ice exclusion zone for VG
Post by iconPost by Tigrou26 | 2020-10-21 | 10:09:49

Do you know if it is possible to find the numerical coordinates of the ice exclusion zone of the Virtual Regatta Vendee Globe ( the red line that you see around the antartic continent ?

commenticon 35 Comments
Post by iconPost by LinusVanpelt | 2020-10-21 | 14:18:42
Yes it's possible ;)
You can find it, on the official VG web site, in annex to the rules, & similar to the VR limits
Post by iconPost by Tigrou26 | 2020-10-21 | 15:06:05
I know the official data but what I want to be sure is that VR use the same one
Also what I want to know is : is there somebody who know how VR send these information? Where can we find them in the WS ? Are these information sent by VR ? and How?

Post by iconPost by Hardtack | 2020-10-21 | 15:34:59
Switch on the debugger (press F12) to see Network traffic.
Ice limits are in the getboatinfos response:

0: {lat: -56, lon: -180}
1: {lat: -56.4167, lon: -175}
2: {lat: -56.25, lon: -170}
3: {lat: -55.6667, lon: -165}
4: {lat: -54.75, lon: -160}
5: {lat: -53.9167, lon: -155}
6: {lat: -53.6667, lon: -150}
7: {lat: -53.6667, lon: -145}
8: {lat: -53.6667, lon: -140}
9: {lat: -53.6667, lon: -135}
10: {lat: -53.9167, lon: -130}
11: {lat: -54.0833, lon: -125}
12: {lat: -54.25, lon: -120}
13: {lat: -54.6667, lon: -115}
14: {lat: -55.25, lon: -110}
15: {lat: -55.75, lon: -105}
16: {lat: -56.25, lon: -100}
17: {lat: -57, lon: -95}
18: {lat: -57.75, lon: -90}
19: {lat: -58.5, lon: -85}
20: {lat: -59, lon: -80}
21: {lat: -58.75, lon: -75}
22: {lat: -58, lon: -70}
23: {lat: -57, lon: -65}
24: {lat: -56, lon: -60}
25: {lat: -55, lon: -55}
26: {lat: -52.25, lon: -50}
27: {lat: -49, lon: -45}
28: {lat: -48, lon: -40}
29: {lat: -46, lon: -35}
30: {lat: -45, lon: -30}
31: {lat: -44, lon: -25}
32: {lat: -43.5, lon: -20}
33: {lat: -43, lon: -15}
34: {lat: -43, lon: -10}
35: {lat: -43.5, lon: -5}
36: {lat: -43.5, lon: 0}
37: {lat: -43.6667, lon: 5}
38: {lat: -43.8333, lon: 10}
39: {lat: -44.0833, lon: 15}
40: {lat: -44.4167, lon: 20}
41: {lat: -44.8333, lon: 25}
42: {lat: -45.3333, lon: 30}
43: {lat: -45.9167, lon: 35}
44: {lat: -46.5833, lon: 40}
45: {lat: -47.25, lon: 45}
46: {lat: -47.9167, lon: 50}
47: {lat: -48.75, lon: 55}
48: {lat: -49.6667, lon: 60}
49: {lat: -50.5833, lon: 65}
50: {lat: -50.9167, lon: 70}
51: {lat: -50.9167, lon: 75}
52: {lat: -50.6667, lon: 80}
53: {lat: -50.4167, lon: 85}
54: {lat: -50, lon: 90}
55: {lat: -49, lon: 95}
56: {lat: -47.75, lon: 100}
57: {lat: -46, lon: 105}
58: {lat: -46, lon: 110}
59: {lat: -46, lon: 115}
60: {lat: -46, lon: 120}
61: {lat: -48.8333, lon: 125}
62: {lat: -50.75, lon: 130}
63: {lat: -51.9167, lon: 135}
64: {lat: -52.25, lon: 140}
65: {lat: -52.4167, lon: 145}
66: {lat: -52.75, lon: 150}
67: {lat: -53.25, lon: 155}
68: {lat: -53.8333, lon: 160}
69: {lat: -54.25, lon: 165}
70: {lat: -54.8333, lon: 170}
71: {lat: -55.4167, lon: 175}
72: {lat: -56, lon: 180}

Post by iconPost by YourMomSA | 2020-10-21 | 16:08:44
Nice! Are we able to answer some additional questions (assuming VR didn't answer these themselves somewhere that I haven't seen, since I haven't registered yet...)...

-Is the limit between points the great circle line or rhumb?

-Does it appear to be shown accurately in the UI?

-What happens if you hit or cross the limit?

-Will it be shown in Dashboard's map, and if so, how confident are we in its accuracy there at max zoom, relative to how VR's engine will apply it?


The last time I can recall VR having an ice limit was the last Vendee. If I remember correctly, you got a severe speed penalty until you returned to the correct side of the line, and maybe also for 5 more minutes after getting to the correct side, or something like that. I think the lines were rhumb, so I think if you were able to get to a straight horizontal line and set your course to exactly 90.0 just North of it, you were safe... But if you used waypoints, the waypoints would navigate using great circle, so you'd violate it. That was an issue, but for valid reasons. The other issue was that if you sailed toward the line and then altered course away from it, it would still decide you had violated the line if your projected course was going to cross it within the same 10-minute cycle, or something like that. That was a problem for bad reasons. I think I fouled that 2 or 3 times. Drove me nuts.
Post by iconPost by zezo | 2020-10-21 | 19:16:13
They look like straight lines in Mercator projection, so probably rhumb lines. Or just linear interpolation - should be close enough.

As you note, With GC the "horizontal" lines at 70E-75E 105E-120E would be slightly curved South, and they are not. But the it's a small difference, so may just not be visible. Thanks for the reminder about the waypoints.

Polars say 30% speed in the ice zone ("iceSpeedRatio": 0.3)

Google maps use GC by default. Not sure if the current API can draw rhumb lines, but it probably can - the object has "geodesic" attribute.
Post by iconPost by Hardtack | 2020-10-21 | 19:19:48
I didn't see any further info from VR either, but Pat-Rock just opened a thread on ice limits. Quote:

En effet, en navigation dans le grand Sud votre trajectoire entre deux points, pourra ne pas être rigoureusement rectiligne et vous pourriez dépasser la ligne sans vous en apercevoir.
--
Infact, when navigating in the deep South, your trajectory between two points may not be rigorously straight and you could pass the line without noticing it.

VR seems to display the line segments as rhumb lines, while I chose geodesic lines. Hmm. Probably should have used rhumb lines as well. Somebody tell me.

Post by iconPost by zezo | 2020-10-21 | 19:22:20
Probably yes ;-)

Because of the waypoints.
Post by iconPost by Hardtack | 2020-10-21 | 19:35:53
Ah, right. I'll change to rhumb lines as soon as I can, but have to wait for the current version to be processed by Google first.

Post by iconPost by Hardtack | 2020-10-21 | 20:16:26
Argh, re-reading all the comments I'm confused.

As far as I know a boat uses the shortest path between waypoints - that is, the GC line. By contrast, in heading mode the boat moves on the rhumb line (by definition).

So if the ice limit segments are like waypoints, I really should use geodesic lines on the Google map?! But then VR's own map would be wrong, as it clearly shows straight lines?



Post by iconPost by YourMomSA | 2020-10-21 | 22:29:24
In 2016, the lines were definitely rhumb. The curvature of GC is quite pronounced that far South, and I remember in 2016 seeing that waypoints along the line would violate the line consistently, whereas a straight line compass course did not.
Post by iconPost by Tigrou26 | 2020-10-22 | 08:26:44
Hello Hardtack,

I suppose that you find this message in the network / WS data, but at home I don't find anymore the request and the answer in the message pending /.../WS
I have messages concerning user, money, authorisation , polar but no information concerning getboatinfos, I don't know why ?
I try this on two PC at home, one on Windows 7 and the other on Windows 10 with the same result : no message "getboatinfos"
Perhaps it would be necessary to activate or desactivate somewhere
Thank you for your help
Post by iconPost by Hardtack | 2020-10-22 | 08:49:53
It's not a websocket message, but an XHR request. Select either 'XHR' or 'All' on the debugger Network tab. If you're seeing too many requests, try filtering for 'vro-api'.
Not all getboatinfo responses include leg data. You may have to exit and re-enter VR Offshore. The request should then be sent when you log in to the VG race.
Post by iconPost by Tigrou26 | 2020-10-22 | 09:54:50
Thank you very much, I found them

Post by iconPost by bikeinside | 2020-11-20 | 05:24:59
How can I import this in qtVLM?, found a Link: https://www.dropbox.com/s/r9sag4k52a2qyrj/zea_151120.qbar?dl=0

Post by iconPost by Tigrou26 | 2020-10-22 | 08:38:28
I think that when you use a mode with constant heading (rhumb line) and with a 90° heading you shoud go lightly toward the North and not cut the parallel line, it is not the case with the grand circle navigation (orthodromy) where you will cut the parallel if you want to navigate between two point of the same parallel
Post by iconPost by zezo | 2020-10-22 | 09:09:24
Historically, you can't draw GC lines on a paper chart. So if the sailing instructions say "don't cross the line between such and such points, that would imply rhumb lines

Post by iconPost by Eliric | 2020-10-30 | 01:00:23
Is there any way to have the exclusion zone projected as rhumb lines in the map of the VR Dashboard?





Post by iconPost by Hardtack | 2020-10-30 | 09:40:51
I added the ice limit to the Dashboard a couple of days ago. After some discussion zezo and YourMomSA convinced me of using rhumb lines. Does it not work for you?
Post by iconPost by Eliric | 2020-10-30 | 17:39:10
Thanks Hardtack, I updated my Chrome extension am now I see the exclusion
zone on the map of VR Dashboard.
Post by iconPost by CoreTeam | 2020-10-30 | 13:09:24
I don't know how they programmed things in the game.... but in the real race racing instructions says:

Antarctic Exclusion Zone
The Atlantic Exclusion Zone is a polygon defines by straight-line loxodromic segments linking virtual points.
Post by iconPost by kalle | 2020-10-31 | 12:35:58
@Hardtack. How did you added the limit into Dashboard?
Post by iconPost by Hardtack | 2020-10-31 | 13:56:22
Ice limits are included in a VR boatinfo message sent right after you enter the race.
Post by iconPost by Gaffophone | 2020-10-31 | 17:20:43
Hi Organisation changes a first time AEZ, so to have a look if VR also do ?
Post by iconPost by urbicande | 2020-11-05 | 09:00:17
Hello
In the Vendée Globe games, waypoint N ° 1 is on the ice limit, is this normal, knowing that we have to bypass it?
Post by iconPost by zezo | 2020-11-05 | 09:31:52
Those are just few random points to get you going because the router won't sail around the world by itself.

Ideally, you should be moving your own destination point along the way, observing weather systems and patterns and placing it accordingly.

With the ice limit in the South Ocean keeping the destination few days ahead of you is usually enough, but sometimes there are choices of two distinct routes around a system.

Post by iconPost by urbicande | 2020-11-05 | 10:02:21
Thank you Cvetan, I understood the method well, but although we are not a decision maker I wanted to talk about the N ° 1 passage buoy in the Vendée Globe games?
Post by iconPost by zezo | 2020-11-05 | 10:16:00
There is no buoy in the game itself.

Only proper gate in game is Cape Horn because of the passage N of it.

We are likely to sail very close to the ice limit, so I've placed few random points around the world close to the line.
Post by iconPost by Stevoo | 2020-11-12 | 10:44:42
Good day
Anyone knows what penalties apply for crossing the line? Sorry just saw it above, is that confirmed? the 30% speed in the ice zone ("iceSpeedRatio": 0.3)


Post by iconPost by Tigrou26 | 2020-11-12 | 10:50:52
Yes, your speed is multiplied by 0,3
Post by iconPost by Jeanbern19 | 2020-11-12 | 18:40:09
Hello, will the ice line be depicted on ZEZO as it approaches Antarctica?


Thank you
Post by iconPost by zezo | 2020-11-12 | 19:15:53
Yes. Yo can try a routing in the Southern ocean right now. Tip: Control-click and Shift-click set the routing origin and destination.

I'm treating the line as a hard limit right now, which is fine from routing perspective, but you can't get out once you get too deep below line.

Will probably fix it to adjust the speed once we get close, but OTOH it just wastes time drawing retarded isochrones.
Post by iconPost by YourMomSA | 2020-11-14 | 15:06:42
FWIW... Routings now can reach the ice limit, and it doesn't look like the speed adjustment is in yet. I'm also not seeing it as a hard limit. I'm seeing routings that cross the line at full speed.

Not trying to pressure Cvetan to do something. Just observing it for reference. I don't think it impacts short-term decisionmaking yet.
Post by iconPost by zezo | 2020-11-15 | 21:21:11
Got "Ignore gates" checked?
Post by iconPost by YourMomSA | 2020-11-16 | 03:43:14
Ahhh....!! Thanks! I almost always have that turned on. It hasn't occurred to me that it might affect the ice zone routings.
Post by iconPost by zezo | 2020-11-16 | 08:00:17
It was not affecting it at first, I brought it inside the if() few days after the start.


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