Laser curvature test on lake Balaton

[DarkStar66]

(1) Please model the beam size on the boat clip

 

(2) on the 118.5 cms / 132 cms debate I attached a video that was deleted from meta. Zack clearly explains the math with autocad: the beam should be at 3.19 meters (instead of the 4.32 meters)

(3) That makes marginal difference in the outcome as the beam was recorded at 1.8 m - still a huge 1.4 m difference

 

(4) My question: if the beam was spread out to more meters as you suggest, how come that the beam is not seen on the retroreflective surface few inches below, but only in the camera lenses?

 

beam divergence comp 1.png

 

(5) I have explained that NONE of the measurements were taken with the tape. At C1, C2 and C3 leveling process Dave used a tape to tell my laserist a number to calculate the increment of raising the laser. It has nothing to do with the measurements! Dave could as well say only "raise up".

 

(6) We have explained in 2 video already that the photoshop measurements are inaccurate. I can not upload them here. Admin - any suggestions?

 

(7) 1st video: explaining the GE and FE calculated expected beam height. The 3.19 meters beam center is still not possible on the GE model.

 

(8) Your calculation on the board height from angle is inaccurate.

 

"There is very good reason here to believe that this mark was placed incorrectly. That throws everything else about your calculations off."

 

(9) So you believe in something that throws my calcualtion off...

 

" Assertions do not make the data reliable."

 

(10) Please provide me your unrefutable datat that shows that my divergence was not as I said with the 0.08 mRad collimator. Unless you make a model of beam divergence that is coherent with the photo evidences, your claim is only an opinion. Check the above pictures and my concerns on your guess of beam divergence.

 

I see no evidences supporting your argument, you have not even modeled it if it possible.

 

 

(11) You wrote: "But refraction doesn't require some kind of dynamic 'change' to make it happen. Everything could be entirely stable."

this is wrong, refraction is caused by CHANGE in the medium light travels through:

In a constant density, pressure , temperature medium there is no refraction - only retardation.

 

(12) How come, that we make a good understandable definition of what we experience: the NUDTZ non uniform density transition zone - and it is criticized.

 

(13) Standard refraction used in geodezical terrain measurements is 0.4 millimeter / kilometer

 

(14) your comments on the avarage amount of refraction and the refraction calculator are wrong.

 

This shows the beam spread progression from C4 to C11

 

 

(1) that was already shown in the video very clearly

 

(2) I'll wait for the evidence - you can send me a link if necessary

 

(3) Once you correct the slope (1.25-1.185)/720m which is a slightly downward slope and account for the beam spread, and Earth curvature, my estimated height for the lower edge of the beam is 2.1 meters at 6044m out, so just above your board a bit.

 

(4) your image is not sharp enough to answer that -- which direction is the pilot facing at that exact moment? (he keeps turning around to check where the laser is)

 

(5) In image C5 you are clearly using that point as 130cm and put the center of beam at 134cm -- so it doesn't matter if you USED IT for the measurement, you are calling that point 130cm above the water.

 

And then in C11 we get the same reflection off the metal bar, at the same point, and you marked that as 1.84 -- how did the metal bar get higher?

 

(6) It doesn't matter if you think the pixel estimates are wrong or not - it's irrelevant to the actual problem - you haven't shown that your measured heights are reliable. That's all I'm asking for and I've merely shown WHY it is a valid concern.

 

(7) Yes, if you leave in all your methodological errors it doesn't work -- that's the point

 

(8) We've shown how they were done -- you would need to show they are inaccurate by showing how the height was measured accurately.

 

(9) I don't 'believe it' I showed the problems from numerous lines of evidence.

 

(10) See attached image above

 

(11) You misquoted me - I saio "If by change you mean the medium contains components with different refractive indices then yes. " -- all you did was restate what I already said.

 

(12) Please define your term mathematically - then we can discuss further.

 

(13) you cannot estimate refraction as a simple linear function, that's why ATY uses % of curvature as an approximation for the overall integral.

 

(14) you didn't establish they are wrong, you just asserted it - I cited my source, feel free to argue with ATY I have zero interest in discussing irrelevant portions of the calculator any further as I already stated very clearly this has nothing to do with your experiment.

[Mordred]

Yes the evaperation ducting can cause a huge number of optical problems. Even having multiple potential laser paths.

 

This can easily cause motion in every direction with a preferred direction due to wind movement. (think of the effect moving water can have). In the evaperation duct the humidity approaches 100% as you approach the water surface.

 

During the test. If possible

 

at each point record the temperature, at laser elevation and surface water temp. humidity, and wind speed and direction. Ideally the atmosphere chemical composition would also be useful. Oxygen, nitrogen, carbon dioxide %, etc is useful data for location refraction values.

 

The atmospheric pressure is also needed to fine tune calcs. This data can be used to further analyze your dataset.

 

Also include the technical datasheet for the equipment your using. (ie the laser.. ). The emitted wavelength etc is important...

 

In terms of beam dispersion, the evaperation duct can easily increase the beam radius. (extremely easy)

 

I would recommend on your backboard you have reference grid lines both horizontal and vertical. This way we remove the need to pixel count etc the beam radius from photos etc.

 

Remember the more data you provide, the greater your accuracy becomes. It also reflects diligents to important potential influences and steps to mitigate or acccount for their influence. For example if you sample the above list at each point. You can fine tune refraction data at each measurement point. ( physicists studying your paper, just love these details).

 

Of course they will also want to see your calculations. (To that end, I'm still putting together the list of formulas with correction formulas for locality).

 

Its quite intense...

 

Remember a good paper, will contain sufficient data, that doesn't require studying a photograph etc.

 

1) Appropriate formulas

2) accurate data, the more measurement data the better

3) A detailed list of possible measurement errors and the corrections. (including the related calculations that the corrections are effective)

4) good reference papers, including previous studies.

 

There is a rule of thumb, physicists usually only accept mathematical proof, that corrections are in place... They won't accept a verbal only description. Nor will they take anyones word that corrective measures are in place. Unless they can mathematically confirm the corrective measures...

 

For example an image isn't sufficient. What distortions are inherent to the image?

 

Just a side note, personally if I'm studying a paper proposing a new model and datasets. I personally won't accept any paper that doesn't include a detailed list or error margins on critical data points.

 

When you get down to it, most of your paper should detail possible errors, corrections and means to mathematically confirm those corrections. They will not accept anyones word on any aspect.

Edited September 14, 2016 by Mordred

[MrMaker]

I am about to sign a cooperation agreement with the top geodezist and geophysics in Hungary and I will point them to this forum to review the suggested ideas.

 

That's great. You should also seek the support of a good optical physicist. He can help you with the whole refraction and dispersion issues.

 

 

"Regarding the board, I wouldn't use a semi-transparent material anymore.

I have only one concern: that the camera from the starting position is probably not going to be able to capture the beam on the boar all the way (we plan to do 10kms next time). In this case we can have a camera on the opposite shore, but that will not see the laser hit if the board is not transparent. We might as well use a camera in a boat that is following the measurement boat from the side.We will have a camera onboard facing the board to make the exact readings, but we can confirm the position only with timecode (that may not be well proved).

We have to check now in a test if an opal surface or a retroreflective surface (like a moviescreen) is better to capture the beam.

Please tell me your opinion on all this.

 

 

As mentioned by Mordred, the more the better. You should have a static (in relation to the boat) camera pointing to the board. The camera on the shores are good only to "prove" that you are not fabricating data to the most skeptic ones, and you should keep using that. Your idea of an additional boat making extra measures is great, as you can keep one pilot in the "board boat" and the rest of the crew and measuring tools in the other boat.

 

Regarding time and distance readings, the GPS and Clock from the camera at the "board boat" should be enough. Again, if you are concerned about proving to others that you are not fabricating data, just film and document the whole thing, like you did before. Double check all info before publishing to avoid misunderstandings.

 

Finally, regarding the material - opaque or reflective - maybe you need additional POCs to find out what is better. What matters is that you should be able to clearly and easily find the limits of the beam spot. I think that measuring it after it went trough a semi-transparent material may cause small disruptions, but maybe I am being too cautious.

 

About the movement of the laser beam: it was noticed only at the measurements upto midnight.

The beam was moving ONLY sideways! It looked like someone was moving it on purpose, an unusually high horizontal vibration: quite high frequency and movement. I would like to attach a video here but I can't - can someone give me an idea how to?

What could be the purpose of the only sideway movement? (at this time the laser was at 50cms 4.1 feet)

 

 

I have no idea how it can move only sideways. Like I mentioned before, these refraction behavior that you saw there would be a very interesting paper all by itself

 

Important to notice is that I think you saw that only during the night because it was more visible at that time. Maybe it was also happening during the day.

 

Anyway, you need to find a way to control that, and if it's not possible to control, you will need to measure that. If this is happening, you will need your boat to be static (as much as possible) and measure several times during some 2min.

 

We've been talking about measuring this or that, but I would say you need to document first and measure later. Mordred's suggestion of a "reference grid lines both horizontal and vertical" should be strongly considered.

 

 

 

We will definitely put the laser higher next time and use a big enough board to measure the beam. Bigger boat is not a problem, we can have powerboat, or a sailing boat with engine. The sail is a huge but not an ideal recording surface (in no wind conditions of course).

 

The beam dispersion can be automatically validated if the board is functioning well. The board would be the best indicator for refraction as well.

 

Water and air temperature measurements are quite hard to accomplish with the moving boat. I am not sure how we can make that accurate.

 

 

That's great that you have the resources. Consider the stabler boat you can find.

 

Also, take Water and Air temperature readings with no movement from the boat. You shouldn't measure anything while the boat is moving, or you will need also to add all the speed and small inclinations to the board readings to the data set, adding unnecessary complexity.

 

Finally, I don't think the board will be the best indicator for refraction. The board may help you with the refraction analysis, but it will not indicate the refraction all by itself.

 

 

 

Perpendicular and measured board (the height of the board may be varied here to match the exact height from water surface - the exact height is still a question so it is 1.5 on the picture for now)

 

14316030_10207009617380248_1353893171_o.png

 

 

 

I didn't get this point exactly, sorry.

 

You need a board that goes all the way from the bottom of the boat to 5m or 10m. You don't want to move the board up during the experiment (I didn't understand if that's what you want to do) or to have the board starting at 1.5m.

 

And please go through Mordred list of suggestions in post #127, they are very very interesting.

 

Thanks again for all the answers

Edited September 14, 2016 by MrMaker

[Mordred]

Lets run a simple example of data to gain mathematical proof. Test

 

laser hitting a backboard. What is the angle of the backboard to the laser?

 

Well we can use the reflection angle and the incoming angle of the laser to confirm the relation of the backboard to the laser.

 

Good ole Pythagoras...

 

This is what you want to do at every measurement point. We can take this further to assist in refraction.

 

Establish a coordinate system

 

For the test your looking at, you have a couple to choose from. If you want a Flat coordinate system use 3d Cartesian coordinates where Pythagoras holds true between two reference points.

 

[latex]x^2+y^2+z^2 [/latex]

 

If you want the metric for a curved metric use polar coordinates.

 

So we have defined our metric. Now lets start modelling our atmosphere. Ideal gas law applications. (density, pressure,temperature,humidity,chemical composition) Lets start with density

 

Well again we have another choice. Static or dynamic distribution. Static works well if there isn't any inherent direction of motion. (wind).

so we can use the above metric for a Flat and static distribution. A uniform distribution (homogeneous and isotropic) will be

[latex]\rho_x^2+\rho_y^2+\rho_z^2[/latex]

However this isn't the case. The lower elevations has a higher density to the higher elevations. We have an inverse relation. So we show this relations along the y axis. As were only dealing with elevation change.

If you plot the change at each y coordinate you can establish the rate of change at each elevation.

 

(As were static we don't need the vector direction we only need the magnitude.)

 

this rate of change will depends on the other factors mentioned above as well as good ole gravity.

These are just starting steps to model atmospheric refraction.

 

I hope you can start to see the kind of mathematical detail a good paper will include... This detail such as the first example can help eliminate measurement errors and uncertainties. Via differential geometry...

 

When you apply the refraction formulas, you apply them under a metric with corrections due to the degrees of freedom inherent of an ideal gas. Added degrees of freedom include temperature, pressure, humidity, chemical composition. (though the latter two can argued one and the same) depending on modelling choices.

Edited September 14, 2016 by Mordred

[Sandor Szekely]

I will answer the above posts in the morning, thanks for sharing the thoughts!

I found a way to present the videos here - I uploaded them to my google drive and share the path here

https://drive.google.com/open?id=0B2gyF12ygRBjT1NVYmMzREplTEU

Here is the "Balaton laser reflexion" folder
This was the experiment at dawn, when the laser hit the water surface at around 1500 meters from the shore.
As I checked now this was the very same measurement where we had the horizontal vibration of the beam: so the solution is that the water surface was reflecting it like a vibration. Good to know that laser vibration points to reflexion problem.

The name of the files contain the date and time stamp (Samsung videos and pictures that contain GPS as well)
The "famous" picture from the Canon 650d 1200mm (400x2x1.6crop) teleobjective. First it was obvious that we see a huge refraction, but than we found that it is only the distorsion of the teleobjective lenses. In reality it was a straight line hitting the water at a 0.016 degrees (yube film at 6:35) angle that we did not notice on board.

4:51:50 picture shows the beam
4:52:29 video shows the laser beam before hitting the water - note how collimated is the beam before hitting the water.

5:00:24 picture shows the beam on the board with some distorsion - note that here the beam is already reflected on the water surface (GPS pos on the pic)
5:00:34 video shows the beam on the board looking like an amoeba - this is the effect of water reflextion

5:06:46 picture with GPS
5:07:13 video shows the vibrating laser beam reflected on the surface (that is why it is horizontal)

5:10:34 video shows some more laser beam swinging
5:10:58 picture GPS

5:29:57 video is showing the way back. The beam is not a direct hit at longer distances but from closer we can see the direct beam again.

I include moere pictures, as well RAW picture files from the Canon

for these pictures here I write the exact time of photo taken - note how interesting that the pictures are nearly taken at the same time from slightly different distances from the laser at position A. some pictures show a straight line while others are curved

DSCN 1897 at 4:08:10
DSCN 1898 at 4:08:30
DSCN 1899 at 4:09:00
DSCN 1900 at 4:09:40
DSCN 1904 at 4:10:28
DSCN 1905 at 4:10:44
DSCN 1906 at 4:11:16
DSCN 1907 at 4:11:30
DSCN 1908 at 4:11:58

DSCN 1953 at 4:54:26 Sunrise
DSCN 1971 Sun with clouds
DSCN 1980 at 4:58:18 Boat arrives back to position A

I am interested on your comments on this 3rd measurement. The laser was at 50cms 4.1 feet above water, the air temp was very cold like 16C.


this is the animated 1200mm teleobjective perspective

Yes the evaperation ducting can cause a huge number of optical problems. Even having multiple potential laser paths.

This can easily cause motion in every direction with a preferred direction due to wind movement. (think of the effect moving water can have). In the evaperation duct the humidity approaches 100% as you approach the water surface.

During the test. If possible

at each point record the temperature, at laser elevation and surface water temp. humidity, and wind speed and direction. Ideally the atmosphere chemical composition would also be useful. Oxygen, nitrogen, carbon dioxide %, etc is useful data for location refraction values.

The atmospheric pressure is also needed to fine tune calcs. This data can be used to further analyze your dataset.

Also include the technical datasheet for the equipment your using. (ie the laser.. ). The emitted wavelength etc is important...

In terms of beam dispersion, the evaperation duct can easily increase the beam radius. (extremely easy)

I would recommend on your backboard you have reference grid lines both horizontal and vertical. This way we remove the need to pixel count etc the beam radius from photos etc.

Remember the more data you provide, the greater your accuracy becomes. It also reflects diligents to important potential influences and steps to mitigate or acccount for their influence. For example if you sample the above list at each point. You can fine tune refraction data at each measurement point. ( physicists studying your paper, just love these details).

Of course they will also want to see your calculations. (To that end, I'm still putting together the list of formulas with correction formulas for locality).

Its quite intense...

Remember a good paper, will contain sufficient data, that doesn't require studying a photograph etc.

1) Appropriate formulas
2) accurate data, the more measurement data the better
3) A detailed list of possible measurement errors and the corrections. (including the related calculations that the corrections are effective)
4) good reference papers, including previous studies.

There is a rule of thumb, physicists usually only accept mathematical proof, that corrections are in place... They won't accept a verbal only description. Nor will they take anyones word that corrective measures are in place. Unless they can mathematically confirm the corrective measures...

For example an image isn't sufficient. What distortions are inherent to the image?

Just a side note, personally if I'm studying a paper proposing a new model and datasets. I personally won't accept any paper that doesn't include a detailed list or error margins on critical data points.

When you get down to it, most of your paper should detail possible errors, corrections and means to mathematically confirm those corrections. They will not accept anyones word on any aspect.

How can I measure the height of this ducting zone? Or to what humidity % level should I look for?

I have a concern how I can make accurate environmental measurements at each point. Do I have a fast way to determine the values quickly? The distance of 10kms takes about 1.5 hur in one way + the measurement stops - this might extend the timeframe very much. Is there a datalogger precise, all functions included and fast enough? Please advise
I'd like to collect more data too, you are right it makes the measurement more precise and understandable

"I would recommend on your backboard you have reference grid lines both horizontal and vertical."
This is correct, we'll do so

Agreed with all points 1 to 4
this is a very good idea - I haven't made now but important
"a detailed list or error margins on critical data points."

Edited September 14, 2016 by Sandor Szekely

[snaphat]

WE have no error at the slope correction laser leveling. Mick was wrong and instead of admitting it he banned me from metabunk (for "trolling").

We proved in the autocad video that his 118.5 cms leveling theory will result a 3.19 meters beam height instead of the 3.45 meters (not a significant difference).

 

I answered to Mick's comments until I was not kicked from meta. I will not answer them again, as you copy pasted them here, PLS copy paste my answers too.

 

Thanks for sharing the meta calculator, but I am banned from meta. (reason: I am trolling... can someone explain me how I can be trolling on my own thread?)

 

so Mick case is closed, I am not debating with him. (unless he is here)

 

You were banned for lying about being in contact with the folks from the 2013 LIDAR experiment you referenced in your OP here, misrepresenting their experiment; as well as for your claim that they told you their results showed the lake was flat (as opposed to equipotentially level over the curve of the earth). Mick contacted the lead author and the author said he had no contact with you and that the results followed the curve of the earth; ergo, what you said to everyone on the other forum is very troubling, dishonest, and against the forum rules.

 

Your OP here similarly misrepresents/misleads regarding the authors' work seemingly as if you were involved, that they showed the lake was flat (or "truly level" under the definition of 'truly level' meaning flat), and that their experimental data agrees with yours. You were not involved in their experiment; nor does their data agree with your data. Your data indicates the lake surface is flat, where as, their data indicates a level surface following the curve of the earth. Again, the lead author of the 2013 LIDAR experiment stated the latter in correspondence with Mick. Misrepresentation of other authors' work is extremely troubling and academically dishonest.

Edited September 15, 2016 by snaphat

[Mordred]

How can I measure the height of this ducting zone? Or to what humidity % level should I look for?

 

 

 

Probably the easiest way is to find the effective Earth radius.."k" I'll try to run you through the calculations..

 

First what is the Effective Earth radius ? well its a hypothetical radius where the curvature path of our signal matches the curvature of the Earth. For our situation we can ignore variations in chemical composition and use the refractive index of air as unity value 1. Its extremely close... So what we now need is the refractive index. For the refractive gradient we define a new unit capital N.

 

[latex]N=(n-1)*10^6[/latex]

 

[latex]k=\frac{1}{(1+a\frac{dn}{dh})}[/latex] when k=-157 N units/km the ray path and the effective Earth path effectively match. The ray follows the curvature of the Earth. Your three main zones can be distinquished by values of k.

 

This site covers the basic fundamentals but a key formula on this link is

[latex]N=77.6\frac{P}{T}+3.37*10^5\frac{e}{T+2}[/latex] the left hand side of the + sign is dry term, the right hand side the wet term.

 

the water vapor vapor pressure "e" can be calculated via

 

[latex]e=H*\frac{6.11121exp(\frac{17.502t}{t+240.97}}{100}[/latex]

 

where H is the relative humidity %, t is temp in degrees celcius (careful some of the other formulas use kelvin), e_s is the saturation vapor pressure in hPa

 

http://www.mike-willis.com/Tutorial/PF6.htm

 

its a basic tutorial. It doesn't detail the regions well. The different refractive conditions can be characterize by the following

 

using k and the effective earth radius value -157 N/km normal air conditions

[latex]k=\frac{1}{(1+a\frac{dn}{dh})/157}[/latex]

 

here dn/dh is roughly -39 N/km which equates to roughly k=4/3

 

subfraction is [latex]4/3> k> 0[/latex] superfraction [latex]\infty>k>4/3[/latex]

 

Ducting is [latex]\infty<k<0[/latex]

 

this is where your evaperation duct conditions lie within. For the duct height we need to correlate the frequency aspects the link sort of hints that lol. under roughing ( you will need the laser frequency)

Edited September 15, 2016 by Mordred

[studiot]

Sandor,

 

I am sorry you have decided to reject my suggestions since they are based on sound principles that carry enormous weight in all walks of experimental science.

 

The most powerful and persuasive experiments are those that have corroboration by independent measurement ie measurement by other means.

 

This is what I was offering you.

 

Earlier in the thread you stated that you have a mathematics degree, and yet you asked me about interpolation v extrapolation.

 

Interpolation is all about working from the whole to the part.

Establishing control or reference points outside and perhaps throughout your working region.

This is true in large scale physical surveys and abstract finite element analyses.

 

And this is what you are lacking here.

 

The proper establishment of a few control points on a traverse would set any measurements on a proper footing and reduce the fancy corrections and corrections on corrections Mordred proposes to an academic exercise (sorry Mordred).

 

This is basically a simple exercise and with proper methodology it could be a tight and accurate survey.

 

A final suggestion. I am not sure you appreciate the difference between distances on maps, the geoid, the spheroid, the gps system and in actual measurements.

They are all different and it is important to avoid offering figures from one system that were made in another.

[Mordred]

 

The proper establishment of a few control points on a traverse would set any measurements on a proper footing and reduce the fancy corrections and corrections on corrections Mordred proposes to an academic exercise (sorry Mordred).

 

No need, there are far easier and more reliable means to measure a lake level than optics. There is also ways to reduce the corrections by good control points as well as reliable reference points. LOL back to that whole multi-laser idea it can be used as a control point but the math may or may not be simpler. Ideally we always prefer to eliminate the need for the corrections.

Edited September 15, 2016 by Mordred

[Sandor Szekely]

 

You were banned for lying about being in contact with the folks from the 2013 LIDAR experiment you referenced in your OP here, misrepresenting their experiment; as well as for your claim that they told you their results showed the lake was flat (as opposed to equipotentially level over the curve of the earth). Mick contacted the lead author and the author said he had no contact with you and that the results followed the curve of the earth; ergo, what you said to everyone on the other forum is very troubling, dishonest, and against the forum rules.

 

Your OP here similarly misrepresents/misleads regarding the authors' work seemingly as if you were involved, that they showed the lake was flat (or "truly level" under the definition of 'truly level' meaning flat), and that their experimental data agrees with yours. You were not involved in their experiment; nor does their data agree with your data. Your data indicates the lake surface is flat, where as, their data indicates a level surface following the curve of the earth. Again, the lead author of the 2013 LIDAR experiment stated the latter in correspondence with Mick. Misrepresentation of other authors' work is extremely troubling and academically dishonest.

SNAPHAT

behave your self!

and prove if you have such a claim!

 

This is my only and last comment about METABUNK

I am not going to answer anybody who does not respect me

(I am disappointed to see the metabunk and fb trolls showing up here too)

 

"You were banned for lying about being in contact with the folks from the 2013 LIDAR experiment you referenced in your OP here"

NOPE

I have been banned for trolling! (how can I troll on my thread? hmm)

WHY I can not upload any files / pictures here? AM I restricted? (just like at meta...)

 

I HAVE NEVER SAID ANYWHERE THAT I AM IN CONTACT WITH THE PEOPLE WHO MADE THE 2013 LIDAR EXPERIMENT!

(INDEED I said I will not give my contact details until I have not signed the cooperation agreement)

 

"misrepresenting their experiment;"

DID I ? exactly where? this is a lie too

 

"Mick contacted the lead author and the author said he had no contact with you"

 

YES! Mick from metabunk DID contact him and made me a BIG SHAME! I spoke with Andras Zlinszky SINCE THEN! and cleared the missunderstanding that MICK MADE CONFUSION!

I think he did this on puprose.

MICK LIED to me : he said he did not ask about me, just the experiment : it's a LIE!

 

SO to make it clear for you and other people reading this:

 

I never said I am in contact with Andras Zlinszky.

I have not even knew about the LIDAR experiment until GivemeClouds (as I remember) shared this document!

I spoke with Andras 2 days ago, when I realized that Mick was contacting hi to make confusion.

 

I AM in contact with university in Hungary since I said so - BUT I WILL NOT GIVE ANY DETAILS OR MY CONTACTS

I think you can understand it after that creepy move from MICK WEST)

 

 

"Your OP here similarly misrepresents/misleads regarding the authors' work seemingly as if you were involved,"

 

QUOTE HERE where exactly I said I am INVOLVED in the LIDAR experiment?

 

THESE ARE SERIOUS CHARGES ON ME!

 

I'd like the moderator to decide and give opinion : if this is a normal conversation style here from Snapshot, than sorry I will NOT be able to participate in such a debate

 

"Misrepresentation of other authors' work is extremely troubling and academically dishonest."

Edited September 15, 2016 by Sandor Szekely

[imatfaal]

!

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[studiot]

Here is an worked example of pure simplicity and accuracy for the Institute of Structural Engineers levelling in a similar situation.

 

Please read the sections in the order 1,2,3 I have labelled on the left hand margin as I have cobbled together from several pages.

 

[Sandor Szekely]

Here is an worked example of pure simplicity and accuracy for the Institute of Structural Engineers levelling in a similar situation.

 

Please read the sections in the order 1,2,3 I have labelled on the left hand margin as I have cobbled together from several pages.

 

level3.jpg

yes I undertand that the light we see gives an apparent image and not the real position of the object.

 

this caught my attention:

"assuming no change in refraction"

 

this is what I am pointing out, that refraction is not a constant but a continuocly changing index (? not sure about the correct term here)

so we can evaluate a picture at an exact moment (with sufficien ambient data) but we can not use this momentary refraction as a constant in terresterial refraction calculation.

 

Here I'd like to ask a question about a semi - related subject. (refraction)

The sun is not where we see it: we see an apparent sun and the only observer who sees the real sun has it 90 degrees overhead.

 

I'd like to attach a picture here, but I am restricted on any attachments to my comment! - why is that?

 

Is there a formula to correct for the sun true position from the specific observer positions angle?

 

I read about the reciprocal leveling in your attached image. This would be a good idea but the boat is not a stable position so we can't like shoot a laser backwards to position A.

We tried this and we had a "backwards hit", but this is not a stable position so it takes time to get a direct hit. I'd like to add pictures to this as well, but I can not... this makes explanation quite hard.

My question:

Is there a triangulation leveling method, that uses multiple positions to get the most accurate height reading on the object?

As here was suggested before too, I am going to use different methods in the upcoming experiment. I could place a theodolite in a different position than A, let's say like from a side view on the island there. (picture would be great here too...)

Do you have any setup in mind that would make the measurement more precise with using different techniques in different positions as well?

[imatfaal]

...

 

I'd like to attach a picture here, but I am restricted on any attachments to my comment! - why is that?

 

 

 

http://www.scienceforums.net/topic/73369-uploading-images/

 

You can only attach some file formats - stick to PNGs and JPGs

[Sensei]

I HAVE NEVER SAID ANYWHERE THAT I AM IN CONTACT WITH THE PEOPLE WHO MADE THE 2013 LIDAR EXPERIMENT!

(INDEED I said I will not give my contact details until I have not signed the cooperation agreement)

 

"misrepresenting their experiment;"

DID I ? exactly where? this is a lie too

 

I am quite confused..

In the initial thread post there are:

 

"we would like to introduce you our laser curvature experiments."

 

"We are looking for the curvature on the surface of the lake Balaton in Hungary (...)"

 

"We have conducted a series of experiments (...)"

 

Repeated dozen times "we".

"We" for us, means "you plus some people from your team"...

 

At the same time Boxer said in post #60

"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 15, 2016 by Sensei

[studiot]

 

Sandor Szekely post#121

Standard refraction used in geodezical terrain measurements is 0.4 millimeter / kilometer. Dubble run leveling in 1999 by Swiss authors I have to look for that link)

 

 

Er No.

 

The problem is that I don't think you understand the surveying theory.

 

I seriously doubt that the Swiss authors were referring to a standard correction as we are discussing.

Since they mention double run leveling, they are talking about calculational adjustments to a leveling network.

 

I make the refraction correction 11mm not 0.4mm at an observational distance of 1000m

 

Here is a proper Swiss discussion, including a table which includes refraction and curvature corrections.

Note carefully their value at 1km. They make the refraction correction 9mm using a slightly lower value of refraction that the international standard constant of 0.07, but still very close to my calculation.

This is taken from the Swiss manufacturer's textbook

The Theodolite by Wild of Heerbrugg Switzerland.

 

 

This lack of surveying knowledge may also have lead to you abrupt response to my posts on reciprocal levelling (post#137) and the previous one (post#133) on survey control points.

 

This is why I keep recommending obtaining the services/advice of a professional surveyor.

Edited September 15, 2016 by studiot

[Sandor Szekely]

 

I am quite confused..

In the initial thread post there are:

 

"we would like to introduce you our laser curvature experiments."

 

"We are looking for the curvature on the surface of the lake Balaton in Hungary (...)"

 

"We have conducted a series of experiments (...)"

 

Repeated dozen times "we".

"We" for us, means "you plus some people from your team"...

 

At the same time Boxer said in post #60

"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."

Okay I give the definition for "we" used in the above text.

 

WE as:

Leader of the experiment: Sandor Szekely

My partners in developing and evaluating the experiment: Zack M'rabbet (AutoCad and film), Steve Torrence (3D animation)

 

Special guests on the experiment: Dave Moor and Nicu Buricu

 

Laserist Mina (goldlaser.hu) and her employee

Sandor Szemendri, the captain of theBoat and some other people.

 

laser curvature experiments, as this was nr.2 as title of the video. We had a pre-test measurment 1 month before (video on the same channel)

We will continue to make more measurments (improved with ideas from here as well) on the lake Balaton and over land also.

 

EDIT here to make it more clear: This section above is "we".

this next section is the theoretical expansion of the "we" in the future:

 

We will more likely work together with a university - if that cooperation agreement is signed I will proudly present it.

I have spoken with the leader of the LIDAR experiment 2 days ago - as I heard that he had been disinformed. (He is not even working at the same university as I am in contact with.) He told me that he will send me the complete (open access) database of the very same route LIDAR measurement as we had in our experiment. I will share for evaluation here as soon as I have them.

As his office is located near the site of the experiment he said he might be able to visit us on the next upcoming experiment.

 

We always announce our experimental dates and locations and we WELCOME everybody who has the possibility to visit us.

Edited September 15, 2016 by Sandor Szekely

[Mordred]

nice procedure on that survey paper.

[Sandor Szekely]

 

Er No.

 

The problem is that I don't think you understand the surveying theory.

 

I seriously doubt that the Swiss authors were referring to a standard correction as we are discussing.

Since they mention double run leveling, they are talking about calculational adjustments to a leveling network.

 

I make the refraction correction 11mm not 0.4mm at an observational distance of 1000m

 

Here is a proper Swiss discussion, including a table which includes refraction and curvature corrections.

Note carefully their value at 1km. They make the refraction correction 9mm using a slightly lower value of refraction that the international standard constant of 0.07, but still very close to my calculation.

This is taken from the Swiss manufacturer's textbook

The Theodolite by Wild of Heerbrugg Switzerland.

 

refract1.jpg

 

This lack of surveying knowledge may also have lead to you abrupt response to my posts on reciprocal levelling (post#137) and the previous one (post#133) on survey control points.

 

This is why I keep recommending obtaining the services/advice of a professional surveyor.

I aggree

 

I will not look for that article of 0.4mm/km as it was probably not the same question we are discussing here. The 11mm volume seems reasonable to me. I only have a worry if the refraction can be estimated or not - as it varies very much in local conditions. The calculation of refraction on each measurement would be preferable as the measurement route is more than 2 hours. Conditions change a lot over time.

 

"This is why I keep recommending obtaining the services/advice of a professional surveyor."

Absolutely aggreed and I am taking that advice

 

[MrMaker]

I will answer the above posts in the morning, thanks for sharing the thoughts!

 

I found a way to present the videos here - I uploaded them to my google drive and share the path here

 

https://drive.google.com/open?id=0B2gyF12ygRBjT1NVYmMzREplTEU

 

Here is the "Balaton laser reflexion" folder

This was the experiment at dawn, when the laser hit the water surface at around 1500 meters from the shore.

As I checked now this was the very same measurement where we had the horizontal vibration of the beam: so the solution is that the water surface was reflecting it like a vibration. Good to know that laser vibration points to reflexion problem.

 

The name of the files contain the date and time stamp (Samsung videos and pictures that contain GPS as well)

The "famous" picture from the Canon 650d 1200mm (400x2x1.6crop) teleobjective. First it was obvious that we see a huge refraction, but than we found that it is only the distorsion of the teleobjective lenses. In reality it was a straight line hitting the water at a 0.016 degrees (yube film at 6:35) angle that we did not notice on board.

 

I saw the "trembling laser" video. That's a bizarre effect indeed. It looks like it's mainly going left to right only, but the light that is hitting the board is "dancing" in on itself. There is a big bright area (around 30cm wide I'd say), but there is also a huge area hitting the board that is even bigger than the board itself. Very intriguing. Do we have any optics nerd here in the forum?

 

Regarding the beam distortions, those are a huge risk to your data set.

 

If something like that happened during the night, there is no way to know what may have happened during the day. With this new information, I would say that you need to measure the beam spot every 100m or so. 500m may not be enough. It's too much refraction, reflection or whatever optic distortion is going on there, to guarantee the accuracy of the data.

 

Different doubt though: you mentioned reflection, but that would mean that the laser hit the water at one point, is that correct? If that's the case, the laser was either pointing downwards or the crazy refraction effects forced it downwards.

 

Are you taking notes of all Mordred's, Stu's, mine and others' suggestions? That's quite a lot

[michel123456]

Okay I give the definition for "we" used in the above text.

 

WE as:

Leader of the experiment: Sandor Szekely

My partners in developing and evaluating the experiment: Zack M'rabbet (AutoCad and film), Steve Torrence (3D animation)

 

Special guests on the experiment: Dave Moor and Nicu Buricu

 

Laserist Mina (goldlaser.hu) and her employee

Sandor Szemendri, the captain of theBoat and some other people.

 

laser curvature experiments, as this was nr.2 as title of the video. We had a pre-test measurment 1 month before (video on the same channel)

We will continue to make more measurments (improved with ideas from here as well) on the lake Balaton and over land also.

 

EDIT here to make it more clear: This section above is "we".

this next section is the theoretical expansion of the "we" in the future:

 

We will more likely work together with a university - if that cooperation agreement is signed I will proudly present it.

I have spoken with the leader of the LIDAR experiment 2 days ago - as I heard that he had been disinformed. (He is not even working at the same university as I am in contact with.) He told me that he will send me the complete (open access) database of the very same route LIDAR measurement as we had in our experiment. I will share for evaluation here as soon as I have them.

As his office is located near the site of the experiment he said he might be able to visit us on the next upcoming experiment.

 

We always announce our experimental dates and locations and we WELCOME everybody who has the possibility to visit us.

Nice!

 

I saw the "trembling laser" video. That's a bizarre effect indeed. It looks like it's mainly going left to right only, but the light that is hitting the board is "dancing" in on itself. There is a big bright area (around 30cm wide I'd say), but there is also a huge area hitting the board that is even bigger than the board itself. Very intriguing. Do we have any optics nerd here in the forum?

 

Regarding the beam distortions, those are a huge risk to your data set.

 

If something like that happened during the night, there is no way to know what may have happened during the day. With this new information, I would say that you need to measure the beam spot every 100m or so. 500m may not be enough. It's too much refraction, reflection or whatever optic distortion is going on there, to guarantee the accuracy of the data.

 

Different doubt though: you mentioned reflection, but that would mean that the laser hit the water at one point, is that correct? If that's the case, the laser was either pointing downwards or the crazy refraction effects forced it downwards.

 

Are you taking notes of all Mordred's, Stu's, mine and others' suggestions? That's quite a lot

I don't know about this effect. What I know is that when you use a laser parallel and very close to a shiny surface you can get strange results. The slightest deviation gives you reflections from the shiny surface (in this case, the lake).

Edited September 15, 2016 by michel123456

[studiot]

 

michel123456 pots#146

I don't know about this effect. What I know is that when you use a laser parallel and very close to a shiny surface you can get strange results. The slightest deviation gives you reflections from the shiny surface (in this case, the lake).

 

 

Yes indeed.

 

Some while back I bought the first (in the UK) of the new generation of alignment lasers from Sweden and used it to check for movement of culverts under UK motorways.

 

Before deployment I thoroughly tested its leveling and beam collimation capabilities.

I was suprised to note that the beam (spot) diameter varied from less than 10mm to around 35mm and back again over a not quite periodic distance.

This was OK as I could get the whole beam on a vertical scale and measure the centre point by difference.

And yes there was some illumination noise from reflections from the walls, soffit and floor of the culverts.

 

Sandor please note that this measurement exercise was carried out by interpolation, not extrapolation as you are using.

 

Sandor, since you are approaching a University for assistance, and you like photographic methods, you may be able to access equipment for horizontal photogrammetry through them.

Wild and Leica make special cameras for this.

 

I have not noticed any poster so far properly using measurements on photographs. The science of photogrammetry is all about , using photographs for measurements in up to three dimensions, or even four if you include time.

 

The above mentioned equipment for instance, was used to study the stability of the rock face below Edinburgh Castle and I used similar equipment to monitor the stability of the North Somerset Coastal Cliffs, where they support the A39 trunk road.

 

But I could imagine this equipment also being used for your task.

[Klaynos]

My masters was in optics, my PhD relief heavily on it. Swansont uses lots of optics everyday. So there are people around who can comment.

 

I'd need to see a diagram of your optical set up and specs of the laser.

 

For this kind of experiment there are lots of things that are going to mess with you. Ducting, scatter from turbulence, lack of collimaton, movement of the source or optics...

[studiot]

Readers should also be very careful of another point concerning vertical heighting by optical equipment.

 

All optical equipment is mounted on something and therefore at some height above the actual point on the ground or water that is being measured.

 

All surveying work reckons distances vertically and horizontally between these points on the ground.

 

There are two basic methods for correcting this.

 

1) Corrections to the angles.

 

2) Corrections to the distances deduced.

 

It should be clearly stated which method is employed.

 

Further the actual heights of the equipment should be made plain.

 

This last is particularly important in intervisibility calculations and was rather hidden in some posters (dark star and Mr Maker I think) otherwise comprehensive data here.

[Mordred]

My masters was in optics, my PhD relief heavily on it. Swansont uses lots of optics everyday. So there are people around who can comment.

 

I'd need to see a diagram of your optical set up and specs of the laser.

 

For this kind of experiment there are lots of things that are going to mess with you. Ducting, scatter from turbulence, lack of collimaton, movement of the source or optics...

 

equipment datasheets are definitely handy. I can also use them to look for some of these affects mentioned. The effect of the elevator duct varies depending on equipment frequencies. Glad to see someone that can help double check the equations involved for this application. I'm going down memory lane on everything involved, in terms of refraction, scatter etc.

 

 

The more I think of this test, the more I keep thinking that two emitters may be a good idea. I keep looking at the pros and cons involved. Assuming parallel transport placement. Safety issues addressed (lol). KEY NOTE use two distinct frequencies.

 

 

 

PROS.

 

1) detection in deviation in parallel transport can be used to find changes in refractive index.

2) if the two lasers are mounted in tandem vertically we can use geometry relations between the two beams to assist in leveling. Combined with a grid backboard we can break the leveling aspects down to straightforward trig. This will help correct leveling errors in 3D if done correctly

3) the changes in frequency and loss of parallel transport can be used to calculate the refraction index. (this in principle is used in equipment today. Usually through a known sample) however a known sample isn't needed just more complex. If not.

 

CONS

1) added equipment and complexity, adds to potential systematic errors

2) greater number of control point data to collect. (measurements between the two laser beams for example, as well as receiving frequencies.)

 

Even without worrying about refraction, etc the advantages in PRO 2 is in my opinion worth the added cons

 

The above may work better if the two lasers were aimed to a common point. Forming two sides of our triangle, this can help in leveling and distance from emitter calcs.

 

(KEY NOTE do not mount the two lasers onto the same mount backboard. We don't want to add material expansion/contraction problems)

Edited September 15, 2016 by Mordred