[Max_Almond]

One thing we all seem able to agree on is that, in 2D images, parallel lines, when extended, appear to meet at the so-called 'vanishing point', and that the vanishing point corresponds to eye level.

A good way, therefore, to test whether eye level is at or above the horizon, is to gain some altitude, find some parallel lines, and use them to locate the vanishing point. Like this:



Or like this:



This is one very good way (of many) to find out for ourselves - using the zetetic method - whether eye level is at or above the horizon.

To do it yourself:

1. Find some parallel lines at least about 400 feet above a well defined horizon
2. Photograph them (in high resolution is better)
3. Draw along those lines sufficiently into the distance
4. See where they meet

[Bobby Shafto]

That's the principle behind this:

[Max_Almond]

You need to get that baby a coupla thousand feet up a mountain and put her to work!

[Bobby Shafto]

Not until I have clear sky on the horizon. Knowing Southern California climate, might not be until September.

[edby]

One thing we all seem able to agree on is that parallel lines meet at the so-called 'vanishing point', and that vanishing point corresponds to eye level.

Arggh. No I don't agree that parallel lines meet at any point. Lines of perspective meet, but these are projections of the parallel lines. Railway tracks are parallel, which is what keeps them on the tracks.

There is a serious point to this quibble. There is an idea that lines of perspective exist in reality, and that instead of meeting at infinity, they could meet earlier on. But they don't exist in reality, except as images.

[Max_Almond]

Okay. How about: "In 2D images, parallel lines, when extended, appear to meet at the vanishing point"?

[Curious Squirrel]

One thing we all seem able to agree on is that parallel lines meet at the so-called 'vanishing point', and that vanishing point corresponds to eye level.

Arggh. No I don't agree that parallel lines meet at any point. Lines of perspective meet, but these are projections of the parallel lines. Railway tracks are parallel, which is what keeps them on the tracks.

There is a serious point to this quibble. There is an idea that lines of perspective exist in reality, and that instead of meeting at infinity, they could meet earlier on. But they don't exist in reality, except as images.

Welcome to the foundation of perspective in the Flat Earth Hypothesis. That being, perspective is something all things experience, and parallel perspective lines meet significantly before infinity. I understand the oxymoron in that sentence, believe me. But this is why simply discussing this topic will never get anywhere. FE predicts that we will see almost exactly what RE predicts with respect to the horizon (I say almost, because clearly we have the whole 'horizon at eye level, but you're seeing how hard it is to prove this in any way shape or form) as well as most things we see. They claim why we see that is different, but you will never disabuse them of that idea.

[edby]

Okay. How about: "In 2D images, parallel lines, when extended, appear to meet at the vanishing point"?

Ok but I’m in an ultra-quibbly mood this evening. They don’t appear to meet, or converge at all. If so, you would be afraid ever to get on a train. Now they do actually meet in the retina (or rather converge, since the projection would only meet if the external lines went to infinity), or on drawings or photos etc. That’s all.

I say this because of something Tom said. I pointed out a good Youtube where the presenter explained perspective quite simply. Tom objected that this was only on paper, and proved nothing ‘about reality’. But of course it’s only on paper. That’s the only place where perspective lines exist. There is nothing remotely like that in reality. Otherwise, as I said, trains would rapidly derail, God forbid.

Sorry for the rant.

[Max_Almond]

No apology necessary: it's good to point these things out.

I'm thinking though, maybe it only needs one of "in a 2D image" or "appear to meet".

In a 2D image they do meet, as above.

What do you think?

[edby]

No apology necessary: it's good to point these things out.

I'm thinking though, maybe it only needs one of "in a 2D image" or "appear to meet".

In a 2D image they do meet, as above.

What do you think?

Yup.

[Max_Almond]

 

[Tom Bishop]

The distance is hazy and foggy in that image. How do you know that you are seeing the true horizon?

[Max_Almond]

The distance is hazy and foggy in that image. How do you know that you are seeing the true horizon?

Because I do.

Are you suggesting it's not?

[Tom Bishop]

The distance is hazy and foggy in that image. How do you know that you are seeing the true horizon?

Because I do.

Are you suggesting it's not?

At the altitude of an international flight the horizon is just a foggy mess. At lower altitudes, such as on the top of a sky scraper, what makes you think that the horizon isn't beginning its process of becoming a hazy mess, or that the horizon isn't dependent on the quality of the atmosphere in the far distance?

[Max_Almond]

Do you want me to tell you how to work it out? It'll involve some maths.

[Bobby Shafto]

The distance is hazy and foggy in that image. How do you know that you are seeing the true horizon?

How do you know you aren't?

How do you suggest determining whether or not a "true" horizon is being seen?

[Tontogary]

The distance is hazy and foggy in that image. How do you know that you are seeing the true horizon?

Because I do.

Are you suggesting it's not?

At the altitude of an international flight the horizon is just a foggy mess. At lower altitudes, such as on the top of a sky scraper, what makes you think that the horizon isn't beginning its process of becoming a hazy mess, or that the horizon isn't dependent on the quality of the atmosphere in the far distance?

Then at what height is it safe to use the visible horizon, as the actual horizon on a clear day?
 1 metre? 10Metres? 50Metres?

[AATW]

At the altitude of an international flight the horizon is just a foggy mess. At lower altitudes, such as on the top of a sky scraper, what makes you think that the horizon isn't beginning its process of becoming a hazy mess, or that the horizon isn't dependent on the quality of the atmosphere in the far distance?

*sigh*. I have explained this Tom. The horizon is further away the higher you go because you're looking over a curve, the higher you go the further over the curve you can see.
So yes, from a plane the horizon is so far away, and you're above clouds, that the horizon can be hard to see clearly. Even at ground level you can't see the horizon if it's foggy, it depends on visibility.
From a skyscraper on a clear day it's usually well defined enough as it is in that initial photo.
The idea that the land stops and the sky starts but actually the horizon is in the sky part is ludicrous.
As usual you're "doing a Rowbotham", looking at something which is very clear and, because it shows you to be wrong, pretending to see something else.
Dishonest.

[Tumeni]

At the altitude of an international flight the horizon is just a foggy mess.

Nice and clear at a few thousand miles up, though

[Max_Almond]

The distance is hazy and foggy in that image. How do you know that you are seeing the true horizon?

Because I do.

Are you suggesting it's not?

At the altitude of an international flight the horizon is just a foggy mess. At lower altitudes, such as on the top of a sky scraper, what makes you think that the horizon isn't beginning its process of becoming a hazy mess, or that the horizon isn't dependent on the quality of the atmosphere in the far distance?

Just to be clear, are you suggesting that the horizon is actually at eye level - ie, where the horizontal red line is - and that the only reason we can't see it is because of haze?