighten the arrival circle down to a very small diameter. Failure to do so can result in the autopilot turning inside a (perhaps) critical buoy. I've asked Rosepoint to either allow a global change to ALL waypoints in a route, or set a different default value to be used for all new waypoints. As usual, a simple and useful change like this has fallen on deaf ears - instead we have a "new improved" interface . . . Whoopdee doo! Mike.

28-Aug-2013 Moonshadow

I was not clear in my original in that I was asking about changing arrival circle and XTE both independently and GLOBALLY. I understand now about XTE and autopilot and I guess global control of arrival circle is currently on a "wish list"?

Thanks for the help

Arrivial Circle Radius
05-Sep-2013 lcrass

I have the same concern about some arrival circles being too large. I would really like the capability to adjust a default setting for arrival circle size. In my cruising in British Columbia, I frequently cruise though narrow channels. The large arrival circles trigger the next waypoint course adjustment too early. If you aren't paying close attention, in some cases, the new course setting can run you aground. I know they can be adjusted individually at each waypoint however.

Global Change for Arrival Circle Radius is needed!
23-Sep-2013 Alex_Benson

Reducing the ACR for a narrow and winding route is BY FAR the most "mouse-intensive" process in CE. Visualize an old guy trying to reduce the ACR for a route: 1-zoom in to a waypoint to see the AC clearly, 2-look closely to grab just the edge of the AC, 3-move mouse to reduce radius while keeping one-eye on the AC Radius box (on the left) to say 50 yards. 4-unzoom to see the next waypoint, and start all over for the next waypoint. Now repeat this say 50 times for a long, narrow and winding route like Rocky Pass, El Capitan Pass or Zimovia Strait in Alaska. It would be so nice to have a box in the Route Properties window to set the default AC radius for all waypoints of a route.

Alex on Wild Blue, SF Bay

ACR and Narrow Winding Channels
24-Sep-2013 krogenguy

The "Wheel Over Line" option under routes worked well for our style of autopilot operation. AP is nice to have, however there are times when we become too enamored with technology. Places like Rocky Pass and numerous others in SEAK and BC really do require looking out the window while driving the boat. Not every rock out there is on the chart even though NOAA and CHO have done really great jobs at mapping the most prominent hazards. Just like to old days of paper charts the skipper needs to compare the view out the window with the one on the plotter.

27-Sep-2013 Rose Point Staff Member brad

We are about to make another preview release available and it includes the ability to change more than one arrivial circle at a time. I realize it is not exactly what some of you are asking for, but it's a start. We still have the ability to set a default radius on our list but wanted to at least make it possible to adjust more than one at a time.