My impossible challenge for FE'ers

Quote from: JackBlack on October 02, 2022, 06:48:30 PM

A sufficiently small enough portion of a sufficiently large enough round surface will be indistinguishable from a flat surface.
If the curve is slight enough, you will not be able to detect it.

If you can't actually DETECT it, or SEE it, or MEASURE it, what does THAT tell you? Or SHOULD tell you? 

We do detect it, we do see it, we do measure it. You obviously have not been paying attention.

You don't understand that a curve, when it is small enough to NOT be seen, by human eye alone, is simply ONE factor of it, hardly the ONLY one, so don't play the fool, it won't work.

You are the one playing the fool here.
You are the one pretending that if a line is curved it must always be clearly curved, even if you see just a tiny portion of it.
That idea of yours is pure BS.

If you only see a small enough portion of a curve, you cannot tell if it is curved or straight.

This is a simple fact you refuse to accept.

Your two lines appear to be almost the same, almost straight, but measuring them, shows only ONE is straight

Pure BS.
The simplest way to see this is to just cut out the sections between the middle and edges of the image, and get this:


This shows the left hand side, the middle and the right hand side are identical.
You cannot measure the difference because the image is not accurate enough to do so.
The curve you need to see here is much less than 1 pixel.

The same issue occurs in reality, that issue you continually fled from as you were unable to provide a device that is capable of measuring a variation of 20 n, over a distance of 1 m.

The simple fact is that if you are looking at a small enough portion of a curve you cannot tell if it is curved or straight.
If you just measure the red line in the first image, you will not be able to measure the curve.

If you wish to spout such dishonest BS, then go and take that first image and show the measurement that allows you to determine the red line is curved.

it requires no zooming in to SEE a curve is there, or not there at all.

Saying this just shows you either have no idea what you are talking about, or you are intentionally spouting pure BS.

The point is that if you only see a tiny portion you can't tell. In order to tell you need to see more, you need to zoom out.

You tried to show both lines overlapping each other, not as two separate lines - get serious!

Follow your own advice.
I showed the 2 overlapping to show just how similar they look. Unless you had another image to compare with, you would not be able to tell which is straight and which is curved.

Now again, how about you stop with the pathetic deflection and explain how perspective magically stops and reverse to produce a horizon on a flat surface.
Don't just repeatedly assert that it magically does. Clearly explain how.

Whenever we observe a surface which we can confirm to be flat, we see across the entire surface when above it. We do not get any magical horizon.

What confirms that a surface IS flat, specifically?

Since you believe we CAN confirm a surface is flat, how do we KNOW that it is flat?

Quote from: JackBlack on October 07, 2022, 07:40:34 PM

Whenever we observe a surface which we can confirm to be flat, we see across the entire surface when above it. We do not get any magical horizon.

What confirms that a surface IS flat, specifically?

Since you believe we CAN confirm a surface is flat, how do we KNOW that it is flat?

Technically we know all surfaces are not perfectly flat, and instead are flat to within some tolerance.
We determine that by measuring across the ENTIRE surface.

Note the important part, we don't just measure a tiny portion, and then say the entire surface is flat.
We measure across a decent sampling of the entire surface.
e.g. for a table, you measure along gridlines for a grid spanning the entire surface.

And importantly, you understand how the accuracy and precision of your tool will affect the accuracy and precision of the overall result.
And the best measurements will often use a reference flat surface.

These reference flat surfaces, if they are small enough, can be created as a group of 3 surfaces, where each surface is within a certain variation (dependant on how accurate you want your reference flat to be) of mating with each of the other 2 surface.

Now again, how about you stop with the pathetic deflection and explain how perspective magically stops and reverse to produce a horizon on a flat surface.
Don't just repeatedly assert that it magically does. Clearly explain how.

Technically we know all surfaces are not perfectly flat, and instead are flat to within some tolerance.
We determine that by measuring across the ENTIRE surface.

Note the important part, we don't just measure a tiny portion, and then say the entire surface is flat.
We measure across a decent sampling of the entire surface.
e.g. for a table, you measure along gridlines for a grid spanning the entire surface.

And importantly, you understand how the accuracy and precision of your tool will affect the accuracy and precision of the overall result.
And the best measurements will often use a reference flat surface.

These reference flat surfaces, if they are small enough, can be created as a group of 3 surfaces, where each surface is within a certain variation (dependant on how accurate you want your reference flat to be) of mating with each of the other 2 surface.

And surveyors on projects would measure an entire area, assuming it IS flat, measuring where it IS flat, and where it is NOT flat, right?

If you say that we can confirm a surface is flat, by measuring the whole area, why do you claim that we cannot confirm a surface is CURVED, the very same way? We can and do measure a curved surface, a flat surface, or ANY surface, in fact. 

The official claim that they always 'assume' the surface is flat, while they use precise instruments that MEASURE the whole surface, and any areas NOT flat, and account for it, as NOT flat, is clear proof that they KNOW it IS flat, MEASURE it as flat, and is why they 'assume' it is flat, on ALL projects, BEFORE they even begin them at all.

If 'curvature' DID exist, over the whole surface of Earth, surveyors would always assume the surface IS curved, at a specific rate of curvature over each area they survey for projects, that would be common practice, and common sense to do. What the hell do you think they're DOING here? The REAL surface, with REAL instruments, with as MUCH accuracy as possible. They aren't idiots, saying 'Well, we can just ASSUME it's flat, even if it's NOT flat, and then measure it, accurately, or close enough anyhoo!'

You'll believe whatever they tell you, is all true.

And surveyors on projects would measure an entire area, assuming it IS flat, measuring where it IS flat, and where it is NOT flat, right?

Again, this comes down to TOLERANCES! Something you continually want to ignore.
No measurement is perfect. All measurements will have some degree of uncertainty.
Likewise, no produced material will be perfect, they will all have some level of variation.

For most projects, the variation of the materials will be far more significant than the curvature due to earth.

If you say that we can confirm a surface is flat, by measuring the whole area, why do you claim that we cannot confirm a surface is CURVED, the very same way?

We can, and we have measured Earth's surface and found it to be curved.
You don't like that because you can't see the curve over 1 m.

The official claim that they always 'assume' the surface is flat

No, that is not an official claim. That is your claim.

they use precise instruments that MEASURE the whole surface

You really do love showing that you are desperate don't you?
Are you saying to build a house on one small block, they would measure the entirety of Earth?
That is insanity.

If 'curvature' DID exist, over the whole surface of Earth, surveyors would always assume the surface IS curved

Stop spouting the same refuted BS.

For most applications, the curvature is insignificant and does not need to be accounted for. All using curvature would do here is complicate the math.
There is no need for it, so they wont.

The REAL surface, with REAL instruments, with as MUCH accuracy as possible.

Now, by this do you actually mean accuracy, or do you mean precision? The 2 are different.

I could say the curvature of Earth is 0 with a margin of error of 1 /m.
That would technically be accurate, as I have included the range, but it is not precise.

Regardless, you are wrong.
Only in science, where they care about discovering how the world works, do they go for as accurate and precise as possible.
For engineering, they go for as accurate and precise as needed/practical.

They are quite happy to use tools which are imprecise, which cannot measure the curvature of Earth, because it isn't needed.

They aren't idiots. They aren't going to waste millions or billions of dollars on something that will be pointless due to the variance in materials.

You'll believe whatever they tell you, is all true.

No, I believe what is supported by the evidence, and makes logical sense.

Your delusional BS does not fit either criteria.
You baselessly assert that they would try to measure it as accurately as possible, with no justification at all, nor any evidence to support that fantasy of yours.
All for the implication that they should be measuring the curvature of Earth and accounting for it. All without even bothering with a simple bit of math to show how significant it should be.

Here is some simple math for you. Lets say we are building a skyscraper.
It can be 100 m tall, and have a base of 100 m.
That means from the centre out, there would be a drop due to a distance of 50 m. That is a drop of 0.196 mm.
As a comparison, consider a 25 mm by 25 mm area of concrete from here:
https://www.concreteconstruction.net/business/surface-roughness-of-concrete_o
The average surface roughness was 0.1259 mm, and the total height variation was 2.047 mm.

That means the average roughness is comparable to the drop, and the total height variation was roughly 10 times the expected drop.
Why would they bother with the drop due to the curvature of Earth when concrete would produce a larger variation?

As the edges of the building are 100 m apart, that means they are an angle of 3.2 arc seconds different.
The 100 m of height, with this angle, will make the top of the building (which would typically be much smaller than the base, buts lets ignore that for now) 1.6 mm wider, if they construct the building entirely plumb. It could be 0 if the walls are angled just a tiny bit (1.6 arc seconds each, which is already an incredibly small angle).
But again appealing to real materials, lets look at thermal expansion:
https://www.engineeringtoolbox.com/linear-expansion-coefficients-d_95.html
Concrete has a coefficient of thermal expansion of 13-14 *10^-6 (or a structure is 9.8*10^-6).
For simplicity lets use a value of 10*10^-6 = 10^-5.
That means for each 1 degree celsius rise in temperature, our 100 m wide structure would expand (or contract) roughly 1 mm.
So if the temperature fluctuates by 10 degrees, it would amount to a change of 10 mm. Already over 5 times that due to the curvature.

So with the curvature having such a minor effect, why should they account for it?


And unlike you, I don't need to lie and claim all the evidence is fake, or continually deflect by jumping topics.

Now again, how about you stop with the pathetic deflection and explain how perspective magically stops and reverse to produce a horizon on a flat surface.
Don't just repeatedly assert that it magically does. Clearly explain how.

Or does your repeated refusal to do so amount to an admission that you cannot explain it and that the fact that objects appear to sink as they go beyond the horizon is a clear demonstration that Earth is curved?

And surveyors on projects would measure an entire area, assuming it IS flat, measuring where it IS flat, and where it is NOT flat, right?

Utah GEODETIC Surveying
Geodetic surveying is similar to other types of land surveying, except that it takes into account the curvature of the Earth. Geodetic surveys generally take part over large areas, and provide great accuracy in both the linear and angular observations. a Geodetic survey takes two points located on the Earth's surface and treats them as arcs; the curvature of the Earth is then taken into account, and the angles between the lines help determine the distance between the two points. These surveys are often used to retrace the public land survey system, and replace or modify missing corners if necessary.

Quote from: JackBlack on October 07, 2022, 11:39:17 PM

Technically we know all surfaces are not perfectly flat, and instead are flat to within some tolerance.
We determine that by measuring across the ENTIRE surface.

Note the important part, we don't just measure a tiny portion, and then say the entire surface is flat.
We measure across a decent sampling of the entire surface.
e.g. for a table, you measure along gridlines for a grid spanning the entire surface.

And importantly, you understand how the accuracy and precision of your tool will affect the accuracy and precision of the overall result.
And the best measurements will often use a reference flat surface.

These reference flat surfaces, if they are small enough, can be created as a group of 3 surfaces, where each surface is within a certain variation (dependant on how accurate you want your reference flat to be) of mating with each of the other 2 surface.

And surveyors on projects would measure an entire area, assuming it IS flat, measuring where it IS flat, and where it is NOT flat, right?

If you say that we can confirm a surface is flat, by measuring the whole area, why do you claim that we cannot confirm a surface is CURVED, the very same way? We can and do measure a curved surface, a flat surface, or ANY surface, in fact. 

The official claim that they always 'assume' the surface is flat, while they use precise instruments that MEASURE the whole surface, and any areas NOT flat, and account for it, as NOT flat, is clear proof that they KNOW it IS flat, MEASURE it as flat, and is why they 'assume' it is flat, on ALL projects, BEFORE they even begin them at all.

If 'curvature' DID exist, over the whole surface of Earth, surveyors would always assume the surface IS curved, at a specific rate of curvature over each area they survey for projects, that would be common practice, and common sense to do. What the hell do you think they're DOING here? The REAL surface, with REAL instruments, with as MUCH accuracy as possible. They aren't idiots, saying 'Well, we can just ASSUME it's flat, even if it's NOT flat, and then measure it, accurately, or close enough anyhoo!'

You'll believe whatever they tell you, is all true.

Practically speaking then, what is the angle between segments of a 300,000sided polygon?

Quote from: JackBlack on October 07, 2022, 11:39:17 PM

Technically we know all surfaces are not perfectly flat, and instead are flat to within some tolerance.
We determine that by measuring across the ENTIRE surface.

Note the important part, we don't just measure a tiny portion, and then say the entire surface is flat.
We measure across a decent sampling of the entire surface.
e.g. for a table, you measure along gridlines for a grid spanning the entire surface.

And importantly, you understand how the accuracy and precision of your tool will affect the accuracy and precision of the overall result.
And the best measurements will often use a reference flat surface.

These reference flat surfaces, if they are small enough, can be created as a group of 3 surfaces, where each surface is within a certain variation (dependant on how accurate you want your reference flat to be) of mating with each of the other 2 surface.

And surveyors on projects would measure an entire area, assuming it IS flat, measuring where it IS flat, and where it is NOT flat, right?

If you say that we can confirm a surface is flat, by measuring the whole area, why do you claim that we cannot confirm a surface is CURVED, the very same way? We can and do measure a curved surface, a flat surface, or ANY surface, in fact. 

The official claim that they always 'assume' the surface is flat, while they use precise instruments that MEASURE the whole surface, and any areas NOT flat, and account for it, as NOT flat, is clear proof that they KNOW it IS flat, MEASURE it as flat, and is why they 'assume' it is flat, on ALL projects, BEFORE they even begin them at all.

If 'curvature' DID exist, over the whole surface of Earth, surveyors would always assume the surface IS curved, at a specific rate of curvature over each area they survey for projects, that would be common practice, and common sense to do. What the hell do you think they're DOING here? The REAL surface, with REAL instruments, with as MUCH accuracy as possible. They aren't idiots, saying 'Well, we can just ASSUME it's flat, even if it's NOT flat, and then measure it, accurately, or close enough anyhoo!'

You'll believe whatever they tell you, is all true.

It's not practical to factor in curvature over small distances, but build a long tunnel or long bridge and you'll have to pull out your curvature measuring devices.

Quote from: turbonium2 on October 08, 2022, 12:32:19 AM

Quote from: JackBlack on October 07, 2022, 11:39:17 PM

Technically we know all surfaces are not perfectly flat, and instead are flat to within some tolerance.
We determine that by measuring across the ENTIRE surface.

Note the important part, we don't just measure a tiny portion, and then say the entire surface is flat.
We measure across a decent sampling of the entire surface.
e.g. for a table, you measure along gridlines for a grid spanning the entire surface.

And importantly, you understand how the accuracy and precision of your tool will affect the accuracy and precision of the overall result.
And the best measurements will often use a reference flat surface.

These reference flat surfaces, if they are small enough, can be created as a group of 3 surfaces, where each surface is within a certain variation (dependant on how accurate you want your reference flat to be) of mating with each of the other 2 surface.

And surveyors on projects would measure an entire area, assuming it IS flat, measuring where it IS flat, and where it is NOT flat, right?

If you say that we can confirm a surface is flat, by measuring the whole area, why do you claim that we cannot confirm a surface is CURVED, the very same way? We can and do measure a curved surface, a flat surface, or ANY surface, in fact. 

The official claim that they always 'assume' the surface is flat, while they use precise instruments that MEASURE the whole surface, and any areas NOT flat, and account for it, as NOT flat, is clear proof that they KNOW it IS flat, MEASURE it as flat, and is why they 'assume' it is flat, on ALL projects, BEFORE they even begin them at all.

If 'curvature' DID exist, over the whole surface of Earth, surveyors would always assume the surface IS curved, at a specific rate of curvature over each area they survey for projects, that would be common practice, and common sense to do. What the hell do you think they're DOING here? The REAL surface, with REAL instruments, with as MUCH accuracy as possible. They aren't idiots, saying 'Well, we can just ASSUME it's flat, even if it's NOT flat, and then measure it, accurately, or close enough anyhoo!'

You'll believe whatever they tell you, is all true.

Practically speaking then, what is the angle between segments of a 300,000sided polygon?

If you can't answer your own question, or make a point about it, nobody here is going to help you, including me. You should know that by now.

If you can't answer your own question, or make a point about it, nobody here is going to help you, including me. You should know that by now.

It has been answered, with the point made from it being repeatedly ignored by you, with you sometimes just outright lying by ignoring the answer.

The point is that due to how large Earth is, you cannot measure the curvature over a tiny portion of it.
For Earth, with a radius of roughly 40 000 km, a 300 000 sided polygon would correspond to roughly 133 m.
And the exterior angle of an n sided polygon is 360 degrees/n, which for this gives us 0.0012 degrees.


If you had an object 133 m away, standing upright at its location, then relative to you standing upright at your location, it would have tilted back 0.0012 degrees.

This shows just how tiny the curvature is, and why you don't need to care about it for most construction projects, and why you wont see obvious curvature just by looking at the ground at your feet.

You say Earth looks flat, because you cannot detect such a tiny change.


Also, have you considered following your own advice?
How many times have you suggested we do something to try to prove your point, while refusing to do it yourself (likely because you know it will refute you).

Again, this comes down to TOLERANCES! Something you continually want to ignore.
No measurement is perfect. All measurements will have some degree of uncertainty.
Likewise, no produced material will be perfect, they will all have some level of variation.

For most projects, the variation of the materials will be far more significant than the curvature due to earth.

That doesn't mean we cannot MEASURE it as flat, OR as 'curved', within allowable tolerances, that's the point here.

If a surface 500 feet long, 400 feet wide, is measured as flat, within allowable tolerances, the same works with LONGER areas, and their relative tolerances, right?

The first area measures flat, within acceptable tolerances. An adjacent area measures flat, within tolerances. And a third area, adjacent to the second one, also measures flat, within tolerances.

Each of those 3 areas are measured flat, so to know if all 3 areas TOGETHER are flat, there's several ways to confirm it, and make sure all of them, separately, OR collectively, are flat.

Even using the same 3 areas, we can find out if all 3 are flat, as one combined area. We can overlap half the first area, and half the second area, and measure it, to confirm each half remains flat, and repeat this over and over again, in different sections.

We can easily do this to measure for your supposed 'curvature' of Earth, too.

You believe that Earth has a 'curvature' of about 8 inches per mile, squared each additional mile. And you also claim we cannot MEASURE for it, within such 'small' areas, and we don't have instruments which can detect it, over those 'small' areas.

Everything seems so 'small', it's almost like it doesn't even EXIST AT ALL!  There's no indication it actually DOES exist, nothing measures for it, nothing seen of it, anywhere at all, on or above the Earth.

It's purely a fairy tale, a fable, created by liars.

It's purely a fairy tale, a fable, created by liars.

Airline pilots are liars?

That doesn't mean we cannot MEASURE it as flat, OR as 'curved', within allowable tolerances, that's the point here.

The point is that you are ignoring those tolerances.
The point is that you are measuring it as "flat" with tolerances that cannot tell if it is a sphere of radius 6371 km, i.e. you cannot tell if Earth overall is flat or round.

Understand yet?

You trying to measure Earth's surface, over a distance of 1 m, to assert the RE model is wrong, is entirely pointless unless you are capable of measuring a variation of 20 nm over this distance of 1 m.

Yet you want to pretend that because you can't detect that tiny variation, that the RE model is wrong.

You want to pretend that a curve will always be easily and clearly visible as a curve, which is to completely ignore those facts about tolerances.
Those tolerances mean that if the curve is large enough such that the curvature is small enough, you cannot tell if it is curved or flat.

If a surface 500 feet long, 400 feet wide, is measured as flat, within allowable tolerances, the same works with LONGER areas, and their relative tolerances, right?

If you actually measure it to those tolerances, or understand how to combine those tolerances/uncertainties to get the overall uncertainty/tolerance.
You can't just say an area is flat to within 1 mm over a distance of 1 m so it must be flat to within 1 mm over 100 km.

Even using the same 3 areas, we can find out if all 3 are flat, as one combined area. We can overlap half the first area, and half the second area, and measure it, to confirm each half remains flat, and repeat this over and over again, in different sections.

This doesn't show what you think it does.
Again, this is directly where that question of a 300 sided polygon comes in.

Lets say you have an area that is 100 m wide. You measure it and deem it to be "flat", but the uncertainty of your measurement is 0.1 degrees.
That is your measurement is only capable of determining that one side of this area is within 0.1 degree, up or down, of the other side (in fact that would apply to the entire area).
It doesn't matter how many of these 100 m wide areas you measure, nor how many times you measure it, nor how much overlap you have. All you will do with that is confirm that that span is within that tolerance.

To actually combine it, lets say you take 2 100 m wide areas, side by side. The expanded uncertainty becomes 0.2 degrees.
After 10 such measurements you are up to an uncertainty of 1 degree.
After 3600 such measurements you are up to an uncertainty of 360 degrees.
That means after 360 km, you have no idea what the orientation of the surface is relative to the first point.

That means you have no idea if that 360 km span is entirely flat, or a curved into a circle. (Well technically you can figure out it isn't a circle by realising you aren't back where you started).

Everything seems so 'small', it's almost like it doesn't even EXIST AT ALL!  There's no indication it actually DOES exist, nothing measures for it, nothing seen of it, anywhere at all, on or above the Earth.

Stop repeating the same refuted BS.
You can't measure it over a tiny area like you want to.
But over a large enough area you can. It is measured, it is seen, repeatedly.

Again, the very topic you continue to avoid shows it is round.
The mere existence of the horizon should be a dead give away. A flat surface only has a horizon at the edge.
But a curved surface will have a horizon where a line from your eye goes tangent to the curve.
This means the horizon on a curved surface will move with you and be dependent upon your distance from it.
This matches what is observed for Earth in reality, a horizon that moves with you and is dependent upon your altitude/height.

Likewise, as an object goes into the distance on a flat surface, it remains entirely visible, never appearing to sink.
But on a curved surface, after enough distance the horizon and the curved surface start to obstruct the view. This causes the object to appear to sink and disappear from the bottom up.
Again, this is observed.

You can directly measure the dip angle to the horizon, and with knowledge of your altitude, you can use that measurement to calculate the radius of Earth.
You can measure the direction and distance along large roads or large maps, and try plotting them on a flat surface and seeing that it doesn't work, and then try on a round surface and adjusting the radius until it does fit.

You can also see its effects by looking at the stars or celestial objects.
We can look at the moon and observe the same face (roughly) from all over Earth. Likewise, we can observe the constellations, looking the same (if visible) all over Earth.
There is no apparent distortion which would be expected if you were looking at it from a different angle, nor do we see a significantly different face.
This means they must be in the same direction for everyone. But their apparent direction (i.e. the direction relative to the surface of Earth at your location) varies. That means the orientation of Earth itself must vary.
And if you measure how this varies, you see that Earth is round.

We can also use a ring laser gyroscope or Foucault's pendulum, to measure the rotation of Earth.
A ring laser gyro is better because it can measure the angle of the axis, instead of needing to just observe that the apparent period changes as you do with Foucault's pendulum.
You can then see how this axis or period varies across Earth, and see how well that fits a RE, and how it doesn't fit a flat Earth at all.

So again, your claim is pure BS.
There is plenty of indication that Earth is curved. Plenty measures for it, and plenty is seen of it.

This not happening over a tiny area doesn't mean it doesn't happen over a much larger area.

Stop pretending not being able to measure the curve over 1 m means it isn't curved at all.
Stop with all these pathetic deflections, and trying addressing the issue at hand.

Again, what magic magically causes perspective to magically stop and reverse to cause a flat surface below you to stop "appearing to rise" and instead make objects more distance appear to have sunk and have the lower portion obstructed from view?

If you can't, then why don't you be honest, admit you can't, and admit that this phenomenon is evidence for the curvature of Earth?

The point is that due to how large Earth is, you cannot measure the curvature over a tiny portion of it.

We certainly CAN measure for a 'curve', within a micron, by simply using the proper INSTRUMENTS!

I've heard over and over, that we cannot use a LASER level, to measure for 'curvature', which is complete BS.

It can easily be measured, using an accurate laser level, at it's minimum variance, which will be a certain maximum distance.

What your side does, is assume it must measure over a LONG distance, which is BS. It only has to measure what it CAN accurately measure, and nothing BEYOND what it can accurately measure.

Use your brain for once. The instruments which measure for level, do NOT measure for any sort of 'curve', or any sort of 'curvature' on Earth, but only because it does not EXIST on the Earth's surface, NOT because we COULDN'T measure for it, since we certainly can, and would be able to measure for it, and already WOULD have measured it, years ago, and would today, even MORE accurately than before.

The best laser levels we have today, can easily, accurately, measure a flat line over a mile, in excellent conditions, but let's say it is most accurate, up to a HALF mile, or up to a QUARTER mile.

That is the ONLY distance which matters, to prove no 'curve' exists.

There's several methods we can use, to measure for 'curvature', your excuse that it is 'too slight a curve to measure for it', assumes that we must measure for it, as a single area, with a single measurement of that area, and even though we CAN measure for it over such an area, with instruments of today, I'm going to explain how we can measure it with laser levels, easily.

Do you recall the experiment where they claimed that a laser level didn't measure accurately over a certain distance, so they used 'light beams' instead, and claimed it proved there WAS 'curvature'? I'm sure you do.

What they DIDN'T say, and DIDN'T do, is use their laser level, up to it's OPTIMUM distance for accuracy, to make it FAR MORE ACCURATE than any 'light beam' comes CLOSE to being!

Using several of the same laser levels, each one placed within range of the other ones, or using just ONE level, and marking each point along the distance, will prove if there is 'curvature' or not, so why hasn't anyone DONE it yet? Maybe it has been done, who knows?

We could set up two or three lines with laser levels, at different points, to confirm our findings.

It could be done in much smaller sections, for more accurate measurements, too.

But don't tell me it's not possible to MEASURE for it, because that's complete BS, and you know it.

 

Quote from: JackBlack on October 08, 2022, 08:57:25 PM

The point is that due to how large Earth is, you cannot measure the curvature over a tiny portion of it.

We certainly CAN measure for a 'curve', within a micron, by simply using the proper INSTRUMENTS!

How might you go about doing that?

Please describe the steps in detail and the proper instruments required.

We certainly CAN measure for a 'curve', within a micron, by simply using the proper INSTRUMENTS!

Over a small distance, sure. But over that small distance you need to measure a variation of 10s of nm to measure the curve of Earth, so no, you can't.

Over a long enough distance, we can easily measure it with a theodolite, as people have.
Even the FE high prophet Row Boat somewhat accepts that, but he then demands making the apparatus much worse by removing the lens to pretend it can't.

I've heard over and over, that we cannot use a LASER level, to measure for 'curvature', which is complete BS.

And as I have said over and over, you not liking reality doesn't make it BS.

Use your brain for once. The instruments which measure for level, do NOT measure for any sort of 'curve', or any sort of 'curvature' on Earth, but only because it does not EXIST on the Earth's surface

Follow your own advice.
As I have demonstrated, the curvature is insignificant at small distances, so there is no need to correct for it, and it almost certainly cannot be measured for over such small distances.

If you wish to disagree, then stop just asserting BS and start justifying your claims.
Prove that such a variation can be measured for over a short distance, and stop ignoring all the measurements of curvature over a long distance.

The best laser levels we have today, can easily, accurately, measure a flat line over a mile, in excellent conditions, but let's say it is most accurate, up to a HALF mile, or up to a QUARTER mile.

Your statement is meaningless.
"measure a flat line" tells us nothing about just how flat it is.
It does nothing to show if it can measure the curvature of Earth.

If you want to assert it can measure for the curvature of Earth, then provide the specifications with a reference.
If you can't do that, then stop with the BS.
And regardless of which path you take, stop just saying it can measure flat, without any specification of uncertainty.

There's several methods we can use, to measure for 'curvature', your excuse that it is 'too slight a curve to measure for it', assumes that we must measure for it, as a single area, with a single measurement of that area

No it doesn't, but as already explained, if you want to try combining measurements, then you need to understand how that impacts uncertainty.
Again, this is where a 300 000 sided polygon comes in. If you can only measure a variation of 0.1 degree, then you would measure each corner as "straight", and thus falsely conclude this 300 000 sided polygon is a straight line.
Conversely, I recognise the limitation of the measuring device and how the uncertainty combines to realise that by the 3600th corner, we have no idea what the orientation of the next side is compared to the first side.

You can't even just use height like you want to. A laser level, if set up well, will level itself. That means if there is a curve, they will be offset at an angle. And so if you can't measure the curvature with one length, you wont be able to do so with 2.

Do you recall the experiment where they claimed that a laser level didn't measure accurately over a certain distance, so they used 'light beams' instead, and claimed it proved there WAS 'curvature'? I'm sure you do.

No, I have no idea what you are talking about.

Using several of the same laser levels, each one placed within range of the other ones, or using just ONE level, and marking each point along the distance, will prove if there is 'curvature' or not, so why hasn't anyone DONE it yet? Maybe it has been done, who knows?

Maybe because they aren't accurate enough to do so.

It could be done in much smaller sections, for more accurate measurements, too.

While each individual measurement will be more accurate, the overall measurement will not.

But don't tell me it's not possible to MEASURE for it, because that's complete BS, and you know it.

Again, it is possible to measure for the curvature, it has been done.
What I will continue to tell you is the truth, that it is impossible to measure it over a very small distance, because we do not have the tools that are accurate enough to measure such a variation over such a small distance.

Again, if you wish to disagree, then instead of spouting pure BS, justify it. Provide the specifications of a device to show it CAN measure the curvature, and provide a reference to those specs.

If you would like an example of how to do that:
Here is a page discussing laser levels:
https://www.topconlaser.com.au/accuracy_laser_levels
It claims the most accurate laser level is accurate to 1.5 mm at 30 m. (This is an angle of 10.3 arc seconds).

Using these 30 m, and the simple approximation of h=d^2/(2R) we get the drop due to the curvature over that distance of 30 m is 0.07 mm. Less than one 20th of the uncertainty. So it certainly can't measure it at that distance.
Now sure, you can try going out more, but how accurate is it then, and can it even reach?

You would need a distance of 637.1 m to have the uncertainty match the drop due to curvature.
But according to the brochure:
https://d3r4tb575cotg3.cloudfront.net/static/topcon_518668_rl-h5a_brochure_a_team_en_us_low_reseller.pdf
It has a range of 400 m.

If we put in those 400 m we get an uncertainty of 19.4 mm using the 10 arcseconds, or 20 mm using the 1.5 mm per 30 m. But we get a drop due to curvature of 12.6 mm. Notice how the drop is less than the uncertainty.

So it appears this laser level, described as the most accurate, is unable to measure the curvature.


And again, what magic magically causes perspective to magically stop and reverse to cause a flat surface below you to stop "appearing to rise" and instead make objects more distance appear to have sunk and have the lower portion obstructed from view?

If you can't tell us, then why don't you be honest, admit you can't, and admit that this phenomenon is evidence for the curvature of Earth?

The Leica DISTO D2 is 1/16-inch accurate to a distance of 328 feet.

The surface used for this test, is a perfectly calm lake, without any winds to cause a disturbance over the lake surface. I've seen a local lake in early morning, and it looks like glass, it is so smooth and flat. That's what is ideal for such tests.

The lake should ideally be at least 2-3 miles in length, or longer than that, also.

Our laser level is placed at a specific height above the lake, along it's edge, pointed outward over it. A target is placed about 300 feet out, marked in inches, and fractions, on one side, and in cm and mm on the other side, like a ruler. It must remain steady, as a gauge. Other gauges placed nearby, would help to confirm it is accurate.

One mile is 5280 feet. Our first target is 300 feet away, or about 1/17.5 of a mile. 

And then, we repeat the test, from the first target, to a second target, 300 feet away from it, and so on, over a mile distance on the lake.

With 17 points used in this test, and each point having 1/16 accuracy variance, the total combined variance would be about one inch, and a bit more, over one mile distance. That is the maximum variance, it could be less than that, too.

With a one inch variance, over one mile of distance, there would be about 8 inches of 'curvature', if it DID exist, and WOULD be measured, with this test, if it is actually there TO be measured.

Of course, we would repeat this test, several times, to confirm our findings. 



To claim your 'curvature' is 'too slight' to be measured, is nothing but a lame excuse. It is EASILY measured, and in many, many more ways than the one I've mentioned here.

 

The Leica DISTO D2 is 1/16-inch accurate to a distance of 328 feet.

The surface used for this test, is a perfectly calm lake, without any winds to cause a disturbance over the lake surface. I've seen a local lake in early morning, and it looks like glass, it is so smooth and flat. That's what is ideal for such tests.

The lake should ideally be at least 2-3 miles in length, or longer than that, also.

Our laser level is placed at a specific height above the lake, along it's edge, pointed outward over it. A target is placed about 300 feet out, marked in inches, and fractions, on one side, and in cm and mm on the other side, like a ruler. It must remain steady, as a gauge. Other gauges placed nearby, would help to confirm it is accurate.

One mile is 5280 feet. Our first target is 300 feet away, or about 1/17.5 of a mile. 

And then, we repeat the test, from the first target, to a second target, 300 feet away from it, and so on, over a mile distance on the lake.

With 17 points used in this test, and each point having 1/16 accuracy variance, the total combined variance would be about one inch, and a bit more, over one mile distance. That is the maximum variance, it could be less than that, too.

With a one inch variance, over one mile of distance, there would be about 8 inches of 'curvature', if it DID exist, and WOULD be measured, with this test, if it is actually there TO be measured.

Of course, we would repeat this test, several times, to confirm our findings. 



To claim your 'curvature' is 'too slight' to be measured, is nothing but a lame excuse. It is EASILY measured, and in many, many more ways than the one I've mentioned here.

Why bother.  You already ignore this…

Shrugs…

Power lines over Lake Pontchartrain elegantly demonstrate the curvature of Earth

https://www.zmescience.com/science/news-science/power-lines-curvature-earth-04233/amp/

And you ignored this too.

And the Rainy Lake Experiment.

Proof of Earth Curvature: The Rainy Lake Experiment

http://walter.bislins.ch/bloge/index.asp?page=Proof+of+Earth+Curvature%3A+The+Rainy+Lake+Experiment

Both that don’t require the impossible calmness between there is always air currents, differences in temperature, biologics splashing around, the wake of boats, and tides.  Measurements at the edge of a instruments tolerances.

And this has been cited for you too…

There is one huge towing tank of about 500m, so long that the tank has been built following the Earth curvature - as the water surface would do - and not straight to avoid vertical position offset of models under test (about 18 cm). The second towing tank is shorter (about 220m) but it can generate controlled waves to analyze hull behavior at difference sea force levels.

https://dewesoft.com/case-studies/naval-and-marine-performance-testing-and-simulation

The Leica DISTO D2 is 1/16-inch accurate to a distance of 328 feet.

Do you understand what a REFERENCE is?
You are just asserting that it is accurate with no justification of that claim, nor any simple way to verify it.

A quick search finds this:
https://shop.leica-geosystems.com/au/buy/disto/d2

It is a distance measurement device, not a level.
That means it is entirely in appropriate for your suggested test, as it is not the correct device.

Do you even understand the difference between the 2?

Even if I were to accept your fantasy where it can magically switch to a laser level, it is accurate to 1.5 mm with a range of 100 m.
But the drop due to curvature over that range is 0.78 mm. That is roughly half the accuracy of the device, so it can't measure the curve.

With 17 points used in this test, and each point having 1/16 accuracy variance, the total combined variance would be about one inch, and a bit more, over one mile distance. That is the maximum variance, it could be less than that, too.

No, it isn't. That isn't how it works at all.
You are looking at the uncertainty for the measurement, while ignoring the uncertainty of the alignment.

That would be like suggesting I can take a 10 cm ruler, and measure from the start of a 1 m long object to the first 10 cm, put my finger down to mark that position and then move the ruler along, and repeat until I measure the entire object, then claiming that because the ruler is accurate to less than 1 mm, the overall result must be accurate to less than 1 cm. The problem is this ignores the issue of alignment.
Each time the rule is moved, there is an uncertainty associated with the alignment, which is separate from the uncertainty in the measuring device.

That can make the overall uncertainty much larger.

So just how are you aligning your device?
If we assume that it is a level, instead of a distance meter, and assume it will level itself, then if Earth is flat, such that level is the same everywhere, then it would be simple like you have done. But in reality, with a curved Earth, you are measuring different orientations, and you need to account for that change in orientation when combining your measurement.

Here is an example of an extreme case, drawn using different numbers, but drawn to scale:

We see that the measurement has un uncertainty of 0.01 over the distance 0.1.
But when we take our second point, Earth has curved, so it levels to a different orientation. This means our overall uncertainty is no longer simple addition, even though the second measurement also has an uncertainty of 0.01 over a distance of 0.1.
Instead, the uncertainty is a combination of the individual measurement uncertainties and the alignment uncertainty. This results in an overall result of an error 0.038 over a distance of 0.197. Not the 0.02 error over a distance of 0.2 like you want to pretend.

So no, your method does not work, or at best, is entirely circular, assuming Earth is flat to assert the alignment is the same in each case to then claim you don't measure the curvature expected for a RE so Earth is flat.
But it is only by already assuming your conclusion that Earth is flat that you reach the result that Earth is flat.

Without that baseless (and false) assumption, you have no idea what the alignment is, and thus no idea what the overall uncertainty is.
Without that baseless (and false) assumption, Earth could be (and is) round, and thus the alignment can be different for each measurement, increasing the overall uncertainty allowing the curvature of Earth to sit entirely inside that uncertainty.

So unless you can use a laser level (not distance measurement tool), and describe the alignment procedure and the associated uncertainty with that procedure, your test is entirely useless.

And once all that is dealt with, you then get to deal with the surface of the lake.
What is the uncertainty in the surface of the lake? If the lake's surface varies by a cm, then that will be an additional variation which needs to be accounted for which will expand the uncertainty in the overall result.

To claim your 'curvature' is 'too slight' to be measured, is nothing but a lame excuse. It is EASILY measured, and in many, many more ways than the one I've mentioned here.

Again, the curvature can and has been measured. It just can't be measured by a laser level (and certainly not by a laser distance measurement device) over a small area.

No, it is accurate to 1/4 inch over 300 feet, and 1/4  inch accurate over the next 300 feet, and so on, and to confirm those measurements are valid, over each section, as constant throughout them all, we use a second line of measurements, halfway up the first sections, to account for any error in each transition point, if any are found.

A third set of measurements halfway up from the second one, can further confirm those points of transition, too.

Our goal is to measure for the whole surface, by measuring a part of it, over and over again, which is confirmed by another set of measurements, staggered to the first, and so on, if necessary, to any degree of accuracy.

A surface isn't impossible to measure as flat, or curved, because instruments aren't long enough for a single measurement of it.

Slight slopes, slight curves, or perfectly flat, they can all be measured, and are measured, all the time, in many ways.

If a surface IS curved, no matter how large the surface is, it will never be flat, it will never MEASURE as flat.

A laser level that is accurate to 1/4 inch over 300 feet, doesn't mean it WILL be 1/4 inch out all the time, it will usually be LESS than 1/4 inch off, the 1/4 inch is it's MAXIMUM variance.

These variances can always be accounted for, with other measurements checking for it's accuracy, and variances.


No excuses, but nice try anyway.

No, it is accurate to 1/4 inch over 300 feet, and 1/4  inch accurate over the next 300 feet

Only if you perfectly align it.
If there is any uncertainty/error in the alignment, then that will impact the uncertainty as well.

I provided a diagram to show that, which you just ignored.
You really do love just ignoring everything that shows you are wrong.

and to confirm those measurements are valid, over each section, as constant throughout them all, we use a second line of measurements, halfway up the first sections, to account for any error in each transition point, if any are found.

That has the exact same alignment issues.
It doesn't matter how many extra points you use, you will still have these alignment issues which destroy your measurement.

Here is another simple diagram to demonstrate yet again that your claim is pure BS:

A laser level mounted at the first point will record the height of both the second and third point to be level within uncertainty.
A laser level mounted at the second point will record the height of the third point to be level within uncertainty.
Each time they are accurate to 0.01 units over a distance of 0.1 units, or 0.005 over a distance of 0.05; but over the 0.2 units of distance (actually 0.197 when measured perpendicular to straight down at the first point), you have an uncertainty of 0.038.
The uncertainty of the alignment increases the uncertainty of the measurement.

You have the uncertainty due to each of the 0.1 m long spans, as well as the uncertainty of the alignment which makes the overall uncertainty larger than simply adding up the 2 lots of 0.02.

It doesn't matter how much you want to ignore this fact, it wont magically change.

If you want the 0.02 as your uncertainty, you need to align them perfectly.
It is that alignment which you need to focus on, not throwing in more points.

A third set of measurements halfway up from the second one, can further confirm those points of transition, too.

And it will have the same issue of alignment making it still leave you with the uncertainty which cannot tell if Earth is flat or curved.

A surface isn't impossible to measure as flat, or curved, because instruments aren't long enough for a single measurement of it.

Slight slopes, slight curves, or perfectly flat, they can all be measured, and are measured, all the time, in many ways.

If a surface IS curved, no matter how large the surface is, it will never be flat, it will never MEASURE as flat.

As proven above, that is pure BS.
If you wish to claim it can be done, then prove it.
Either mathematically, or practically.
Show that by using a measuring device incapable of measuring the curvature over a single span that you can measure it by combing multiple spans, including explaining how you are aligning these measurements.

No excuses, but nice try anyway.

No, no excuses, just pathetic BS claims from you, which have already been refuted, with you ignoring the refutation.

Quote from: turbonium2 on October 15, 2022, 01:03:16 AM

No, it is accurate to 1/4 inch over 300 feet, and 1/4  inch accurate over the next 300 feet

Only if you perfectly align it.
If there is any uncertainty/error in the alignment, then that will impact the uncertainty as well.

It WOULD be perfectly aligned, same as everything ELSE would be.

Laser levels would be almost useless, if they couldn't be perfectly aligned, or 'plumb', or 'square', before anything is measured with them! That's rather obvious, isn't it?

You seem to think we cannot measure any surface accurately, when it is 'too long', whatever that's supposed to mean!

I'll try to explain why you're wrong, that they CAN measure for 'curvature', which you say is so incredibly 'slight' of a curve, over the Earth, that we cannot measure it, over a 'small' distance, which is any distance we CAN, and HAVE, measured!

The laser level is aligned, or squared, precisely, beforehand. It's height above sea level, or 0 feet altitude, is also set.

300 ft is 3600 inches, or 14400 quarter inches. The maximum error over that distance is 1/4 inch, when in perfect alignment, and would be, so it's accurate to 1/14400 unit over that distance, or 0.0000694 maximum variance. This gives you an idea of how accurate it is, without a doubt.

But here's the best part - even though it ISN'T perfectly accurate, being out by a tiny fraction like this, what we CAN do, and WOULD do, is measure within that 300 foot distance, to find out it is still perfectly aligned, or square, and measure the HEIGHT above sea level, at each point.

Or we can simply use shorter distances, with the laser level, which would make it more accurate, over each measurement, that also would work.

I'm trying to explain to you, that we absolutely CAN measure a surface as being flat, or curved, over a one mile distance, or more, with absolute accuracy, that is a fact. It may not be spoken of, may not be claimed as a fact, and they never do, in public, at least. But they certainly KNOW it is a fact, and some have actually MEASURED it, proving that it IS a fact.

With laser levels of today, almost anyone can do it. 

You're suggesting 'curvature' is too slight over 300 feet distance, because it has a 1/4 inch variance, which is less than 'curvature' is, over that same 300 foot distance.

So how did they know, when testing their laser level, that it actually WAS, at very most, inaccurate, over a distance of 300 feet, BY 1/4 inch?

Because that's the most important part you need to know about here.

They couldn't have known it was off by 1/4 inch at most, over 300 plus feet, unless they had MEASURED the CORRECT point, from 300 feet away!

Since you haven't disputed that figure, I assume you accept it as true, and we can move on...

Obviously, they couldn't know it was off by 1/4 inch, at most, unless they knew what WAS the correct point, from 300 feet away, or actually 324-5 feet away, or whatever it is, but they must have found out, it becomes less accurate at any LONGER distances, by measuring for the correct point there, as well.


And, if they have measured the correct point, where the laser level WOULD always hit, from 300 feet away, then obviously, we CAN measure it accurately, and HAVE measured it accurately, over a distance of 300 plus feet.

If THEY measured it, anyone else can measure it, too, the same way they did.

We know, they certainly knew, that a laser light is a perfectly straight line of light, so when they tested it for accuracy over 300 feet, or every 10 feet further out, or whatever, they had to set their targets at the exact same height, over all of the targets, at all distances outward from the laser level.

They had to set the targets at the exact same height, to a micron, or whatever is going to establish maximum accuracy.

When they measured a target at 300 or 400 feet away, they must have known the target point had to be at the EXACT SAME height as the laser light was, 300 feet way from it. They had to know it's exact direction, to set their target in the exact direction of the laser light, 300 feet away, at each side of it, too.

They set up targets at specific distances away from the laser level, with points on each target, set at the exact same height, exact same line of direction, as the laser level.

Why couldn't they have set the targets for 'curvature'? Because if they wanted to, each target would be set lower, to curvature from the laser level, to the targets, which would lower more and more, with each target further away, to match up with it.

To measure a point on a target, at 300 away from a laser level, means we can measure points on targets over any distance, because they never account for this completely made up 'curvature' of the Earth's surface.




   

300 ft is 3600 inches, or 14400 quarter inches.

Earth curvature over 300 feet with a 1 foot observer height is approximately 0.024 inches.

Why don’t you get yourself a laser and go out and do your 300 foot measurement and report back your findings.

It WOULD be perfectly aligned, same as everything ELSE would be.

HOW?
You can't just assert it would magically be aligned.

Laser levels would be almost useless, if they couldn't be perfectly aligned, or 'plumb', or 'square', before anything is measured with them! That's rather obvious, isn't it?

So you are using the circular reasoning I think I pointed out before.
You are assuming Earth is flat, to assume that when the levels level themselves they will all be levelling the same, to then claim they are all aligned.

But if Earth is round, they are levelling to the round Earth, just like I demonstrated in my image.
Laser levels don't need to magically align themselves with some magical reference plane. Instead they find which was is down and align to that. (But that still isn't perfect and is one source of error)
For your fantasy Earth that means they would all point the same way, but for the very real round Earth, that means each one will be pointing in a slightly different direction, just like I demonstrated in my image, where they are all pointing down towards the centre of Earth.
That means you don't have the alignment you need.

This means your argument is pure garbage as it relies upon falsely assuming Earth is flat to try and demonstrate Earth is flat.
But without that assumption it fails.

Each level in my diagram was perpendicular to the surface of Earth, that is level for a RE.

So you have been refuted once again.
The errors cannot simply be added because it relies upon assuming the alignment which you cannot honestly assume.

I'll try to explain why you're wrong

Considering you started with such a false claim of being able to perfectly align them to demonstrate Earth is flat which relies upon you assuming Earth is flat, I highly doubt you will succeed, as I highly doubt I'm wrong. But go ahead and try.

300 ft is 3600 inches, or 14400 quarter inches. The maximum error over that distance is 1/4 inch, when in perfect alignment, and would be, so it's accurate to 1/14400 unit over that distance, or 0.0000694 maximum variance. This gives you an idea of how accurate it is, without a doubt.

I have already demonstrated the math that shows that is not enough to detect the curvature.
The best one I could find is 1.5 mm per 30 m, using the maximum range of 400 m, you have an error of 20 mm, while the curvature is only 12.6.
This means the curvature is within the expected uncertainty. That means if you can't tell if it is flat or curved.

When you move it to another point, if Earth is curved, the alignment is out, so you can't just add the 2 uncertainties like you want to.

But here's the best part - even though it ISN'T perfectly accurate, being out by a tiny fraction like this, what we CAN do, and WOULD do, is measure within that 300 foot distance, to find out it is still perfectly aligned, or square, and measure the HEIGHT above sea level, at each point.

How?
By assuming Earth is flat and then measuring the height above the reference water level?
If so, as already pointed out, that relies upon you assuming Earth is flat, and thus cannot be used to demonstrate Earth is flat.
If Earth is round, you are measuring relative to a reference sphere (or geoid more generally), and that means you aren't ensuring the alignment is perfect and you aren't able to show Earth is or isn't round.

I'm trying to explain to you, that we absolutely CAN measure a surface as being flat, or curved, over a one mile distance, or more, with absolute accuracy, that is a fact.

No, you aren't explaining anything.
You are just making more and more bold assertions with nothing to justify them.

The closest you have come to an explanation is by appealing to the laser's self-levelling. But while that doesn't give you the alignment it needs. So you failed with that. And that was before you claimed to try to explain it.

Your attempt at an "explanation" was nothing more than you just asserting yet again that you can measure it.

Try an actual explanation. One which doesn't rely upon you already assuming Earth is flat. And one which clearly explains how each step is done instead of just magically asserting that it happens.

But they certainly KNOW it is a fact, and some have actually MEASURED it, proving that it IS a fact.

Plenty of people have measured the curvature of Earth and know it is round. That is a fact.
No one has been able to measure Earth to the required level of uncertainty to demonstrate it isn't curved as science shows us it is.

So how did they know, when testing their laser level, that it actually WAS, at very most, inaccurate, over a distance of 300 feet, BY 1/4 inch?

By understanding how the laser works.
They don't need to actually measure at that distance to give an estimate of the uncertainty.
The more accurately quoted uncertainty would be in arcseconds or another angular unit of measure.
The stated accuracy comes from the beam divergence and the accuracy of its self-levelling.

They couldn't have known it was off by 1/4 inch at most, over 300 plus feet, unless they had MEASURED the CORRECT point, from 300 feet away!

Did you bother reading the document I provided, which actually describes the specifications of the laser level?
https://d3r4tb575cotg3.cloudfront.net/static/topcon_518668_rl-h5a_brochure_a_team_en_us_low_reseller.pdf
Notice how it doesn't say 1.5 mm at 30 m or anything like that?
Instead it says this:
"±10 Arc second horizontal accuracy"

That is the actual uncertainty of the instrument.
The 1/4 of an archaic unit over 300 plus archaic units is based upon an angular uncertainty.
The figure quoted on their website was 1.5 mm at 30 m.
At that stage the curvature is just 0.07 mm. Tiny compared to the uncertainty of the laser.

You still don't seem to understand that you don't need to directly measure something to determine what the value is.

But no, they don't need to measure it.
To show the insanity of that, consider all the other possible distances.
Sure, you are going to roughly 100 m.
But what about 50 m? Do they need to measure there as well?
What about 1 m? 2m? 3? 4? 5? 6? and so on?
Do they need to make measurements over 100 separate distances, performing multiple measurements at each to determine the accuracy?
If so, what about at 50.5 m? or 50.1? or 50.01? and so on.
They could be doing this forever, and according to you it still wouldn't be enough.

The entire rest of your argument seems to be based upon this fantasy of yours.

Back in reality, they measure the angular variance, which any rational, intelligent person (who understands basic trig) can use to calculate the uncertainty at any given range.

Since you haven't disputed that figure

No, instead I pointed out your figures were useless because they are for a laser range finder, not a laser level, and you made no attempt to correct them.

If THEY measured it, anyone else can measure it, too, the same way they did.

People can and have measured the curvature of Earth with a theodolite over long distances. A simple example of this is measuring the angle of dip to the horizon.

Again, you not liking reality wont change it.
And your fantasy of how they set it up in no way helps you with your claim of magical perfect alignment, nor your claim that laser levels are accurate enough.

It WOULD be perfectly aligned,

 Based on measuring and aligning with what instrument with what factor of error?

Good thing people smarter than you have devised an actual experiment that eliminates error, account for “illusion” and refraction.

Proof of Earth Curvature: The Rainy Lake Experiment

Rainy Lake Experiment: Conclusion

http://walter.bislins.ch/bloge/index.asp?page=Rainy+Lake+Experiment%3A+Conclusion


Summary
All data and observations agree with the predictions of the Globe Model, which includes Terrestrial Refraction. The predictions for the Flat Earth Model, however, contradict the observations.

The Rainy Lake Experiment shows even better than the Bedford Level Experiment that the earth is a globe, since we also have GPS measurements that are not influenced by Refraction or Perspective, but are of a pure geometric nature. GPS measurements directly provide the radius of the earth.

Only one conclusion remains:

The earth cannot be flat, but is a globe with a mean radius of 6371 km!

With flat earther’s debunking themselves…

Flat-earthers tried to prove the Earth was flat with a videotaped experiment and it did not go well

https://www.businessinsider.com/flat-earthers-tried-to-prove-the-earth-was-flat-and-it-did-not-go-well-2019-2

When the experiment began, the light didn’t appear on camera. A perplexed Jeran radioed Henrique to confirm the height of the light at 5.18 meters (17 feet) above sea level. On a flat Earth, he should be seeing the light. He then asked Henrique to lift the light above his head. Lo and behold, the light shined through.

“That’s interesting,” Jeran commented in the clip.

And you know what? It is interesting. This experimental set up has been a staple of flat-Earthers since 1836, when Samuel Birley Rowbotham first did it on the Old Bedford River. Time and time again, it has revealed the curvature of the Earth. Still, it is important to continue to repeat classic experiments as repetition is one of the cornerstones of science.

If you missed it…

“when Samuel Birley Rowbotham first did it on the Old Bedford River. Time and time again, it has revealed the curvature of the Earth”

But if Earth is round, they are levelling to the round Earth, just like I demonstrated in my image.
Laser levels don't need to magically align themselves with some magical reference plane. Instead they find which was is down and align to that. (But that still isn't perfect and is one source of error)

These are actual, solid, physical surfaces that are being measured with real, actual instruments, the only 'magic' is claiming it is measuring your made up 'curvature', without even MEASURING it, until they say they've measured it from 'space', or in 'orbit', where everything is 'proven', like a made up magical force called 'gravity', was also 'proven'.

'Space' is a magical place, which doesn't exist as they have claimed, not even close to it, in fact. The actual facts, real evidence, prove Earth IS flat, and more proof in future, it is inevitable.

Planes will measure for level flight, when they reach a specific altitude, while any adjustments during flight, are corrected for afterwards, and they return to level flight at altitude.

If planes measured for a level flight, but was for a curved flight path, that would require planes to make a physically curved path, to remain at altitude, while flying 'level' to a curved surface below it.

A level flight cannot be a curved flight, measured AS level to a curve. Because a curved path must be flown as a curve, as an arced path, as a PHYSICAL curve has to be flown by planes, to follow the same altitude of a curved surface below it, throughout the flight.

So planes can't measure for your 'curvature', when they only can measure around the plane itself, at very most, they cannot measure beyond that, they have to continually measure it, over and over again, during the whole flight.

If there WAS 'curvature', planes would measure it continually, over and over again, in SMALL, SEPARATE SEGMENTS, over the same, small distance, so even if there WERE 'curvature' on the surface of Earth, planes wouldn't be able to measure for it. Not with these instruments, anyway.

How could your magical made up force, 'gravity', make instruments measure level to a curved surface of a ball Earth in 'space'? Planes can only measure for level flight over that small distance, over and over again, of the same 0.0025 of 'curvature', each time, over and over again, throughout the flight.

In order to ACTUALLY account for your 'curvature', when it only measures a small distance over and over again, that is where instruments would HAVE to measure for a 0.0025 inch of curve, and would have to ADJUST for it, no matter HOW small it is, no matter how long it takes before we've developed an instrument to measure it, because that's how it would be, if Earth were a ball in 'space'.

   

These are actual, solid, physical surfaces that are being measured with real, actual instruments, the only 'magic' is claiming it is measuring your made up 'curvature', without even MEASURING it,

Surveyors measure curvature all the time. Engineers use that data to design & construct structures that require earth curve measurements. You’ve been provided all of that evidence and information many times.

So, in short, you are incorrect.

Quote from: turbonium2 on October 22, 2022, 12:58:32 AM

These are actual, solid, physical surfaces that are being measured with real, actual instruments, the only 'magic' is claiming it is measuring your made up 'curvature', without even MEASURING it,

Surveyors measure curvature all the time. Engineers use that data to design & construct structures that require earth curve measurements. You’ve been provided all of that evidence and information many times.

So, in short, you are incorrect.

No, surveyors that work on real projects say that they always 'assume' surfaces are FLAT, but it's far more than an assumption, because they actually WORK from this 'assumption', and then others will BUILD STRUCTURES on that same 'assumption', and they WORK PERFECTLY from that 'assumption', and they always DO work from this very same 'assumption', all the time!

They can call it anything they want to, but their actions show what it really is, and it is certainly NOT just an 'assumption', it is known to be flat, measured as flat, and built as flat, because it IS flat.

Surveying is about accurate measurements of the surface, and does NOT 'assume' anything, especially if they KNOW it is not true, and if they knew the surface was NOT flat, and also knew it was CURVED, they'd say it IS a curved surface, assume they're curved, work with a curved surface, make it flat for building on it, which would make perfect sense, and would be completely logical.

 

These are actual, solid, physical surfaces that are being measured with real, actual instruments

And none of that helps your claim.
Again, in reality, laser levels level themselves.
They don't magically align to some magical flat surface. They level themselves.

That makes your argument circular. You rely upon your false assumption that Earth is flat to falsely claim the levels are magically aligning themselves, to falsely claim they could measure the curvature, to falsely claim Earth is flat.

The actual facts, real evidence, prove Earth IS flat

Then why are you entirely incapable of providing a single bit of it?
Why do you instead resort to attacking the RE with pure BS?
Why do you resort to repeating the same refuted nonsense again and again?

You have no evidence that Earth is flat at all.

Planes will measure for level flight

Yes, LEVEL! Not flat.
We have been over planes quite a lot, with you fleeing from it because you couldn't defend your BS.
Why come back to it just to get refuted all over again?
Why flee from your laser levels?
Does that mean you now fully accept your laser levels cannot measure the curvature of Earth because of issues with alignment?

If planes measured for a level flight, but was for a curved flight path, that would require planes to make a physically curved path, to remain at altitude, while flying 'level' to a curved surface below it.

And the amount they would need to curve would be hidden in the noise.
They would not be able to tell, not without incredibly precise equipment.

A level flight cannot be a curved flight

You not liking reality will not change it.

So planes can't measure for your 'curvature'

You are the one claiming they magically measure Earth to be flat, even though you can't explain it at all.

If there WAS 'curvature', planes would measure it continually, over and over again ... planes wouldn't be able to measure for it. Not with these instruments

This shows just how pathetic your argument is.
You can't even remain consistent for a single paragraph.
On one hand you claim they should constantly measure it and need to adjust, only to turn around and say they wouldn't be able to.

How could your magical made up force

I'm not the one believing in magic.
That would be you.

instruments measure level to a curved surface of a ball Earth in 'space'?

We have been over this, there are 2 main ways. One is using GPS.
But the simplest is air pressure.

In order to ACTUALLY account for your 'curvature', when it only measures a small distance over and over again, that is where instruments would HAVE to measure for a 0.0025 inch of curve, and would have to ADJUST for it, no matter HOW small it is

Again, pure BS.
Again, when planes are flying, they maintain their altitude.
The pilot or autopilot will constantly be adjusting the plane to do so.
As they do that, there is no need for them to specifically account for the curvature.

Stop bringing up the same refuted BS as if it hasn't already been refuted.

No, surveyors that work on real projects say that they always 'assume' surfaces are FLAT

Prove it.

it is known to be flat, measured as flat, and built as flat, because it IS flat.

As all the evidence available shows Earth is curved or can't tell if Earth is curved of flat, it cannot be known to be flat, as it isn't flat.

Surveying is about accurate measurements of the surface

And can and does measure the curvature.

if they knew the surface was NOT flat, and also knew it was CURVED, they'd say it IS a curved surface

And how many surveyors do you know that say Earth isn't curved, that Earth is flat?

they'd say it IS a curved surface, assume they're curved, work with a curved surface, make it flat for building on it, which would make perfect sense, and would be completely logical.

Again, stop repeating the same refuted BS.
For the vast majority of projects, the curvature of Earth is less than the roughness of concrete.
They are not going to need to care about that.
It makes no sense to try to account for something that would be lost in the noise.