[CableDawg]

That's like saying the bible is true because it's written down.

A couple of quotes of his:

"There are rivers that flow for hundreds of miles towards the level of the sea without falling more than a few feet — notably, the Nile, which, in a thousand miles, falls but a foot. A level expanse of this extent is quite incompatible with the idea of the Earth's convexity. It is, therefore, a reasonable proof that Earth is not a globe."

By this logic the fact that there are mountains proves that the Earth is round because the highest of the rises to 29,000 feet over a very short span.

"If the Earth were a globe, a small model globe would be the very best - because the truest - thing for the navigator to take to sea with him. But such a thing as that is not known: with such a toy as a guide, the mariner would wreck his ship, of a certainty!, This is a proof that Earth is not a globe."

Such a thing as a model globe is not known?  The earliest globe known of dates from the same period of time in which the Earth was established as a sphere.  Was he just no looking in the right places to find this magical thing or was it one of the things he chose to ignore to bolster his claim?

You obviously completely misinterpreted Rowbothams points there.

A mountain has no bearing on a river. A river has a high point and flows towards sea level. If a river goes across a thousand miles it would inevitably have to conquer the convexity in the form of a hill at some point (flowing up and over)

As far as the globe, what he was saying was that no navigator uses a model globe to travel at sea. They use maps, and celestial methods to do it, if the globe were a true representation they would only need a model globe to navigate.

If that is a representation of your take away from 100 proofs then you clearly have a hard time understanding it at all.

A mountain has as much bearing on the topic at hand as a river.  It's a matter of following logic.  If the perceived flatness of a river proves a flat earth, the perceive rise of a mountain proves a round earth.

Regarding a globe representation, keeping in mind the limited space available on ships (today and especially in the past):

1. Globes are a scaled representation of the earth.
2. Most globes represent thousands of miles in mere inches.
3. A globe can be scaled to represent those thousands of miles in a usable way but it would have to be extremely large, probably on the order of a ten foot diameter (possibly quite larger to accommodate resolution of oceanic features), to be truly useful which would necessitate an independent, specialized room in each and every ship to accommodate it.

1. Maps are scaled representations of the earth.
2. Maps also represent thousands of miles (typical world map) in mere inches but their resolution is easily changed to give a more accurate representation (typical topo grid map).
3. Maps take up very little space.  Even if every ship was required to have 100 maps of differing resolutions and areas the space they take up is a matter of feet (a cabinet not much larger than a typical office desk).

Do you honestly believe that ship builders, navies and naval merchants are or were going to build their ships around a useable globe representation when maps served the purpose just as well?  Do you honestly believe that any of them would give up valuable space to a useable globe representation when a smaller, viable option was/is available?

Prior to the advent of GPS maps were the only available source for navigation (from nation scale to community scale).  Try to imagine how large a globe representation would have to be to give useable navigation information on a national scale and even more so on a community scale.

The fact that maps are used is, in no way, proof of a flat earth. 

[CableDawg]

Each and every one of the photographs I provide is carefully documented: we know exactly where it was taken, we can estimate the maximum altitude, everything is clear.

Each of those photographs provided shows and demonstrates that there is no 59 meter curvature across lake Ontario.

Any photograph showing a partial skyline must provide the following information:

altitude of photographer
distance involved

Let us remember that I have been involved in these kinds of debates many times (involving not only lake Ontario but also the Chicago skyline) and I have won them each and every time.

It really is quite humorous.  FE supporters base their theory on perception and automatically disregard mainstream scientific data out of hand but will take anything that supports their ideas as gospel even if they were not the one who actually perceived that which is documented.

Why is this?

I suspect that I could provide you with exactly what you want and if it doesn't fit your ideas or theories you would demand further information or proof of documentation.  From my short time in this particular forum this has actually been proven time and again.

[TheTruthIsOnHere]

That's like saying the bible is true because it's written down.

A couple of quotes of his:

"There are rivers that flow for hundreds of miles towards the level of the sea without falling more than a few feet — notably, the Nile, which, in a thousand miles, falls but a foot. A level expanse of this extent is quite incompatible with the idea of the Earth's convexity. It is, therefore, a reasonable proof that Earth is not a globe."

By this logic the fact that there are mountains proves that the Earth is round because the highest of the rises to 29,000 feet over a very short span.

"If the Earth were a globe, a small model globe would be the very best - because the truest - thing for the navigator to take to sea with him. But such a thing as that is not known: with such a toy as a guide, the mariner would wreck his ship, of a certainty!, This is a proof that Earth is not a globe."

Such a thing as a model globe is not known?  The earliest globe known of dates from the same period of time in which the Earth was established as a sphere.  Was he just no looking in the right places to find this magical thing or was it one of the things he chose to ignore to bolster his claim?

You obviously completely misinterpreted Rowbothams points there.

A mountain has no bearing on a river. A river has a high point and flows towards sea level. If a river goes across a thousand miles it would inevitably have to conquer the convexity in the form of a hill at some point (flowing up and over)

As far as the globe, what he was saying was that no navigator uses a model globe to travel at sea. They use maps, and celestial methods to do it, if the globe were a true representation they would only need a model globe to navigate.

If that is a representation of your take away from 100 proofs then you clearly have a hard time understanding it at all.

A mountain has as much bearing on the topic at hand as a river.  It's a matter of following logic.  If the perceived flatness of a river proves a flat earth, the perceive rise of a mountain proves a round earth.

Regarding a globe representation, keeping in mind the limited space available on ships (today and especially in the past):

1. Globes are a scaled representation of the earth.
2. Most globes represent thousands of miles in mere inches.
3. A globe can be scaled to represent those thousands of miles in a usable way but it would have to be extremely large, probably on the order of a ten foot diameter (possibly quite larger to accommodate resolution of oceanic features), to be truly useful which would necessitate an independent, specialized room in each and every ship to accommodate it.

1. Maps are scaled representations of the earth.
2. Maps also represent thousands of miles (typical world map) in mere inches but their resolution is easily changed to give a more accurate representation (typical topo grid map).
3. Maps take up very little space.  Even if every ship was required to have 100 maps of differing resolutions and areas the space they take up is a matter of feet (a cabinet not much larger than a typical office desk).

Do you honestly believe that ship builders, navies and naval merchants are or were going to build their ships around a useable globe representation when maps served the purpose just as well?  Do you honestly believe that any of them would give up valuable space to a useable globe representation when a smaller, viable option was/is available?

Prior to the advent of GPS maps were the only available source for navigation (from nation scale to community scale).  Try to imagine how large a globe representation would have to be to give useable navigation information on a national scale and even more so on a community scale.

The fact that maps are used is, in no way, proof of a flat earth.

Who said a river was flat? It's obvious they aren't, because they flow toward the lowest area, as fluids are known to do, in particular sea level. Which is what all water does. It flows from the higher elevation to lower elevation. But there is a vast ocean in which not only does this not happen, it actually bends and contorts and bulges to form a giant spherical surface.

Interesting though, that a paper map has high enough resolution because of a typographical grid that apparently doesn't work on a globe. Also interesting most modern ships don't have anywhere near enough room for a 10 foot globe.

https://www.google.com/search?q=allure+of+the+seas+lobby&biw=1600&bih=765&source=lnms&tbm=isch&sa=X&ved=0ahUKEwixjsqD-rLLAhXIdD4KHRbAC48Q_AUIBigB

[rabinoz]

Interesting though, that a paper map has high enough resolution because of a typographical grid that apparently doesn't work on a globe. Also interesting most modern ships don't have anywhere near enough room for a 10 foot globe.

https://www.google.com/search?q=allure+of+the+seas+lobby&biw=1600&bih=765&source=lnms&tbm=isch&sa=X&ved=0ahUKEwixjsqD-rLLAhXIdD4KHRbAC48Q_AUIBigB

Whatever do you mean by "a paper map has high enough resolution because of a typographical grid that apparently doesn't work on a globe"?
Of course a paper map can be made any scale we like, as it can be stored in a compact flat form. Of course we can now store flat maps or representations of the globe (like Google Earth) in a very compact form on a computer.

With the paper map the we only need large scales of the areas we need to see in details - coasts and harbours.

And what are pictures for? Of course a large ship could carry a large, but how large would it need to be?

Maps for ocean navigation might be to a scale of 1:1,000,000 making a globe at this scale 12,742 km/1,000,000 = 12.74 metres (almost 42 ft).
For coastal navigation maps to a scale of 1:100,000 are commonly used and this globe (at 127.4 m or 420 ft) would not even fit on the largest passenger ship, the  "Allure of the Seas" of Royal Caribbean International line.

Then a port navigation chart at 1:10,000 does get a bit horrendous at 1.27 km or 4,200 ft!

So a bit impractical, though I gather terrestrial globes (but only about 60 cm diam) were taken on some ships.

[Woody]

That's like saying the bible is true because it's written down.

A couple of quotes of his:

"There are rivers that flow for hundreds of miles towards the level of the sea without falling more than a few feet — notably, the Nile, which, in a thousand miles, falls but a foot. A level expanse of this extent is quite incompatible with the idea of the Earth's convexity. It is, therefore, a reasonable proof that Earth is not a globe."

By this logic the fact that there are mountains proves that the Earth is round because the highest of the rises to 29,000 feet over a very short span.

"If the Earth were a globe, a small model globe would be the very best - because the truest - thing for the navigator to take to sea with him. But such a thing as that is not known: with such a toy as a guide, the mariner would wreck his ship, of a certainty!, This is a proof that Earth is not a globe."

Such a thing as a model globe is not known?  The earliest globe known of dates from the same period of time in which the Earth was established as a sphere.  Was he just no looking in the right places to find this magical thing or was it one of the things he chose to ignore to bolster his claim?

You obviously completely misinterpreted Rowbothams points there.

A mountain has no bearing on a river. A river has a high point and flows towards sea level. If a river goes across a thousand miles it would inevitably have to conquer the convexity in the form of a hill at some point (flowing up and over)

As far as the globe, what he was saying was that no navigator uses a model globe to travel at sea. They use maps, and celestial methods to do it, if the globe were a true representation they would only need a model globe to navigate.

If that is a representation of your take away from 100 proofs then you clearly have a hard time understanding it at all.

A mountain has as much bearing on the topic at hand as a river.  It's a matter of following logic.  If the perceived flatness of a river proves a flat earth, the perceive rise of a mountain proves a round earth.

Regarding a globe representation, keeping in mind the limited space available on ships (today and especially in the past):

1. Globes are a scaled representation of the earth.
2. Most globes represent thousands of miles in mere inches.
3. A globe can be scaled to represent those thousands of miles in a usable way but it would have to be extremely large, probably on the order of a ten foot diameter (possibly quite larger to accommodate resolution of oceanic features), to be truly useful which would necessitate an independent, specialized room in each and every ship to accommodate it.

1. Maps are scaled representations of the earth.
2. Maps also represent thousands of miles (typical world map) in mere inches but their resolution is easily changed to give a more accurate representation (typical topo grid map).
3. Maps take up very little space.  Even if every ship was required to have 100 maps of differing resolutions and areas the space they take up is a matter of feet (a cabinet not much larger than a typical office desk).

Do you honestly believe that ship builders, navies and naval merchants are or were going to build their ships around a useable globe representation when maps served the purpose just as well?  Do you honestly believe that any of them would give up valuable space to a useable globe representation when a smaller, viable option was/is available?

Prior to the advent of GPS maps were the only available source for navigation (from nation scale to community scale).  Try to imagine how large a globe representation would have to be to give useable navigation information on a national scale and even more so on a community scale.

The fact that maps are used is, in no way, proof of a flat earth.

Who said a river was flat? It's obvious they aren't, because they flow toward the lowest area, as fluids are known to do, in particular sea level. Which is what all water does. It flows from the higher elevation to lower elevation. But there is a vast ocean in which not only does this not happen, it actually bends and contorts and bulges to form a giant spherical surface.

Interesting though, that a paper map has high enough resolution because of a typographical grid that apparently doesn't work on a globe. Also interesting most modern ships don't have anywhere near enough room for a 10 foot globe.

https://www.google.com/search?q=allure+of+the+seas+lobby&biw=1600&bih=765&source=lnms&tbm=isch&sa=X&ved=0ahUKEwixjsqD-rLLAhXIdD4KHRbAC48Q_AUIBigB

The charts I currently have cover from Baja to Alaska. 

I have one chart that covers that covers the entire area, one that covers the California coast, one that covers southern California, one that covers areas north and south of Los Angeles, one that covers the area closer to Los Angeles, and one that covers the Port of LA.  That is just a small example of the charts that cover the West Coast of the US I have.  How many globe and ellipsoid maps do you think I could carry on my 45' boat?

How do you think I plot courses on those maps?  I use a straight edge and compass which are easy and practical to work with.  I store all those charts in one location.  It is a storage area underneath my navigation table that takes up relatively little room.

How do you propose I store and plot courses with a globes covering the same area? 

Are you really saying it is easier and more practical to navigate using a globe?

[CableDawg]

That's like saying the bible is true because it's written down.

A couple of quotes of his:

"There are rivers that flow for hundreds of miles towards the level of the sea without falling more than a few feet — notably, the Nile, which, in a thousand miles, falls but a foot. A level expanse of this extent is quite incompatible with the idea of the Earth's convexity. It is, therefore, a reasonable proof that Earth is not a globe."

By this logic the fact that there are mountains proves that the Earth is round because the highest of the rises to 29,000 feet over a very short span.

"If the Earth were a globe, a small model globe would be the very best - because the truest - thing for the navigator to take to sea with him. But such a thing as that is not known: with such a toy as a guide, the mariner would wreck his ship, of a certainty!, This is a proof that Earth is not a globe."

Such a thing as a model globe is not known?  The earliest globe known of dates from the same period of time in which the Earth was established as a sphere.  Was he just no looking in the right places to find this magical thing or was it one of the things he chose to ignore to bolster his claim?

You obviously completely misinterpreted Rowbothams points there.

A mountain has no bearing on a river. A river has a high point and flows towards sea level. If a river goes across a thousand miles it would inevitably have to conquer the convexity in the form of a hill at some point (flowing up and over)

As far as the globe, what he was saying was that no navigator uses a model globe to travel at sea. They use maps, and celestial methods to do it, if the globe were a true representation they would only need a model globe to navigate.

If that is a representation of your take away from 100 proofs then you clearly have a hard time understanding it at all.

A mountain has as much bearing on the topic at hand as a river.  It's a matter of following logic.  If the perceived flatness of a river proves a flat earth, the perceive rise of a mountain proves a round earth.

Regarding a globe representation, keeping in mind the limited space available on ships (today and especially in the past):

1. Globes are a scaled representation of the earth.
2. Most globes represent thousands of miles in mere inches.
3. A globe can be scaled to represent those thousands of miles in a usable way but it would have to be extremely large, probably on the order of a ten foot diameter (possibly quite larger to accommodate resolution of oceanic features), to be truly useful which would necessitate an independent, specialized room in each and every ship to accommodate it.

1. Maps are scaled representations of the earth.
2. Maps also represent thousands of miles (typical world map) in mere inches but their resolution is easily changed to give a more accurate representation (typical topo grid map).
3. Maps take up very little space.  Even if every ship was required to have 100 maps of differing resolutions and areas the space they take up is a matter of feet (a cabinet not much larger than a typical office desk).

Do you honestly believe that ship builders, navies and naval merchants are or were going to build their ships around a useable globe representation when maps served the purpose just as well?  Do you honestly believe that any of them would give up valuable space to a useable globe representation when a smaller, viable option was/is available?

Prior to the advent of GPS maps were the only available source for navigation (from nation scale to community scale).  Try to imagine how large a globe representation would have to be to give useable navigation information on a national scale and even more so on a community scale.

The fact that maps are used is, in no way, proof of a flat earth.

Who said a river was flat? It's obvious they aren't, because they flow toward the lowest area, as fluids are known to do, in particular sea level. Which is what all water does. It flows from the higher elevation to lower elevation. But there is a vast ocean in which not only does this not happen, it actually bends and contorts and bulges to form a giant spherical surface.

Interesting though, that a paper map has high enough resolution because of a typographical grid that apparently doesn't work on a globe. Also interesting most modern ships don't have anywhere near enough room for a 10 foot globe.

https://www.google.com/search?q=allure+of+the+seas+lobby&biw=1600&bih=765&source=lnms&tbm=isch&sa=X&ved=0ahUKEwixjsqD-rLLAhXIdD4KHRbAC48Q_AUIBigB

Reread the conversation regarding rivers and the quote from Rowbotham.  The gist (one foot of drop in a thousand miles is miniscule) of his statement is that the Nile is running flat.

A topographical grid does work on a globe but the topographical grid is not what makes a map, or a globe for that matter, scalable.

Regarding maps and scaling them:

1.  World map drawn on a sheet of paper that is 4 foot by 3 foot.  You can see information on a gross scale, i.e. continents, mountains and some major rivers.

2.  Another map drawn on the same size paper representing the Americas.  You can now see information not only on a gross scale but also at a slightly finer scale.

3.  Another map drawn on the same size paper representing only North America.  You can now see even finer detail.

4.  Another map drawn on the same size paper representing only the United States.  You can now see even finer detail.

5.  Another map drawn on the same size paper representing only the area bounded by the Rocky mountains and the Mississippi river.  You can now see even finer detail.

6.  Another map drawn on the same size paper representing only the state of Oklahoma.  You can now see even finer detail.

7.  Another map drawn on the same size paper representing only the western half of Oklahoma.  You can now see even finer detail.

These scaling steps can go on to the point that the user of the map needs.  At any point along the way topographical markings can be made to represent pertinent information.  Just from this example you've got a series of maps that provide information from the gross to the relatively fine which are easily transportable, storable, usable and provide a vast wealth of information.

Scaling a globe works for scaling a globe.  What I mean by this is that you can scale the globe to large or small as needed but you can NOT scale the Americas, North America, the United States, the area bounded by the Rocky mountains and Mississippi river, Oklahoma or the western half of Oklahoma to their own, independent, globe.

Regarding ships not having room:

How big is the mechanism to mount that ten foot globe?

Is the globe stationary and people have to move around it to use it?

If mobile, how big is the mechanism to drive it in multiple dimensions?

If static, how large is the structure to allow people to use it without issue?

There are many other aspects to consider which drive the amount of space a ten foot globe would actually take up.  Go talk to that cruise line and see how agreeable they would be to taking away from passenger space to fit this instrument in their ship when they can accomplish much more with maps that take up far, far less space.  Do the same with military and merchant ships.  Talk them in to giving up valuable space for this model globe mechanism.  You've gained nothing with that comment.

[rabinoz]

As I noted earlier a 10' globe does not show anything like the detail needed for coastal or harbour navigation!
I think some people try to argue otherwise just to be difficult.
If these people don't accept the globe and want a flat earth let us see arguments explaining all the failings in any model we have yet seen!

[TheTruthIsOnHere]

Well I guess most modern navigators would use GPS now instead of traditional maps or globes.

Of course you could have a "digital globe" as well at your discretion to help with your travels. However, the most popular projection for nautical travel apparently is the Mercator projection. Basically the same style of map Google, Bing, Yahoo, Mapquest use, which the digital file version doesn't conform to a spherical or elliptical projection, but it has gotten me where I need to go pretty accurately over the last few years.

Odd, that for digital GPS use the simplest projection seems to be the best way to calculate distances and times. Why didn't google program a geodetic calculus engine into their app to really get it right?

[Woody]

Well I guess most modern navigators would use GPS now instead of traditional maps or globes.

Of course you could have a "digital globe" as well at your discretion to help with your travels. However, the most popular projection for nautical travel apparently is the Mercator projection. Basically the same style of map Google, Bing, Yahoo, Mapquest use, which the digital file version doesn't conform to a spherical or elliptical projection, but it has gotten me where I need to go pretty accurately over the last few years.

Odd, that for digital GPS use the simplest projection seems to be the best way to calculate distances and times. Why didn't google program a geodetic calculus engine into their app to really get it right?

Is the screen your phone or computer use a sphere?

[rabinoz]

Well I guess most modern navigators would use GPS now instead of traditional maps or globes.

Of course you could have a "digital globe" as well at your discretion to help with your travels. However, the most popular projection for nautical travel apparently is the Mercator projection. Basically the same style of map Google, Bing, Yahoo, Mapquest use, which the digital file version doesn't conform to a spherical or elliptical projection, but it has gotten me where I need to go pretty accurately over the last few years.

Odd, that for digital GPS use the simplest projection seems to be the best way to calculate distances and times. Why didn't google program a geodetic calculus engine into their app to really get it right?

You really need to look up UTM (Universal Transverse Mercator,) and WGS 84  (World Geodetic Survey 1984[1]). I think you will find that modern mapping has thought of these things long before you have. But there is much more to it than I could put here, even if I knew enough about it.
Put very roughly the earth is broken up into numerous "grid zones" 6° wide (E-W)  and 8° high (N-S) and each is mapped separately. This covers 80°S to 84°N with Universal Polar Stereographic coordinate system (UPS)  used for polar regions.
There is overlap and quite a few exceptions to avoid unnecessary zone changes on the edge of continents.

If you want more detail you can read up on it.

So, effectively Google Earth and Google Maps (plus many others used by GPS manufacturers and Open Source Maps)  provide all you are asking for.

[1]  Looks like map makers have heard about Geodetic-surveying - mind you that is essentially how maps have been made for centuries!

[Tom Bishop]

Here are my comments I made in another thread about the video in the OP:

That person in the video needs to refute Earth Not a Globe, the authority on the subject, not some random youtuber. The author mentions Spherical Excess as a proof of the earth's rotundity, but has not refuted the Earth Not a Globe chapter on the topic.

[Tom Bishop]

He mentioned lake Ontario during the video.

There is no curvature whatsoever across a distance of 55 km over lake Ontario:

http://forum.tfes.org/index.php?topic=3838.msg80842#msg80842

One photo with insufficient context does not constitute evidence.

What about all the photos that do show skyscrapers with up to 50% of their height obscured?  Or this photo from Niagara-on-the-Lake where you cannot see the Rogers Centre at all:

Rama, like Sandokan said, we need to know the altitude of the observer. If you get close to the sea then the bulges of the ocean build up in the distance and get in the way, providing a small area above eye level, no matter how small, where bodies can shrink behind, much like holding a dime out in front of you and obscuring an elephant in the distance. Samuel Birley Rowbotham spoke about this in Earth Not a Globe. That's why the experiment is done on canals and lakes in the book.

[rabinoz]

He mentioned lake Ontario during the video.

There is no curvature whatsoever across a distance of 55 km over lake Ontario:

http://forum.tfes.org/index.php?topic=3838.msg80842#msg80842

One photo with insufficient context does not constitute evidence.

What about all the photos that do show skyscrapers with up to 50% of their height obscured?  Or this photo from Niagara-on-the-Lake where you cannot see the Rogers Centre at all:

Rama, like Sandokan said, we need to know the altitude of the observer. If you get close to the sea then the bulges of the ocean build up in the distance and get in the way, providing a small area above eye level, no matter how small, where bodies can shrink behind, much like holding a dime out in front of you and obscuring an elephant in the distance. Samuel Birley Rowbotham spoke about this in Earth Not a Globe. That's why the experiment is done on canals and lakes in the book.

  Don't be ridiculous! Of course the earth is concave.   

You just have to look in  https://en.wikipedia.org/wiki/Bedford_Level_experiment:

Other experiments
On 25 July 1896, Ulysses Grant Morrow, a newspaper editor, conducted a similar experiment on the Old Illinois Drainage Canal, Summit, Illinois. Unlike Rowbotham, he was seeking to demonstrate that the surface of the earth was curved: when he too found that his target marker, 18 inches (46 cm) above water level and five miles (8.0 km) distant, was clearly visible he concluded that the Earth's surface was concavely curved, in line with the expectations of his sponsors, the Koreshan Unity society. The findings were dismissed by critics as the result of atmospheric refraction.

  Now, who could doubt that?   

I know talking to you (of the 2 <= π <= 4 fame) is useless, but in https://en.wikipedia.org/wiki/Atmospheric_refraction it does point out that"

Whenever possible, astronomers will schedule their observations around the time of culmination of an object when it is highest in the sky. Likewise sailors will never shoot a star which is not at least 20° or more above the horizon. If observations close to the horizon cannot be avoided, it is possible to equip a telescope with control systems to compensate for the shift caused by the refraction. If the dispersion is a problem too, (in case of broadband high-resolution observations) atmospheric refraction correctors can be employed as well (made from pairs of rotating glass prisms). But as the amount of atmospheric refraction is a function of the temperature gradient, the temperature, pressure, and humidity (the amount of water vapour is especially important at mid-infrared wavelengths) the amount of effort needed for a successful compensation can be prohibitive. Surveyors, on the other hand, will often schedule their observations in the afternoon when the magnitude of refraction is minimum.
Atmospheric refraction becomes more severe when there are strong temperature gradients, and refraction is not uniform when the atmosphere is inhomogeneous, as when there is turbulence in the air. This is the cause of twinkling of the stars and various deformations of the shape of the sun at sunset and sunrise.

[Tom Bishop]

  Don't be ridiculous! Of course the earth is concave.   

You just have to look in  https://en.wikipedia.org/wiki/Bedford_Level_experiment:

Other experiments
On 25 July 1896, Ulysses Grant Morrow, a newspaper editor, conducted a similar experiment on the Old Illinois Drainage Canal, Summit, Illinois. Unlike Rowbotham, he was seeking to demonstrate that the surface of the earth was curved: when he too found that his target marker, 18 inches (46 cm) above water level and five miles (8.0 km) distant, was clearly visible he concluded that the Earth's surface was concavely curved, in line with the expectations of his sponsors, the Koreshan Unity society. The findings were dismissed by critics as the result of atmospheric refraction.

  Now, who could doubt that?   

I know talking to you (of the 2 <= π <= 4 fame) is useless, but in https://en.wikipedia.org/wiki/Atmospheric_refraction it does point out that"

Whenever possible, astronomers will schedule their observations around the time of culmination of an object when it is highest in the sky. Likewise sailors will never shoot a star which is not at least 20° or more above the horizon. If observations close to the horizon cannot be avoided, it is possible to equip a telescope with control systems to compensate for the shift caused by the refraction. If the dispersion is a problem too, (in case of broadband high-resolution observations) atmospheric refraction correctors can be employed as well (made from pairs of rotating glass prisms). But as the amount of atmospheric refraction is a function of the temperature gradient, the temperature, pressure, and humidity (the amount of water vapour is especially important at mid-infrared wavelengths) the amount of effort needed for a successful compensation can be prohibitive. Surveyors, on the other hand, will often schedule their observations in the afternoon when the magnitude of refraction is minimum.
Atmospheric refraction becomes more severe when there are strong temperature gradients, and refraction is not uniform when the atmosphere is inhomogeneous, as when there is turbulence in the air. This is the cause of twinkling of the stars and various deformations of the shape of the sun at sunset and sunrise.

Well, the results of Rowbotham's experiments don't necessarily rule out concavity, but they do rule out convexity.

By the way, Rowbohtam does address atmospheric refraction in Earth Not a Globe.

http://www.sacred-texts.com/earth/za/za14.htm

Many have urged that refraction would account for much of the elevation of objects seen at the distance of several miles. Indeed, attempts have been made to show that the large flag at the end of six miles of the Bedford Canal (Experiment 1, fig. 2, p. 13) has been brought into the line of sight entirely by refraction. That the line of sight was not a right line, but curved over the convex surface of the water; and the well-known appearance of an object in a basin of water, has been referred to in illustration. A very little reflection, however, will show that the cases are not parallel; for instance, if the object (a shilling or other coin) is placed in a basin without water there is no refraction. Being surrounded with atmospheric air only, and the observer being in the same medium, there is no bending or refraction of the eye line. Nor would there be any refraction if the object and the observer were both surrounded with water. Refraction can only exist when the medium surrounding the observer is different to that in which the object is placed. As long as the shilling in the basin is surrounded with air, and the observer is in the same air, there is no refraction; but whilst the observer remains in the air, and the shilling is placed in water, refraction exists. This illustration does not apply to the experiments made on the Bedford Canal, because the flag and the boats were in the same medium as the observer--both were in the air. To make the cases parallel, the flag or the boat should have been in the water, and the observer in the air; as it was not so, the illustration fails.

There is no doubt, however, that it is possible for the atmosphere to have different temperature and density at two stations six miles apart; and some degree of refraction would thence result; but on several occasions the following steps were taken to ascertain whether any such differences existed. Two barometers, two thermometers, and two hygrometers, were obtained, each two being of the same make, and reading exactly alike. On a given day, at twelve o'clock, all the instruments were carefully examined, and both of each kind were found to stand at the same point or figure: the two, barometers showed the same density; the two thermometers the same temperature; and the two hygrometers the same degree of moisture in the air. One of each kind was then taken to the opposite station, and at three o'clock each instrument was carefully examined, and the readings recorded, and the observation to the flag, &c., then immediately taken. In a short time afterwards the two sets of observers met each other about midway on the northern bank of the canal, when the notes were compared, and found to be precisely alike--the temperature, density, and moisture of the air did not differ at the two stations at the time the experiment with the telescope and flag-staff was made. Hence it was concluded that refraction had not played any part in the observation, and could not be allowed for, nor permitted to influence, in any way whatever, the general result.

[rabinoz]

There is so much controversy over the "Bedford Canal" experiment and the fuss afterward that basing a whole movement on that is surely building on quicksand!

https://en.wikipedia.org/wiki/Bedford_Level_experiment
Rowbotham repeated his experiments several times over the years but his claims received little attention until, in 1870, a supporter by the name of John Hampden offered a wager that he could show, by repeating Rowbotham's experiment, that the earth was flat. The noted naturalist and qualified surveyor Alfred Russel Wallace accepted the wager. Wallace, by virtue of his surveyor's training and knowledge of physics, avoided the errors of the preceding experiments and won the bet. The crucial step was to set a sight line 13 feet (4 m) above the water, and thereby avoid the effects of atmospheric refraction. Despite Hampden initially refusing to accept the demonstration, Wallace was awarded the bet by the referee, editor of The Field sports magazine. Hampden subsequently published a pamphlet alleging that Wallace had cheated and sued for his money. Several protracted court cases ensued, with the result that Hampden was imprisoned for threatening to kill Wallace and for libel. The same court ruled that the wager had been invalid because Hampden retracted the bet and required that Wallace return the money to Hampden./quote]

Yes Hampden "won" the money, but with a reputation in shatters!

Look you have "a snowflakes chance in hell" of any wide acceptance till you have a model with:
an accurate map that can be used for find distances and directions accurately,
a model that can explain observed phenomena, sunrises, sunset etc.

[Tom Bishop]

There is so much controversy over the "Bedford Canal" experiment and the fuss afterward that basing a whole movement on that is surely building on quicksand!

https://en.wikipedia.org/wiki/Bedford_Level_experiment
Rowbotham repeated his experiments several times over the years but his claims received little attention until, in 1870, a supporter by the name of John Hampden offered a wager that he could show, by repeating Rowbotham's experiment, that the earth was flat. The noted naturalist and qualified surveyor Alfred Russel Wallace accepted the wager. Wallace, by virtue of his surveyor's training and knowledge of physics, avoided the errors of the preceding experiments and won the bet. The crucial step was to set a sight line 13 feet (4 m) above the water, and thereby avoid the effects of atmospheric refraction. Despite Hampden initially refusing to accept the demonstration, Wallace was awarded the bet by the referee, editor of The Field sports magazine. Hampden subsequently published a pamphlet alleging that Wallace had cheated and sued for his money. Several protracted court cases ensued, with the result that Hampden was imprisoned for threatening to kill Wallace and for libel. The same court ruled that the wager had been invalid because Hampden retracted the bet and required that Wallace return the money to Hampden./quote]

Yes Hampden "won" the money, but with a reputation in shatters!

Look you have "a snowflakes chance in hell" of any wide acceptance till you have a model with:
an accurate map that can be used for find distances and directions accurately,
a model that can explain observed phenomena, sunrises, sunset etc.

Wallace and Hampden made a wager for a very large amount, equivalent to a year's worth of pay at that time. The results and controversies of that wager are invalid for that reason alone. It makes sense that either man would be untruthful if a year's wager was on the line. Wallace was a struggling author, and we can't put it past him to cheat over something that would ruin him.

[rabinoz]

Wallace and Hampden made a wager for a very large amount, equivalent to a year's worth of pay at that time. The results and controversies of that wager are invalid for that reason alone. It makes sense that either man would be untruthful if a year's wager was on the line. Wallace was a struggling author, and we can't put it past him to cheat over something that would ruin him.

Yes, but it was not just Wallace, he had other (hopefully) independent observers.

But, putting all that aside, the topic is "Geodetic Surveyor Straightens Out The Flat Earth Reality" and Geodetic Surveyors have been measuring the shape of the earth (size of degrees at various locations and the dimensions of continents and countries) for centuries. What I find amazing is the consistency achieved with (apparently) primitive equipment. You must have read of the detailed work involved in measuring long distances before electronic distance measuring equipment started being used, for the early Tellurometer (I remember using one as shown on the right[1]) to laser DME etc. Most importantly, the sizes and shapes measured by these older Geodetic Surveyors has not significantly changed since GPS has been used for location. So I see no reason to doubt the sizes of countries (or the sizes of degrees) given on maps such as Google Maps, Google Earth or those used on GPS navigators.

So if the actual dimensions of continents will not fit any of your flat earth models, you have considerable explaining to do! I can have some sympathy for Rowbotham, but mapping and our knowledge in general has progressed considerably since then.


[1]  I was trying to show students how they worked and how to used them - bit of blind leading the blind. You know what they say - if you can do, do, if you can't do, teach and if you can't even teach, you teach the teachers! I hope it was all in fun!

[Rama Set]

Wallace was a struggling author, and we can't put it past him to cheat over something that would ruin him.

But you also can't prove it.  A court of law found that Wallace had been slandered in this affair, which is the only substantiated viewpoint we can hold on to.  Your objection, while having some ethical validity does not have any grounding in reality.  When you can prove he cheated you should come to this.

[Tom Bishop]

It was a wager for money. The experiment is invalid for that reason alone. End of story.

[rabinoz]

It was a wager for money. The experiment is invalid for that reason alone. End of story.

So you will now omit all reference to the Bedford Canal experiment!
You do realise that even an atmospheric refraction of 0.5° can make an object at sea-level visible at 30 miles.
The only way to check this sort of thing is to do repeated measurements at various times of the day.
The images in this reference show what can happen http://www.atoptics.co.uk/fz904.htm.