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Old 12-01-2013, 06:41   #301
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Re: Distinct Activities: Shackled by a Common Name?

This is all starting give me a ----- ------!
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Old 12-01-2013, 07:25   #302
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Quote:
Originally Posted by CaptForce

No, 'sorry to say, putting mountain climbing gear on the ant does nothing for me. I've come some distance in accepting that the constant heading track and the GPS shortest distance track are in final outcome of idential time, with variables in distance and speed, but I still see no mathmatical advantage in time traveled with the constant heading plan. Both are vector summations.

If we look at another analogy, we can consider that employing the constant heading plan is slapping down a $100 bill for the task and the use of the GPS is paying a penny at a time to toal 10,000 payments.
Oh dear

if i finish the Mathematica vector models you'll see visually that the GPS method is only the same where there is no cross tide component. In all others cases computing the CTS vector is more efficient ( we have to plot how efficient ) , assuming you maintain the plotted speed and have accurate tidal stream data

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Old 12-01-2013, 08:08   #303
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Re: Distinct Activities: Shackled by a Common Name?

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No, 'sorry to say, putting mountain climbing gear on the ant does nothing for me. I've come some distance in accepting that the constant heading track and the GPS shortest distance track are in final outcome of idential time, with variables in distance and speed, but I still see no mathmatical advantage in time traveled with the constant heading plan. Both are vector summations.

If we look at another analogy, we can consider that employing the constant heading plan is slapping down a $100 bill for the task and the use of the GPS is paying a penny at a time to toal 10,000 payments.
Back to the woodshed!

You don't need an ant, if it doesn't work for you. But there are a couple of really concrete examples above which show very clearly that GPS shortest distance track is disastrously wrong for crossing any moving body of water unless only it is moving right along the rhumb line, or unless it is moving at a constant speed and direction (these are the only cases where the two approaches coincide). The more the body of water moves around, the worse off you are traveling in a straight line across the bottom.

You GPS plotted rhumb line is a line over the bottom -- doesn't help you getting across a moving body of water. That is because you sail in water, not over the bottom. It's all laid out pretty well above.

Dave will give you some concrete mathematical examples when he gets his Mac fired up
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Old 12-01-2013, 10:18   #304
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Re: Distinct Activities: Shackled by a Common Name?

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Back to the woodshed!

.......................... unless only it is moving right along the rhumb line, or unless it is moving at a constant speed and direction (these are the only cases where the two approaches coincide)....................

I agree and I made these same statements in post 267.

..........
You GPS plotted rhumb line is a line over the bottom -- doesn't help you getting across a moving body of water. That is because you sail in water, not over the bottom.........................

Certainly, by any plan the boat will be sailing in the water and the goal will be to reach a fixed point after starting from a fixed point and during the traversal you will be moving over the bottom at all times. It's not my purpose to appear obtuse, but this advice to ignore progress over fixed points toward the destination does not make much sense to me.
All traditional navigation would seem to honor coordinates that represent these fixed locations wether they are at the end points of the passage or all the points between. 'calling out from the woodshed!
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Old 12-01-2013, 10:49   #305
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Re: Distinct Activities: Shackled by a Common Name?

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Which is great, the ant by now is knackered and giddy and any further analogies will doubtless prove worthless
No this ant is feeling very feisty LOL. It had only had to trudge along a straight line. All its mates trying to keep a straight track relative to the table have been zig zagging all over the table cloth and are the ones that are knackered .
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Old 12-01-2013, 10:58   #306
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Re: Distinct Activities: Shackled by a Common Name?

Andrew, a few other thoughts for your consideration:

I have heard it postulated that the world may be round not flat. Care to modify your model?

I can't keep silent any longer. I prefer blue and white checks on my tablecloths to red and white ones. So can I request another modification to your model?

Have you realised that it puts a whole fresh aspect to end of the world theories? It is simply when we run put of tablecloth or table .
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Old 12-01-2013, 16:31   #307
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Re: Distinct Activities: Shackled by a Common Name?

I hate to point this out, but ants can stick to the ceiling.

So what happens when the belt goes under the treadmill, and then the ant is suddenly up-current of it's destination?
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Old 12-01-2013, 19:01   #308
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Re: Distinct Activities: Shackled by a Common Name?

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Originally Posted by Seaworthy Lass View Post
Andrew, a few other thoughts for your consideration:

I have heard it postulated that the world may be round not flat. Care to modify your model? .
I flunked the paper where they dealt with transforms between regular and spherical trig. My model is strictly for the flat-earth fraternity slash sorority

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I can't keep silent any longer. I prefer blue and white checks on my tablecloths to red and white ones. So can I request another modification to your model?.
Yes, in fact if you check back I think I did mention that other colour schemes were available. If I didn't, I meant to

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Have you realised that it puts a whole fresh aspect to end of the world theories? It is simply when we run put of tablecloth or table .
I think you might have allowed your tablecloth of thinking to become stained by Maya-nnaise.

I prefer to stay away from the edges of the world, and trust that as one tablecloth departs, another will always be there to take its place.
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Old 12-01-2013, 19:02   #309
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Re: Distinct Activities: Shackled by a Common Name?

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I hate to point this out, but ants can stick to the ceiling.

So what happens when the belt goes under the treadmill, and then the ant is suddenly up-current of it's destination?
We've moved on from treadmills, now we're using a square table and a checkered cloth. Please try to keep up

In order to avoid a proliferation of ant retention events, it is recommended that you fit a radiused hard-metal trim around the edges of your table, to dislodge the tiny crampon points from the tablecloth, enabling the ants to achieve freefall off the edge of the earth as they know it.
One can only hope there is not widespread antipathy, or even antagonism, to this enhancement of the model.

A fringe benefit of crampons (which require that the ants are fitted with substantial boots) is that they increase the weight of any ants which happen to be of the flying variety beyond their rated threshold for takeoff. We have to trust that we will not have the misfortune to encounter Jonathan Livingstone Ant, known to close friends as Jonathant L, or J-L.
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Old 12-01-2013, 19:13   #310
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Re: Distinct Activities: Shackled by a Common Name?

Won't free-fall harm the ant, thereby enraging the pro-animal folks, setting off lawsuits and causing the NFL to re-name teams?

Harming ants merely for the sake of demonstrating theoretical currents seem selfish in the extreme.

Were any ants harmed in the preparation of this thread?
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Old 12-01-2013, 19:33   #311
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Re: Distinct Activities: Shackled by a Common Name?

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Won't free-fall harm the ant, thereby enraging the pro-animal folks, setting off lawsuits and causing the NFL to re-name teams?

Harming ants merely for the sake of demonstrating theoretical currents seem selfish in the extreme.

Were any ants harmed in the preparation of this thread?
We've only used one since the advent of the tablecloth, and s/he (eyesight's not what it was) was kept well away from the edges.

The treadmill precursor (ie the one which was formerly and perhaps formally cursed, eg "not another friggin treadmill to cross !") was conveniently of unspecified length, so it could have been infinite, or at least long enough for the ant to die of old age before confronting the singularity.

If you wish to be more adventurous with your construct, on your own head be it! *

If you are one of those who are anti-ant, and propose instead to use, say, a dog, a chicken and a sack of corn, you had better give some serious thought which pairs can safely be left on the same bank.

(summons up a mental picture of an ant swinging a tiny ice-axe* and front-pointing up some unfortunate's forehead )

(* ant-he-climb-axe)
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Old 12-01-2013, 20:03   #312
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Re: Distinct Activities: Shackled by a Common Name?

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Won't free-fall harm the ant.....?

I'm further reminded of something Stephen Jay Gould pointed out, in a wonderful essay on scaling, in which he spun an interesting line of reasoning as to why the giant insects, the size of elephants, beloved of B grade movie directors, are not encountered elsewhere than in their fevered imaginations.

He pointed out that (as sailors well know) making something the same shape but twice the length means the surface area will be four times, and the volume (and hence mass) eight times as great.

He said that an insect the size of an elephant would require similar design features to an elephant.

He further said (quite interestingly, I thought) that if you dropped a variety of animals down a mineshaft, starting from an elephant and finishing with a spider, (and you thought I was harming animals with MY feeble fantasies !) something along these lines might be observed:

The elephant would explode, the mountain goat might survive but not walk away, the cat would probably do both (might even simply shake itself and run away), and the spider would wonder why it went dark.

.... so I think the average ant, even equipped for alpinism, would probably fare OK, unless a crampon wound were to be self inflicted. Given that they're a 6x6 configuration, I think they could get by with a limb omission or two.

(would that make them an antputee?)
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Old 12-01-2013, 20:08   #313
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Re: Distinct Activities: Shackled by a Common Name?

To through another wrench into things ants navigate by smell...useing trails they or their "buddies" have traveled.......How this or the ant analogy in the first place has anythign to do with the thread I don't have a clue.
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Old 12-01-2013, 20:26   #314
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Re: Distinct Activities: Shackled by a Common Name?

Wait, wait, wait. I'm still trying to catch up.

I'm glad Dockhead brought up concrete, because I'm an expert at concrete. I've placed more concrete than most folks have walked on.

But I'm not sure how concrete bears on our ant, or on navigation.

And if concrete is a navigational aid, then I won't need to study navigation.
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Old 12-01-2013, 20:45   #315
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Re: Distinct Activities: Shackled by a Common Name?

At the maritime academy it was drilled into our heads for four years to use all of your sources for obtaining a fix, and I still believe this. As good as GPS is, it is still just one source.
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