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Offline Tumeni

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Re: Latitude and longitude - please enlighten me
« Reply #60 on: July 11, 2020, 12:19:01 PM »
For FE to be true, either (1) lines of longitude are not straight or (2) lines of longitude do not converge at the Poles.

Lines of lat or long are bisected by angles, the difference between such lines being expressed in degrees of angle.

By definition, this has no meaning on FE. Where would you draw the angle? Where do the lines or vectors forming the angle meet?
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Not Flat. Happy to prove this, if you ask me.
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Nearly all flat earthers agree the earth is not a globe.

Nearly?

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Offline GreatATuin

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Re: Latitude and longitude - please enlighten me
« Reply #61 on: July 11, 2020, 12:37:32 PM »
Take it as a thought experiment: for one moment, forget the geometrical definitions of latitude and longitude, just consider them as coordinates of a location on Earth.

The point is that we can determine latitude and longitude through observation of celestial objects and measurements of time. And conversely, knowing latitude and longitude allows us to know for example at what time the Sun rises and sets on a given date.

Of course, the mere fact that we can use angles as coordinates should tell us something about the shape of the Earth. But let's start with the basics, and let's see if someone denies the reality of the concept of latitude and longitude.
Nearly all flat earthers agree the earth is not a globe.

you guys just read what you want to read

Offline edby

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Re: Latitude and longitude - please enlighten me
« Reply #62 on: July 11, 2020, 04:11:27 PM »
My statements don't actually mention "straight lines",

I agree, I was just wondering if one could add a further statement that longitude lines are the shortest distance between two points, to see if that is a point of disagreement.

Offline iamcpc

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Re: Latitude and longitude - please enlighten me
« Reply #63 on: August 04, 2020, 06:39:46 PM »
I've read a number of posts where latitude and longitude are dismissed by FErs because they are based on a globe earth.

Robin,

I've researched this and I'm also confused about the claim because we have been able to navigate using the stars without using the words "Longitude" and "Latitude"




In terms of Latitude it does not appear to me to be based on a spherical coordinate system. It appears to be based on where you are, in relation to the North star. This was made clear to me when I learned about the Kamal.

https://en.wikipedia.org/wiki/Kamal_(navigation)


The video below discusses the Kamal around 2 minutes.



So is it only the longitude part of the system which is based on a spherical earth?



Re: Latitude and longitude - please enlighten me
« Reply #64 on: August 05, 2020, 08:49:20 AM »
I've read a number of posts where latitude and longitude are dismissed by FErs because they are based on a globe earth.

Robin,

I've researched this and I'm also confused about the claim because we have been able to navigate using the stars without using the words "Longitude" and "Latitude"




In terms of Latitude it does not appear to me to be based on a spherical coordinate system. It appears to be based on where you are, in relation to the North star. This was made clear to me when I learned about the Kamal.

https://en.wikipedia.org/wiki/Kamal_(navigation)


The video below discusses the Kamal around 2 minutes.



So is it only the longitude part of the system which is based on a spherical earth?

I agree, you don't need to be on a spherical earth for latitude to have a meaning and it's undoubtedly useful for navigation. I would really like to hear from a range of FErs whether they would accept this and if not, why not?

I'd go further and say I don't believe there is an issue with longitude either. In principle, finding your longitude is easy. Find the exact time when the sun was due south at Greenwich UK. Find the exact time when the sun is due south at your current location. Work out the time difference. If it's 1 hour, then you are 15° away from Greenwich. This can work on a flat earth just as well as a spherical one, it's simply making use of the fact that the sun appears to travel across the sky at 15° per hour, nothing more. The sun certainly does this, it's easily observed, so if the earth is flat, then it's doing this on a flat earth, so the method still works.

In practice it's not quite as simple as that because the 15° per hour is only an average, it does speed up and slow down a bit throughout the year, but there are known ways to correct for this (see equation of time https://en.wikipedia.org/wiki/Equation_of_time).

Very informative video by the way.

Offline iamcpc

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Re: Latitude and longitude - please enlighten me
« Reply #65 on: August 06, 2020, 07:14:30 PM »
I'd go further and say I don't believe there is an issue with longitude either. In principle, finding your longitude is easy. Find the exact time when the sun was due south at Greenwich UK. Find the exact time when the sun is due south at your current location. Work out the time difference. If it's 1 hour, then you are 15° away from Greenwich. This can work on a flat earth just as well as a spherical one, it's simply making use of the fact that the sun appears to travel across the sky at 15° per hour, nothing more. The sun certainly does this, it's easily observed, so if the earth is flat, then it's doing this on a flat earth, so the method still works.


The main issue that I have with longitude being shape agnostic is that it a lot more complicated to calculate and was not really done by ancient navigators when the FE concept was much more mainstream than it is now.  It's more modern. It's not something you can calculate with sometime as simple as some rope and a board. Claims that it is based on a spherical coordinate system, from my perspective, are much more challenging for me to understand or offer an alternate theory to.

With latitude it seems to me that there is strong evidence that a navigator who calculated latitude and thought the earth was flat would do so in a similar way to a navigator who thought the earth was round.