Find the longest great circle segment that avoids the sea

[Brianetta]

The Great Circle Mapper can assist you.

Rules are simple. Find the longest great circle segment that you can, that does not cross the sea. Inland freshwater lakes are fine. The winner is the one with the longest one. For convenience, airport to airport can be specified. If you manage to find a longer one by trivially modifying somebody else's entry, you're guilty of being a bad sport.

A great circle is a circle on the Earth's surface that is of the Earth's diameter. That is, it's a straight line on the surface. This isn't usually a straight line on a map. Google Earth is a useful tool for eyeing them up. This is an interesting game because most documented great circle segments are at sea, where one might stand a chance of following them in real life. (-:

My best so far is Lisbon to Hong Kong at 6849 miles. Let's see all the better ones!

[Lord Aro]

no idea how to use the site, maybe you could tell us how you did it?

[Eddie]

Don't know how to work the site either, but couldn't one from west Africa going through Egypt out into Aisa and near/past China be quite a long one?

EDIT: Ah worked it out...

Something like this:



Freetown - Sierra Leone to Huizhou, Guangdong - China would be 8296 miles.

[Brianetta]

It'd need tweaking by a few miles to avoid the red sea, but that's definitely an improvement on mine, by an additional fifth. Well done!

[CommanderZ]

How can I make it calculate the distance? It doesn't seem to work for me.

This one is probably shorter than eddie's: Marseille - Vladivostok



Btw, I'm not really sure if eddie will be able to find corresponding airports to move the arc a few miles north without cutting its length.

EDIT: Figured it out, only 5615 miles

[Eddie]

Yeah, I spent about half hour trying to find the airports to tweak it but the weren't enough either end and it kept shifting from the Red Sea to the Med. However, there were large towns in both areas that would make it work.

[Kogut]

Only 4704 miles (I tried to connect N & S America)

[Kogut]

Something better (6554)
Granada - Seul

[CommanderZ]

Another not that long one

St. Jacques - Ho Chi Minh City



6492 mi

It looks almost exactly as long as the eddie's 8k arc on the rectangular map, too bad distances are shortening towards the northern pole.

Torus shaped planet would be much better for this kind of thing

[John]

Namibia to far Russia
WVB to UHPT

Distance: 9506 miles



It crosses the very top of the Red Sea, and a little off the Black Sea.
With tweaking it can avoid the Red Sea and hit only the Gulf of Suez. I classed the Black Sea as inland

[CommanderZ]

This line is completely invalid, even if you classify Black SEA as lake and ignore the Kamchatka gulf you are crossing as well and forgot to point out.

Mos important is that the arc must be much flatter to fit between Mediterranean sea and Red Sea. If you correct it, you will end up with Eddie's solution (whether it is correct is dusputable as well, since it seems to cross a tiny bit of Red sea).

Btw, the sea lines should be much more interesting, since the line on land is pretty much obvious (western europe/middle africa -> eastern asia).

[John]

This line is completely invalid, even if you classify Black SEA as lake and ignore the Kamchatka gulf you are crossing as well and forgot to point out.

The lack of mention for the Kamchatka gulf is because it is completely irrelevant. I was using airports as a convenience factor - there is plenty of fiddle room in that sector of the map to tweak it so it does stay on land. Unfortunately there aren't many airports up there to use.

In terms of fiddling the line in google earth, it easily misses the Kamchatka Gulf by lying a little to the north - or indeed just not stretching the extra few miles to cross it in the first place.

And the Caspian SEA is actually a lake. The definition between the two isn't actually that clear cut. Some lakes are seas and some seas are lakes. Ignoring that, the black sea is actually avoidable through the fiddle factor (but only just).

The only issue remains the Gulf of Suez, and if crossing that invalidates the rules or not.

Interestingly taking the line measurement in metres from google earth, and comparing it to the Great circle milage yeilds two very different answers, any one know why?

[Brianetta]

And the Caspian SEA is actually a lake. The definition between the two isn't actually that clear cut. Some lakes are seas and some seas are lakes. Ignoring that, the black sea is actually avoidable through the fiddle factor (but only just).

The only issue remains the Gulf of Suez, and if crossing that invalidates the rules or not.

I thought I'd covered it fairly unambiguously:

Rules are simple. Find the longest great circle segment that you can, that does not cross the sea. Inland freshwater lakes are fine.

To clarify, the Caspian Sea is not an inland freshwater lake. It's a sizeable salt-water body, and for the purposes of this game, as a marine environment it counts as sea.

The Gulfs of Suez and Aqaba are also marine bodies, although the adjoining Suez Canal may be crossed without penalty. Between the Suez and the Med is a very tight squeeze, and I think that Eddie has demonstrated the sort of angle you would need to get from Africa to Eurasia.

[neob]

It'd need tweaking by a few miles to avoid the red sea, but that's definitely an improvement on mine, by an additional fifth. Well done!

i dont thing that the red sea crossed (more like the canal) but the dead sea might.

[Brianetta]

It was the Gulf of Suez. Perhaps I should have been more specific, but I was more in admiration of the segment than the names of the waters at the time. One or both ends of the segment could be moved north by a few miles to clear it, without crossing any other sea water. That might make the segment a little shorter, but it would still be much larger than any other contender so far.

[CommanderZ]

And the Caspian SEA is actually a lake. The definition between the two isn't actually that clear cut. Some lakes are seas and some seas are lakes. Ignoring that, the black sea is actually avoidable through the fiddle factor (but only just).

Caspian Sea status might be disputable, but Black sea is the sea in exactly the same way as Mediterranean sea. And your line is crossing the Black Sea.

[John]

I thought I'd covered it fairly unambiguously:

Yes, but this is the internet

Thwarted by a 20mile stretch of salt water. I shall have a little play, as I think something can be achieved following parts of my line. Not sure how long it will be though.

And your line is crossing the Black Sea.

And? Did you miss the rest of the post where I said the Black Sea can be avoided by moving the line slightly. The problem is there are no airports in the vicinity of where the line needs to actually go (remember, its doesn't have to be airport to airport - they are just very convenient in great circle mapper) - the image chosen is just a close representation of where the line roughly is. Oh and this seems to be an internet arguement. Hitler


[edit]


Eh voila. EJH - UHPT. Distance a disappointing 5828 miles. (Google earth reports 5946 miles, which is fairly close).

The airport I actually wanted to use was UHPA but Circle Mapper doesn't recognise that.

Tweaking the line to comply with avoiding salt water gives a length of 6583miles.




[edit2]
Tweaking Eddie's solution to avoid the Gulf of Suez (going from Robertsport, Liberia to Hui'an China) Gives an extra 150miles

Total Miles:8450



It clears the Gulf of Suez by 30miles, and the Mediterranean by 13 miles.

[Eddie]

Oh my you bad sport...

[John]

Oh my you bad sport...

I know - I won't be claiming that as mine though

The unfortunate side effects of being ill at home, slightly bored

[CommanderZ]

Hitler

Me? This is not exactly the word you want to call people with in today's politically overcorrect society

Tweaking Eddie's solution to avoid the Gulf of Suez (going from Robertsport, Liberia to Hui'an China) Gives an extra 150miles

This one is nice. I guess we won't get any better than this. :thumbs up: