#### somerled

• 319
##### Re: "Round earth" conspiracy
« Reply #20 on: August 11, 2019, 11:35:16 AM »
[Geodetic

I am unaware that plane survey finds no curve. Citation requested. There's plenty in Geodetic Surveying that suggests otherwise.

Geodetic survey is nothing but the application of spherical trig to plane survey , so enables earth to be mapped on to sphere .

"Geodetic survey considers the earth as a sphere . Planes survey considers  earth as a plane - the approximation being within the permissible error for areas up to about 100 square miles. The former involves knowledge of spherical trigonometry ."

From the introduction in the book " Elementary surveying " by Arthur Lovat D.Sc , A.R.C.S., A.M.Inst.C.E.
University reader in Civil Engineering at the University of London published in 1946. Page 1.

https://en.wikipedia.org/wiki/Surveying#Plane_and_geodetic_surveying
You can see that even Wiki acknowledges this 100 mile square area in which earth is mapped as a plane .

The fact is , if trigonometric survey - which requires no assumption of shape of the area under scrutiny - finds no curve over 10 miles ,  then there is none unless it is so small that it cannot be accounted for within instrument error .

#### stack

• 1452
##### Re: "Round earth" conspiracy
« Reply #21 on: August 11, 2019, 05:57:09 PM »
[Geodetic

I am unaware that plane survey finds no curve. Citation requested. There's plenty in Geodetic Surveying that suggests otherwise.

Geodetic survey is nothing but the application of spherical trig to plane survey , so enables earth to be mapped on to sphere .

"Geodetic survey considers the earth as a sphere . Planes survey considers  earth as a plane - the approximation being within the permissible error for areas up to about 100 square miles. The former involves knowledge of spherical trigonometry ."

From the introduction in the book " Elementary surveying " by Arthur Lovat D.Sc , A.R.C.S., A.M.Inst.C.E.
University reader in Civil Engineering at the University of London published in 1946. Page 1.

https://en.wikipedia.org/wiki/Surveying#Plane_and_geodetic_surveying
You can see that even Wiki acknowledges this 100 mile square area in which earth is mapped as a plane .

The fact is , if trigonometric survey - which requires no assumption of shape of the area under scrutiny - finds no curve over 10 miles ,  then there is none unless it is so small that it cannot be accounted for within instrument error .

In the book you cited above, I suggest you read the chapters on "Leveling" and "Angular Leveling". It gives you all of the ways and instruments used to determine curvature over distance. From plumb line leveling to bubble leveling, etc. Interesting stuff. And quite comprehensive as to the manners surveyors have used for decades if not centuries.
Not much is known about the celestial bodies and their distances.

#### somerled

• 319
##### Re: "Round earth" conspiracy
« Reply #22 on: August 12, 2019, 02:14:53 PM »
Where is the relevance ? No detectable curve anywhere in plane surveying up to 100 square mile area. Where is this addressed . Adding spherical trig to plane survey does not change a plane into a curved surface. Be specific .

#### stack

• 1452
##### Re: "Round earth" conspiracy
« Reply #23 on: August 12, 2019, 05:45:43 PM »
Where is the relevance ? No detectable curve anywhere in plane surveying up to 100 square mile area. Where is this addressed . Adding spherical trig to plane survey does not change a plane into a curved surface. Be specific .

Where does it say, "no detectable curve..."? That's not what it says at all. It says:

"Plane surveying assumes the earth is flat. Curvature and spheroidal shape of the earth is neglected. In this type of surveying all triangles formed by joining survey lines are considered as plane triangles. It is employed for small survey works where errors due to the earth's shape are too small to matter.[14]

In geodetic surveying the curvature of the earth is taken into account while calculating reduced levels, angles, bearings and distances. This type of surveying is usually employed for large survey works. Survey works up to 100 square miles (260 square kilometers ) are treated as plane and beyond that are treated as geodetic.[15] In geodetic surveying necessary corrections are applied to reduced levels, bearings and other observations."

What it's saying is that for the most part the type of surveying performed is dependent on the size and scope of the job, so to speak.

Again, read the first few pages in the chapter on 'Leveling' in the book you cited. (Chapt. 5, page 60) There are 3 types of level surveying: Differential (Gravitational), Trigonometric, & Barometric. Differential (Gravitational) being the most accurate. It doesn't simply take a plane state map and apply math to it. It's an actual survey where you measure contours, slopes, altitudes as well as and in respect to measuring the curvature of the earth. If you can understand the tools used, you can understand how they directly measure curvature.
Not much is known about the celestial bodies and their distances.

#### somerled

• 319
##### Re: "Round earth" conspiracy
« Reply #24 on: August 13, 2019, 09:45:42 AM »
I can see you are having a difficult time digesting the fact that surveyors/civil engineers do not account for curvature and consider , not assume , earth to be a plane up to some arbitrary 100 square mile area .

The methods of plain survey do not find curve . Gravitational survey uses the assumption that some magical force acts towards the centre of mass of an assumed spherical body .

#### AllAroundTheWorld

• 3312
##### Re: "Round earth" conspiracy
« Reply #25 on: August 13, 2019, 10:09:07 AM »
I can see you are having a difficult time digesting the fact that surveyors/civil engineers do not account for curvature and consider , not assume , earth to be a plane up to some arbitrary 100 square mile area .

Do you regard that as significant? One thing people seem to struggle understanding is that models can be simplified and still be useful. In A-Level mechanics you don't take things like wind resistance into account when calculating the path of bodies falling under gravity. For most objects of a certain mass you're still going to get results close enough to be useful. For some applications you might need to take other things into account of course, it depends what you're doing. The scale of the earth is such that for many practical things one can consider it flat in calculations and still get results which can be used, just like for most calculations relativistic effects are ignored because it just complicates the calculations and the results from Newton's equations are accurate enough to be usable.

Quote
The methods of plain survey do not find curve . Gravitational survey uses the assumption that some magical force acts towards the centre of mass of an assumed spherical body .

I'm always bemused that gravity is sneered at as some "magical force" by people who believe in UA which is presumably powered by some "magical force"...
If you are making your claim without evidence then we can discard it without evidence.

Nearly all flat earthers agree the earth is not a globe.

#### stack

• 1452
##### Re: "Round earth" conspiracy
« Reply #26 on: August 13, 2019, 05:42:21 PM »
I can see you are having a difficult time digesting the fact that surveyors/civil engineers do not account for curvature and consider , not assume , earth to be a plane up to some arbitrary 100 square mile area .

The methods of plain survey do not find curve . Gravitational survey uses the assumption that some magical force acts towards the centre of mass of an assumed spherical body .

I can see you did not do the reading in the book you cited that I asked you to do. It would help your understanding of the subject if you did.

It's not that the methods of plane survey do not find curve. It's that they are not measuring for a curve. Hence the name, "plane" survey. Earth's curve is irrelevant to what is trying to be accomplished. And actually, Gravitational Surveying (aka Differential Leveling) doesn't assume anything. If you had read the chapter on leveling, you would understand this. Placing two instruments far enough apart with spirit levels leveled (bubble in the middle) pointed at each other will not be pointing directly, horizontally at one another. Each will be pointing slightly upward with respect to each other. From there, you can calculate your curve.

You wouldn't even have to know gravity exists, the bubbles do the work for you.

Not much is known about the celestial bodies and their distances.

#### somerled

• 319
##### Re: "Round earth" conspiracy
« Reply #27 on: August 14, 2019, 01:50:35 PM »
That little drawing shows why no buildings could be built parallel to one another using the principle of gravity acting toward the centre of mass . Do you understand that principle ?

We actually should see that a city 10 miles across , but there again civil engineers know there is no curve over that area so we don't

#### stack

• 1452
##### Re: "Round earth" conspiracy
« Reply #28 on: August 14, 2019, 06:52:34 PM »
That little drawing shows why no buildings could be built parallel to one another using the principle of gravity acting toward the centre of mass . Do you understand that principle ?

We actually should see that a city 10 miles across , but there again civil engineers know there is no curve over that area so we don't

Where does it say, "civil engineers know there is no curve over that area...."? I can't find that. I do see that for most applications curvature isn't an issue that has to be contended with over that area. For example, two 10 story buildings, 10 miles apart, the tops of the building would be tilted away from each other by approximately 0.1447o. Does that microscopic amount matter to the civil engineer?
Not much is known about the celestial bodies and their distances.

#### paulmarkj

• 1
##### Re: "Round earth" conspiracy
« Reply #29 on: August 14, 2019, 07:44:31 PM »
I found this forum because I made a search that found this specific thread. It looked very promising:

---'How, do you think, is the "round earth" conspiracy working? How is it kept a secret? How does the conspiracy hire new people? How many people 'know' the 'truth'? Why hasn't it leaked yet?'

It is an immensely important question, but it has denigrated into yet another detailed question about trig and engineering, eg:

[Geodetic

I am unaware that plane survey finds no curve. Citation requested. There's plenty in Geodetic Surveying that suggests otherwise.

Geodetic survey is nothing but the application of spherical trig to plane survey , so enables earth to be mapped on to sphere .

"Geodetic survey considers the earth as a sphere . Planes survey considers  earth as a plane - the approximation being within the permissible error for areas up to about 100 square miles. The former involves knowledge of spherical trigonometry ."

From the introduction in the book " Elementary surveying " by Arthur Lovat D.Sc , A.R.C.S., A.M.Inst.C.E.
University reader in Civil Engineering at the University of London published in 1946. Page 1.

https://en.wikipedia.org/wiki/Surveying#Plane_and_geodetic_surveying
You can see that even Wiki acknowledges this 100 mile square area in which earth is mapped as a plane.
The fact is , if trigonometric survey - which requires no assumption of shape of the area under scrutiny - finds no curve over 10 miles ,  then there is none unless it is so small that it cannot be accounted for within instrument error .

Can I ask if this be brought back to the original and proper subject?, that is:

How, do you think, is the "round earth" conspiracy working? How is it kept a secret? How does the conspiracy hire new people? How many people 'know' the 'truth'? Why hasn't it leaked yet?'