inquisitive

• 1093
Re: Why are all FE models discs?
« Reply #20 on: January 01, 2023, 11:02:33 PM »
The WGS83 model gives all the details you need.  Also the angles of dishes for broadcast satellites.

WGS83 takes data from small flat maps: https://wiki.tfes.org/World_Geodetic_System_1984

I haven't seen a study of triangulation of satellites to prove that we live on a globe. This is an assumption that such studies exist.

Your position is flawed. Unless they did something like walking around with a digital measuring wheel and physically measured the earth with a tactile method, there were assumptions in measuring long distances.

Actually, they generally used chains back in the day.
surveyor’s chain, also called Gunter’s chain, measuring device and arbitrary measurement unit still widely used for surveying in English-speaking countries. Invented by the English mathematician Edmund Gunter in the early 17th century, Gunter’s chain is exactly 22 yards (about 20 m) long and divided into 100 links. In the device, each link is a solid bar. Measurement of the public land systems of the United States and Canada is based on Gunter’s chain. An area of 10 square chains is equal to one acre.

This is equivalent to saying that surveyors had rulers. Maybe they did have rulers. But it doesn't prove that they measured long distances with them.

If they used a digital measuring wheel then that would also mean making an assumption - that the wheel is calibrated correctly and accurate.

Your objection to “assumptions” is very selective. The Bishop Experiment makes assumptions, Rowbotham made assumptions. You have no issues with that. Only when an experiment or technique yields results you don’t like do you switch to the skeptical context and start objecting to “assumptions”.

You have previously agreed that GPS can accurately give your longitude and latitude. How can it do that without distances being known? Leaving aside how that would work in the middle of an ocean, as it demonstrably does, which rules out any land based solution

There are ways to test whether a digital measuring wheel is calibrated and accurate. This would be more of an experiment where the conditions can be controlled.

Other methods are not as controlled, and assume a lot about astronomy or the weather.

Latitude and Longitude are references ultimately based on astronomical phenomena. The Latitude is based on the angle of the North Star in the sky (for the NH) and Longitude is related to clocks and time zones. You might know your Lat/Lon coordinate point, but this would do nothing to show the distance between those points. This is how GPS, and formally the land-based LORAN, operate. The station knows its own coordinates and it is giving you your own coordinates based on triangulation.

Much of professional GPS and GIS work, by the way, assumes that the earth is flat.

From https://www.e-education.psu.edu/geog862/book/export/html/1644

“ Welcome to Lesson Six of this GPS course. And this time, we'll be talking about two coordinate systems. And I have a little bit of discussion concerning heights. We've touched on that a little bit. Now these coordinate systems that we're going to discuss are plane coordinate systems based upon the fiction that the earth is flat, which, of course, immediately introduces distortion. However, much of GIS work—and GPS work as well—is done based upon this presumption. ”

The fact that the calculations to align a satellite dish actually work and are based on a round earth should satisfy you. The locations of geostationary satellites are well documentated.  Dishes near the equator point up around 90⁰. Those north and south at a lower angle.

andiwd

• 14
Re: Why are all FE models discs?
« Reply #21 on: January 02, 2023, 09:04:12 AM »
This is equivalent to saying that surveyors had rulers. Maybe they did have rulers. But it doesn't prove that they measured long distances with them.
What do you consider "long distances" and how else would you suggest measuring them with 17th century technology?

By long distances I mean continental or inter-continental distances. Much of surveyor work was plotting small parcels of land or water, and didn't really seek to measure the earth. They had tools to do the job of direct small-scale measurements, but they weren't measuring long distances with ruler tape.

For long distance measurements in the 17th century and prior the first step was to get your longitude and latitude. From that you could know how far away another place with a known latitude and longitude was if you knew how many miles a degree took upon the earth. It was "known" how many miles a degree took upon the earth based on a study, to which they would take and apply to Lat/Lon coordinates on a theoretical basis. They were not stringing ruler tape or chains for all long distance work. Long distance 'measurement' worked, and still works, based on a series of assumptions.

What about undersea cables. Surely the southern cross NEXT cable from Sydney to Los Angeles (via a few South Pacific Islands) at 15,840km is a valuable tool to eliminate several maps on the wiki. Yes you can argue that the exact mathematically shortest distance may be different to the cable length but it still provides a maximum distance.

As you can see by the following link there are many other cables under the Pacific Ocean which would invalidate the most often shown monopole maps on the wiki

https://www.submarinecablemap.com/submarine-cable/southern-cross-next

Source

https://www.telstra.co.uk/en/news-research/articles/southern-cross-next--sx-next--connecting-los-angeles-and--sydney

Longtitube

• 228
Re: Why are all FE models discs?
« Reply #22 on: January 02, 2023, 05:01:02 PM »
For long distance measurements in the 17th century and prior the first step was to get your longitude and latitude. From that you could know how far away another place with a known latitude and longitude was if you knew how many miles a degree took upon the earth. It was "known" how many miles a degree took upon the earth based on a study, to which they would take and apply to Lat/Lon coordinates on a theoretical basis. They were not stringing ruler tape or chains for all long distance work. Long distance 'measurement' worked, and still works, based on a series of assumptions.

How very interesting, how was this number of miles per degree "known"?

To answer that, here's a link to a 17th century work on the same subject. The author sought to verify the "known" number of miles per degree by actually measuring, by surveyor's chain, the distance from London to York and comparing the difference in latitude and longitude with this directly measured distance. In the course of the book, he also mentions how others through history had physically measured distances to determine, say, latitude difference compared to distance in cubits or stadia etc.

The Seaman's Practice by Richard Norwood:– https://ia803203.us.archive.org/16/items/norwood-1699-the-sea-man-s-practice/Norwood%201699%20The_Sea_man_s_Practice.pdf

You'll find he uses 17th century English spelling – it'ʃ difficult to ʃay at timeʃ how theʃe thingʃ might be pronounced without aʃsiʃtance...
Once again - you assume that the centre of the video is the centre of the camera's frame. We know that this isn't the case.

stack

• 3583
Re: Why are all FE models discs?
« Reply #23 on: January 02, 2023, 05:06:54 PM »
This is equivalent to saying that surveyors had rulers. Maybe they did have rulers. But it doesn't prove that they measured long distances with them.
What do you consider "long distances" and how else would you suggest measuring them with 17th century technology?

By long distances I mean continental or inter-continental distances. Much of surveyor work was plotting small parcels of land or water, and didn't really seek to measure the earth. They had tools to do the job of direct small-scale measurements, but they weren't measuring long distances with ruler tape.

For long distance measurements in the 17th century and prior the first step was to get your longitude and latitude. From that you could know how far away another place with a known latitude and longitude was if you knew how many miles a degree took upon the earth. It was "known" how many miles a degree took upon the earth based on a study, to which they would take and apply to Lat/Lon coordinates on a theoretical basis. They were not stringing ruler tape or chains for all long distance work. Long distance 'measurement' worked, and still works, based on a series of assumptions.

What about undersea cables. Surely the southern cross NEXT cable from Sydney to Los Angeles (via a few South Pacific Islands) at 15,840km is a valuable tool to eliminate several maps on the wiki. Yes you can argue that the exact mathematically shortest distance may be different to the cable length but it still provides a maximum distance.

As you can see by the following link there are many other cables under the Pacific Ocean which would invalidate the most often shown monopole maps on the wiki

https://www.submarinecablemap.com/submarine-cable/southern-cross-next

Source

https://www.telstra.co.uk/en/news-research/articles/southern-cross-next--sx-next--connecting-los-angeles-and--sydney

Seems pretty close considering the less than straight route and offshoots to New Zealand and such...

AATW

• 6549
Re: Why are all FE models discs?
« Reply #24 on: January 02, 2023, 10:53:29 PM »
Latitude and Longitude are references ultimately based on astronomical phenomena. The Latitude is based on the angle of the North Star in the sky (for the NH) and Longitude is related to clocks and time zones. You might know your Lat/Lon coordinate point, but this would do nothing to show the distance between those points. This is how GPS, and formally the land-based LORAN, operate. The station knows its own coordinates and it is giving you your own coordinates based on triangulation.
Incorrect, as you are wont to say.
GPS uses trilateration, not triangulation.

https://gisgeography.com/trilateration-triangulation-gps/

You have agreed GPS can tell you your longitude and latitude. But mapping applications can use that information to accurately plot routes between one set of co-ordinates and another. How can it do that if it doesn't know the distance between them? And while we are here, the distance between degrees of Longitude is highest at the equator and gets smaller the further north or south you go. But on the monopole FE map the distance would have to keep getting bigger and bigger the further south you are. Some simple testing in Australia would immediately show that to be incorrect.

Quote
Much of professional GPS and GIS work, by the way, assumes that the earth is flat.
So? This is like your somewhat dishonest quoting elsewhere in the Wiki of some aerodynamics manual which talks about a flat earth. But it does so listing it as a simplification. It also lists as another simplification the airplane being of constant mass - which it won't be of course as it is constantly using fuel. So yes, sometimes simplifications are used but the very fact they're acknowledged as simplifications shows that they do not match the reality. In fact, the part you quoted
says: "the fiction that the earth is flat, which, of course, immediately introduces distortion"
And the very next sentence, which you didn't quote, says "it is worthwhile to spend some time discussing how the distortions are handled". A paragraph or two later it says:

Quote
As long as the extent of the coverage of the coordinate system is limited, the curvature aspect—while it leads to distortion—can be managed. It's when the flat map, the flat coordinate system, extends beyond a limited area that the distortion can get out of hand.  Therefore, the projection of points from the Earth’s surface onto a reference ellipsoid and finally onto flat maps is still viable.

And on map projections it says:

Quote
State Plane Coordinate Systems are built on map projections. Map projection means representing a portion of the actual Earth on a plane. Done for hundreds of years to create paper maps, it continues, but map projection today is most often really a mathematical procedure done in a computer. Nevertheless, even in an electronic world, it cannot be done without distortion.

In fact much of the article you posted is discussing the problem of projection from the surface of an ellipsoid earth on to a plane. Why is any of that necessary? If the earth is flat then no projection is required. But in reality it is. Why?
Tom: "Claiming incredulity is a pretty bad argument. Calling it "insane" or "ridiculous" is not a good argument at all."

TFES Wiki Occam's Razor page, by Tom: "What's the simplest explanation; that NASA has successfully designed and invented never before seen rocket technologies from scratch which can accelerate 100 tons of matter to an escape velocity of 7 miles per second"

Longtitube

• 228
Re: Why are all FE models discs?
« Reply #25 on: January 03, 2023, 08:30:28 PM »
Latitude and Longitude are references ultimately based on astronomical phenomena. The Latitude is based on the angle of the North Star in the sky (for the NH) and Longitude is related to clocks and time zones. You might know your Lat/Lon coordinate point, but this would do nothing to show the distance between those points. This is how GPS, and formally the land-based LORAN, operate. The station knows its own coordinates and it is giving you your own coordinates based on triangulation.

AATW has already dealt with GPS and trilateration, but you're also incorrect that LORAN used triangulation. It used multilateration to fix a position, as did its shorter-range cousin the Decca Navigator system.

https://en.wikipedia.org/wiki/Loran-C

Once again - you assume that the centre of the video is the centre of the camera's frame. We know that this isn't the case.