Laser curvature test on lake Balaton

[studiot]

 

I can notice from your video in Youtube that your measuring white board is around 1.35m high.

 

How did you take your measures starting in row 15 in your table as those are all higher than 1.35m? After 12min in your video the laser is not hitting the white board anymore ...

 

I also noticed the beam diameter in the white board getting bigger and bigger. At around 14min the circle is nice and small. At around 19:10, the circle is barely recognizable. How did this "spread" impact your measures? How did you estimate the correct beam height as it was not nice and small anymore?

 

Great structure you put there by the way.

 

Good point, +1

 

Variation of spot size is an important point when finding the centre of a laser beam.

 

 

Sandor Szekeley post#9

 

We use a slope correction method at the leveling distance of 720 meters to make a true horizontal level to a 0.001 degree accuracy at the position of the laser on the shore

 

Are you aware that a collimation error of 0.001 degrees corresponds to 1.3 metres at 77km range?

 

By the way, .001 degrees is nearly 4 seconds of arc and pretty poor accuracy for this sort of work.

Standard geodetic work at this range would be at least two orders of magnitude finer and really accurate work better still.

Edited September 12, 2016 by studiot

[michel123456]

 

I can notice from your video in Youtube that your measuring white board is around 1.35m high.

 

How did you take your measures starting in row 15 in your table as those are all higher than 1.35m? After 12min in your video the laser is not hitting the white board anymore ...

 

I also noticed the beam diameter in the white board getting bigger and bigger. At around 14min the circle is nice and small. At around 19:10, the circle is barely recognizable. How did this "spread" impact your measures? How did you estimate the correct beam height as it was not nice and small anymore?

 

Great structure you put there by the way.

He is using a disco laser for showtime. (pointed out in the other forum I was talking about).

Edited September 12, 2016 by michel123456

[Sensei]

The laser was leveled using the boat so at 720 meters on the GE model, the beam should have risen from the surface from 1.25 starting height to 1.29. The ended up setting it to 1.32 because moving it in .01 adjustments proved difficult without an appropriate adjustable mount. What they were looking for was either a curve in the data plot against distance or an updward curve in the height data. What the test showed was a straight ascending line. The video shows the leveling at 9 minutes. https://youtu.be/GBhDFO4NMrw?t=9m

Questions to OP of this thread.

 

I just clicked link (have not watched it, 30 mins!), and wow, there is "Flat Earth | Laser Test Proves The Flat Earth" title..

 

Is it serious?

Literally.. ?

 

If you're taking it literally, as flat Earth like in middle ages, then why don't you build rocket like these guys:

It reached 30 km.. 3 times as high as commercial airplanes.

And 7%-9% of altitude of ISS space station (330-410 km)

 

How about making your own Hydrogen filled balloon, with GPS and couple cameras recording flight.. ?

 

If Earth is flat, how curved shadow on the Moon appears?

Earth is blocking photons traveling from the Sun..

[imatfaal]

!

Moderator Note

 

Guys n Gals.

Whilst the motivation for the experiment (from elsewhere and titles) and the obvious other tests to show that its conclusion is flawed are interesting - they are not really part of this thread. Can we keep to why the experiment showed the result it did - personally I am finding it very interesting especially Studiot's contributions; let us not derail that with an argument we already know the answer to.

 

[studiot]

It would appear that the OP is indeed another attempt to push the misguided flat earth dogma.

 

However instead of ridicule or minor arguments against his results we should all consider this.

 

Sandor's results, if the survey was properly conducted, will be correct.

 

The water surface departs from following the Earth's curvature; it is essentially flat.

 

Note my question in post#6 that has gone unanswered

 

 

Studiot

If the lake is less than 5m average depth then it is a very thin layer of water in comparison to the curvature of the Earth which is up to two orders of magnitude greater.

 

In other words the lake is a surface film.

 

Furthermore the bottom must also follow this profile.

 

Since the underlying land is nearly planar, why would you expect a surface layer of water to be anything else?

 

 

Lake Balaton is an important lake because of its size and topography.

Only 12 metres deep at max and much less on average as my early question shows there is a basic issue with surveying the water/air surface.

 

[aside]Although I have not been there since 1956 and at that time I was too young to be interested in geomorphological history, my daughter had a wonderful holiday there earlier this year.

I can definitely recommend it, it is one of Europe's Geopark sites.[/aside]

 

As such it has attracted much august study about its formation which reveals the clue to the conundrum.

 

Lake Balaton is a rift lake.

 

That is it lies in the bottom of a rift valley.

 

Rift valleys, such as the African and Red Sea rifts, are noted for their flat bottoms, which can run for great distances.

Rifts are no great respectors of the Earth's curvature.

 

So the underlying topography is, well, flat.

 

And a very shallow lake has formed with sediment deposits on the rift valley floor giving a slight slope to the bottom.

 

But since the average depth is only about 3 m

 

How can the water surface not be as flat as the ground on which it is resting?

 

This is not support for the flat earth view, just modern science sorting the fact from the fiction and properly acknowledging real facts.

 

Here is a sketch geo history of the rift.

 

Edited September 12, 2016 by studiot

[imatfaal]

Studiot - can I re-iterate to ensure I have this straight in my head

1. the lake is a rift lake

2. the particular formation of this lake means that its lake bed is ruler flat (ie does not follow curvature)

3. it is also exceedingly shallow for such a lake

4. the water therefore conforms to the lake bed and is also ruler flat

[studiot]

Studiot - can I re-iterate to ensure I have this straight in my head

1. the lake is a rift lake

2. the particular formation of this lake means that its lake bed is ruler flat (ie does not follow curvature)

3. it is also exceedingly shallow for such a lake

4. the water therefore conforms to the lake bed and is also ruler flat

 

In essence, yes.

 

But for 3 there are many such rift lakes, including one nearby that is 1m deep (Neuseidler See). Of course the Red Sea is much deeper.

 

Note I used the word flat, not level, although rifts are no respectors of level lines either.

[imatfaal]

 

In essence, yes.

 

But for 3 there are many such rift lakes, including one nearby that is 1m deep (Neuseidler See). Of course the Red Sea is much deeper.

 

Note I used the word flat, not level, although rifts are no respectors of level lines either.

 

re 3 - I wikied rift lakes and it said they could be exceedingly deep so I made a bad assumption that most were

 

flat vs level - OK so they are a flat inclined surface rather than a level surface which would be both flat and perpendicular to radius?

[studiot]

 

re 3 - I wikied rift lakes and it said they could be exceedingly deep so I made a bad assumption that most were

 

flat vs level - OK so they are a flat inclined surface rather than a level surface which would be both flat and perpendicular to radius?

 

Fracture lines AKA displacement lines in both materials science and physical geology tend to be straight rather than curved.

Indeed they often cut across curved structures such as folds as can be seen at many classical unconfomities in geological sites and textbooks.

 

This characteristic can be deduced from energy considerations.

 

Who said Nature avoids straight lines?

[Boxer]

Studiot - can I re-iterate to ensure I have this straight in my head

1. the lake is a rift lake

2. the particular formation of this lake means that its lake bed is ruler flat (ie does not follow curvature)

3. it is also exceedingly shallow for such a lake

4. the water therefore conforms to the lake bed and is also ruler flat

On that scale matter have no choice but to follow the equipotential gravitational field and conform to the geoid, every elevation is measured from that level surface. The lake is level to the ellipsoidal levelsurface.

Also I am here to inform that Sandor Székely don't have any affiliation or contribution to the LIDAR Balaton observation or with any Other hungarian or other scientific institutions, despite his misleading original post. Just to clarify.

Edited September 12, 2016 by Boxer

[studiot]

On that scale matter have no choice but to follow the equipotential gravitational field and conform to the geoid, every elevation is measured from that level surface. The lake is level to the ellipsoidal levelsurface.

Also I am here to inform that Sandor Székely don't have any affiliation or contribution to the LIDAR Balaton observation or with any Other hungarian or other scientific institutions, despite his misleading original post. Just to clarify.

 

Are you suggesting that geological processes such as mountain upthrust, volcanoes, rifting, follow geopotential lines?

 

Perhaps you could explain?

 

Do you also think they follow Ley lines?

[MrMaker]

It would appear that the OP is indeed another attempt to push the misguided flat earth dogma.

 

However instead of ridicule or minor arguments against his results we should all consider this.

 

Sandor's results, if the survey was properly conducted, will be correct.

 

...

 

 

That's the main point. I want to understand how he measured beam height greater than 1.35m. His method is not specified. I also want to understand how he estimated the height of the beam as the spot size is getting bigger and bigger over distance.

 

We are spending a lot of time discussing about possible reasons for the set of results, but I think the set of results are estimated, and not measured, at least taking into account what was shown in the video.

[Boxer]

 

Are you suggesting that geological processes such as mountain upthrust, volcanoes, rifting, follow geopotential lines?

 

Perhaps you could explain?

 

Do you also think they follow Ley lines?

 

I made the above statement because the OP tried to plant confusion between elevation and the curvature of the earth.

Off course we have deviation from the reference ellipsoid (in more precise measurements geoid) that called geographical elevation, but consider the earth radius 6371 kilometers and the maximum elevation 8.8 kilometers to put that in scale.

 

Edited September 12, 2016 by Boxer

[michel123456]

From the given data, it looks the Balaton lake is not level. It flows like a river. It has a level +150.55 at inflow (left on the picture) and 149.65 at outflow, a difference of 90cm from level.

(I have added labeling on the maps provided in the OP)

 

The experiment was taken at a point after a bottleneck, transverse to the lake. From the color legend, the lake shows a slight level difference transverse also.

If the experiment has been correctly conducted, then the surface lake is concave along the experiment. Eventually the concave of the lake surface and Earth curvature would cancel each other and gives an almost perfectly flat section.

But that would be a extraordinary coincidence that a F.E. knew about this and decided to take an experiment right at this spot and at the right time of the year.

Edited September 12, 2016 by michel123456

[studiot]

 

That's the main point. I want to understand how he measured beam height greater than 1.35m. His method is not specified. I also want to understand how he estimated the height of the beam as the spot size is getting bigger and bigger over distance.

 

We are spending a lot of time discussing about possible reasons for the set of results, but I think the set of results are estimated, and not measured, at least taking into account what was shown in the video.

 

Yes we all would like some hard information instead of a half hour video and a proper method statement, along the lines of the two in my post#40.

 

As to how the butler did it, Japp, I don't know but here is another story from memory lane.

 

My firm was commissioned to design and oversee the construction of a border outpost town in Saudi Arabia.

I was twice sent there to sort out problems that had arisen, the first time was to help the contractor figure out why his setting out was going haywire.

This was the first time in my life I found the need to apply temperature corrections to a steel tape - but that is another story.

 

The second visit they had many buildings constructed, but it was discovered all the floor slaps had been cast with no level control.

That is they were all set to random levels.

 

In order to establish these slab levels so we could redesign the roads, I took a doorstep level on each building and caused consternation back home when the level book was returned.

 

As this was in the Saudi/Quatar desert the buildings were flat roofed.

I set up a level on top of a central roof and fixed leg, several metres long to a standard (3m I expect) levelling staff.

This I sent round with a couple of assistants to stand on each doorstep in turn.

It was necessary to perform the staff waving exercise I noted with the boat's mast earlier in this thread.

 

When they saw my results, head office couldn't understand how I had 8m staff readings recorded in my book.

 

 

 

I made the above statement because the OP tried to plant confusion between elevation and the curvature of the earth.

Off course we have deviation from the reference ellipsoid (in more precise measurements geoid) that called geographical elevation, but consider the earth radius 6371 kilometers and the maximum elevation 8.8 kilometers to put that in scale.

 

 

If you are making a valiant effort to warn us of something but struggling with English, thank you very much.

 

But I find your statements more bizarre than those of the OP.

 

I have already asked you to elaborate.

[Boxer]

From the given data, it looks the Balaton lake is not level. It flows like a river. It has a level +150.55 at inflow (left on the picture) and 149.65 at outflow, a difference of 90cm from level.

post-120902-0-23645600-1473549296.jpg

(I have added labeling on the maps provided in the OP)

 

The experiment was taken at a point after a bottleneck, transverse to the lake. From the color legend, the lake shows a slight level difference transverse also.

If the experiment has been correctly conducted, then the surface lake is concave along the experiment. Eventually the concave of the lake surface and Earth curvature would cancel each other and gives an almost perfectly flat section.

But that would be a extraordinary coincidence that a F.E. knew about this and decided to take an experiment right at this spot and at the right time of the year.

 

Well considering that histogram shows ellipsoidal heights ( "The Ellipsoidal Height of a point of the Earth Surface is the distance He from the point to the ellipsoid.") the surface of the lake pretty much follows the shape of the geoid, and certainly not flat or concave. But leveled to the geoid, with a slight deviation pointed out in the paper.

[michel123456]

Well considering that histogram shows ellipsoidal heights ( "The Ellipsoidal Height of a point of the Earth Surface is the distance He from the point to the ellipsoid.") the surface of the lake pretty much follows the shape of the geoid, and certainly not flat or concave. But leveled to the geoid, with a slight deviation pointed out in the paper.

You are correct. But that was not all I wanted to say.

 

Here below a quick sketch

 

 

After the bottleneck, around the outflow, the water surface is (suggested to be) like a funnel.

Or a very soft vortex (maybe).

If you take a transverse section of a funnel, you get a conic curve, as in the sketch of section AA'. That is what I meant by the word "concave" in my previous post.

[Boxer]

 

If you are making a valiant effort to warn us of something but struggling with English, thank you very much.

 

But I find your statements more bizarre than those of the OP.

 

I have already asked you to elaborate.

 

Sorry, now I see how it could be misunderstood. To determine elevation and make accurate maps, we need a model of earth shape and a coordinate system, a fixed reference level surface. The elevation above the ellipsoid (ellipsoidal height) is the elevation above a mathematical model that approximates the shape of the earth. It was very accurately described in wikipedia :

"TheThe World Geodetic System (WGS) is a standard for use in cartography, geodesy, and navigation including by GPS. It comprises a standard coordinate system for the Earth, a standard spheroidal reference surface (the datum or reference ellipsoid) for raw altitude data, and a gravitational equipotential surface (the geoid) that defines the nominal sea level.."

 

Also in a diagram, The relationship between topography and the ellipsoid level surface :

(http://www.ee.co.za/article/accuracy-kinematic-gnss-height-observations-road-surveys.html)

 

 

[studiot]

Michel, Boxer thank you both.

 

So which height is shown in the histogram and why is it shown as a histogram?

 

It is listed at around the 150m figure.

 

Here is an extract from Wiki

 

 

Area: 592 km²

Length: 77 km

Surface elevation: 105 m

Mean depth: 3.2 m

Catchment area: 5,181 km²

Cities: Siófok, Balatonfüred, Keszthely, Tihany, Balatonszemes,Balatonvilágos

 

Which is 45 m different.

 

So which height is which?

[Mordred]

Some interesting details coming out...

 

I still don't agree on The Op's assumption of refraction being slightly upward. I see that as a cover up to make their data more accurate.

 

However I doubt the OP will show the required calculations. It may or may not be a factor as Studiot mentioned. However we have no means available to confirm this.

 

For example moist air has a lower refractive index than dry air. The OP mentioned 71% humidity. So how much inversion would be required to overcome the natural tendency for the laser to follow the geodesic curvature??

 

It will be interesting to see the response of the OP to the lake level data you guys are supplying...

 

I've given up on hoping the OP supplying the refractive index during the experiment

[michel123456]

Michel, Boxer thank you both.

 

So which height is shown in the histogram and why is it shown as a histogram?

 

It is listed at around the 150m figure.

 

Here is an extract from Wiki

 

 

Which is 45 m different.

 

So which height is which?

I don't know.

 

What I know is that each country has its own reference system which may not coincide with the ellipsoid. In Greece where I am the national system is the ΕΓΣΑ 87.

[Boxer]

So which height is which?

In figure (a) they measured the ellipsoidal heights and figure (b) showing the orthometric height (ellipsoidal height corrected with the geoid undulation). see below.

 

The following will also answer Michel's concerns about the fluid dynamics and geometry of the lake surface.

 

The Aim of the study cited in the original post (can be read here :http://publik.tuwien.ac.at/files/PubDat_228814.pdf ) was to show that measured variation in ellipsoid heights (measured from a surface of the ellipsoid model with rotational symmetry) in standing water surface are matching closely the geoid undulations ( surface defined by points of equal gravitational potential, differing from the rotational symmetry) of that area.

 

The study showed the water surface is close to hydrological equilibrium following a the local curve of the geoid ( "following a gravity potential isosurface at a constant orthometric height above the geoid" )

 

 

(runned out of post count, so will continue tomorrow )

 

Edited September 12, 2016 by Boxer

[Mordred]

To explain my concern, on refractive index lets consider an example. The refractive index is typically highest the closer to the surface. Lets assign value N_1. At higher elevations temperature and pressure drop. Giving refractive index N_2.

 

Snells law [latex]\frac {sin\theta_1}{sin\theta_2}= \frac {N_2}{N_1}[/latex]

 

So as you increase elevation the ray will curve downward. This occurs regardless of the curvature of the Earth.

 

The humidity along the water surface will be higher than the ambient air. This gets into the potential of ducting...

 

The question is can we determine that the OP has the right conditions for sub-refraction? Which is possible but I don't see sub-refraction with the environment conditions mentioned in the OP..

We do talk about refraction in the video as if there is any possible refraction of the laser beam it is bending upwards as we have reversed atmospheric conditions at dawn than in the afternoon when the mirrage effect is possible to detect.

 

 

Too bad the OP can't provide the proof that sub-refraction and not ducting is occurring. The quoted section occurs more readily over deserts with temperature inversion. Its a different situation with humidity of 71%.

 

[latex]N=77.6\frac{P}{T}+3.73*10^5\frac {e}{T^2}[/latex]

 

first term is dry air second term moist air. Key note the temperatures may invert but the pressure does not. In point of detail the moist air off the lake increases the pressure near the surface 😲

 

That quoted section is just too convenient as "JUST THE RIGHT conditions to get the results I want...

 

I've been tinkering with the numbers all night. I can't find a combination that has a refractive curve upward from the Earths surface. Not within reasonable temperature variations. There is an extent in range of the signal due to reduced curvature but in all cases there is still a slight downward curve.

 

Anyone willing to show the calcs of upward refraction?

Edited September 12, 2016 by Mordred

[studiot]

Thank you again, Boxer for the partial explanation.

 

But still why present the data as a histogram?

 

If we regard this as a statistical sampling of the surface water then it seems to point to the Wiki number of 105 being the mean of the histogram.

 

But this information is useless without knowing what part of the water surface was sampled.

All the flight paths were along the edge.

 

Like the rest of the information provided it requires a proper method statement and declaration of variables to accompany it to make any true sense of it.

 

Further none of this alters the possibility of local flatness of the geoid and ground surface (ie the lake bed) supporting a flat water surface since the geoid 'corrections' are not shown.

[Mordred]

I have to admit I also like your approach Studiot. +1

Anyone willing to show the calcs of upward refraction?

Just in case anyone wishes to take up this challenge ROFLMAO... units for temp are in Kelvin. Pressure in mbar. N= n*10^6

 

It is possible as this has occured in previous experiments. The challenge is to show for this experiment.

 

Also good work Michel and Boxer.+1 each

Edited September 12, 2016 by Mordred