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# How far am I from directly opposite the Ranch?

David O'Meara
Rancher
Posts: 13459
Following on from the thread here, assuming the Ranch's physical location is Denver, and I'm in Perth, West Oz, what is the approximate distance (as the crow flies) from my location to the point directly opposite the Ranch?
There should be enough research and maths to keep someone out of trouble for a while

David O'Meara
Rancher
Posts: 13459

HS Thomas
Ranch Hand
Posts: 3404
You should relocate to a location with a latitude 8 degrees North and
be in a timezone GMT + 0200. ( using cac Windows times ).
Denver is 40 degrees North
Perth is 32 degrees South
An GMT hour west of Nairobi ( GMT + 0300) and 8 degrees North of the Equator.
It's 70 miles per degree, I believe.
I am sure if we try hard enough we'll find a town for you, Dave.
Eldoret?
Eldoret is bang on the Equator .
Longitude: 035� 17' E
Latitude: 00� 32' N
A village 560 miles north of Eldoret and a GMT hour west of Nairobi.
Sorry no major cities.
If you like it by the sea, try working the other way.

regards
[ August 27, 2003: Message edited by: HS Thomas ]

HS Thomas
Ranch Hand
Posts: 3404
But if you want to be closest to your two fav places , Denver,CO and Perth,Aus now you know.
To be perfectly upside-down from Javaranch I am sure someone will come up with a solution!
regards
[ August 27, 2003: Message edited by: HS Thomas ]

HS Thomas
Ranch Hand
Posts: 3404
If south is always opposite of north and east is right of west, you will be completely upside down at
40 degrees S and 105 degrees E.
Denver , Colarado is at 40 degrees N and 105 degrees W.
That should take you 70� to the left of Wellngton,NZ 40�S 175�E
40�S 105�E
This confluence has not been visited, or indexed.
Type: Water: 1095 km (680 mi.) from land
regards

Carl Trusiak
Sheriff
Posts: 3341
Hum, I got a little closer on the lat long's
Denver 39.75, 104.91
Perth 31.95, 115.87

1312.68 Kilometers

HS Thomas
Ranch Hand
Posts: 3404
I feel a diagram coming up.

I have been unreliably informed that :
1 deg lattitude = 111 km
1 deg longitude = 65 km
So the sides of the |_ angled triangle are 888 km (a) and 715 km (b)
The distance between the two points as the crow flies ,c is

= 1140 km approx. for a tunelling crow!
===============
I prefer Carl's way,though (Genius at work)
Pure Math over geography. I can't believe the earth's radius would add approx 200 km to the journey over a few degrees.I must have got it wrong. But then again the earth is huge.
Since DOM point is Type: Water: 1095 km (680 mi.) from land I'd dumb down
Carl's figure to be closer to mine. Crows have small eyes so keep close to the surface(not much higher than a Crow's nest) , unlike eagles who may keep to a higher flight path. :roll:
The poor things have been programmed to think the earth is a perfect sphere.
regards
[ August 27, 2003: Message edited by: HS Thomas ]

David O'Meara
Rancher
Posts: 13459
From my own research:
Denver is: 39:46:05N 104:52:22W
Perth is: 31:50:00S 116:10:00E
The opposite side from Denver gives you:
39:46:05S 75:07:38E
Distance from 39:46:05S 75:07:38E to 31:50:00S 116:10:00E for cheats is 3778 km.
Apparently this is only 220km from land. How far to crows fly?

HS Thomas
Ranch Hand
Posts: 3404
The opposite side from Denver gives you:
39:46:05S 75:07:38E

New Delhi has a longitude of 77 degrees E.
By Dave's calculations (presume it is 180 - 105 = 75 ) the opposite of Denver is on the same longitude as New Delhi but 40 degrees S) and not - east is directly right of west - as I had asssumed .
Can anyone explain why the opposite longitude to Denver is 75 degrees E?
regards
[ August 28, 2003: Message edited by: HS Thomas ]

Jim Yingst
Wanderer
Sheriff
Posts: 18671
Can anyone explain why the opposite longitude to Denver is 75 degrees E?
If Denver is at 75 W (75 degrees west of you Greenwichites) then the opposite longitude is 180 degrees away. We could call it 255 W I suppose, but we prefer to measure in the opposite direction (subtract 360 and change sign) to get 75 E.
As for the original question, here's how to calculate the distance along the earth's surface. This assumes the Earth is a perfect sphere, using Carl's numbers. We use the property that the dot product of two vectors is equal to the product of their magnitudes times the cosine of the angle between them - which allows us to solve for that angle if everything else is known.

Since it turns out that the curvature of the Earth makes remarkably little difference in this case, I also calculated how far Dave is from Denver itself, in addition to the distance from the point furthest from Denver:

Obviously, I didn't bother to round to significant figures here.

Michael Matola
whippersnapper
Ranch Hand
Posts: 1826
5
Charts, figures, maps!
It takes a liberal arts major to point out that opposite points on a sphere are "antipodes."

HS Thomas
Ranch Hand
Posts: 3404
posted by Jim Yingst:
We use the property that the dot product of two vectors is equal to the product of their magnitudes times the cosine of the angle between them - which allows us to solve for that angle if everything else is known.

Tell me that has a Pythagorean ring to it and this luddite Greenwichite (me) hasn't given him (Pythagorus) cause to say "So this is how it feels to play for the Bengals?" or "Maybe I should've inhaled!".
Well, that's two people that go it wrong unless DOM knows something he is not telling us.
regards
[ August 28, 2003: Message edited by: HS Thomas ]