Heavens' Henge

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Re: Heavens' Henge

Postby Boreades » 2:30 pm

jon wrote:Aha.. afraid it does: The only time that sunset and sunrise are in opposing directions is at equinox:


My mistake for not making it clearer; I wasn't assuming opposing directions on an equinox, quite the opposite. I'm assuming the sunrises and sunsets would be measured at different times of the year, as they rotate around the compass with the seasons.

Hence the need for patience!
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Re: Heavens' Henge

Postby Boreades » 8:53 am

The other flaw in my idea is the assumption that the horizon is flat and level. Fine if you are looking out to sea, but not if you are looking down into the Vale of Pewsey.
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Re: Heavens' Henge

Postby Mick Harper » 4:01 pm

I'll copy this AEL post here because it seems majorly relevant to these proceedings.

I have just finished a very odd book called The Trojan War of 650 BC by Alan Wilson and Baram Blackett. More perhaps on this later but one thing that did come out of it was the following:
1. Apparently Google Earth allows you to find the height above sea level of anywhere in the world.
2. But when you target a manmade structure, eg the Empire State Building, it gives you the height-above-sea-level of the ground on which the building stands, not the top of the building.
3. So far not surprising.
4. But when you target something which is manmade but not a building eg Silbury Hill, the figure that comes out is the natural substrate not the top of the actual 'hill'.
5. So if we didn't know it before we'd know, thanks to Google Earth, that Silbury Hill is man-made.
6. So can someone who knows how to operate Google Earth please start re-examining everything we are interested in, possibly starting with Glastonbury Tor.
7. You can have the weekend off.
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Re: Heavens' Henge

Postby Boreades » 10:58 pm

Are we supposed to believe that Google Earth is now a sentient being that can decide whether anything is man-made or not?
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Re: Heavens' Henge

Postby Mick Harper » 10:59 pm

I do not understand. Please clarify.
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Re: Heavens' Henge

Postby Boreades » 11:12 pm

1) Google Earth, in all it's glory, is just a portal for geographic data, however very well it is presented.
2) That data is entered into the GE system by humans who make arbitrary and partial decisions, based on goodness knows what.

Open the pod bay doors HAL?
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Re: Heavens' Henge

Postby Mick Harper » 11:27 pm

All right, let us take it step by step.

1) When reporting the height of 'land' upon which the Empire State building sits, what in your opinion is the number produced by the Google Earth satellite -- is it a) the top of the mast on top of the building b) the top floor of the building c) the ceiling and/or other infrastructure sitting above the top floor d) the height of the land upon which the building stands or e) some other figure?
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Re: Heavens' Henge

Postby TisILeclerc » 6:53 am

When I worked for the GC section at the Ordnance Survey we used lengths of string, sticks and other bits and bobs to get the height above sea level.

These days they apparently use flying machines.

'So that’s the answer right? Well not quite. Satellite technology has transformed map making, however because of the time it takes to get an accurate height, it remains impractical to measure every mountain in this way. That’s why we use an alternative method for measuring most of Britain’s hills and peaks.

It's called photogrammetry, something we’ve covered before on the blog. It involves flying the area to be measured taking overlapping, high resolution photos from which a 3D representation is then created. Measurements can then be taken that translate directly to positions and heights in the real world.'

http://www.ordnancesurvey.co.uk/blog/20 ... -mountain/

The link to 'photogrammetry' doesn't work but I'm sure it can be found somewhere. I don't know whether Google uses similar techniques or perhaps they just drive their little cars up to the top and check the altimeter.

There's an interesting site, for some, that gives a simplified method of using OS data for studying 'landscape geometry'. They specifically mention Glastonbury Tor. And also Ben Nevis. Perhaps there's a connection. It doesn't make sense to me but then they go above ten so that rules me out.

http://www.cantab.net/users/michael.beh ... /main.html

The Daily Mail as always has its finger on the pulse of all things hill shaped and after much research confirms that Silbury Hill is man made. Although they can't rule out the accidental element. It may have been made by accident over hundreds of years.

Image


In the comments section at the bottom John Robert Langdon has something to say. Isn't he the bloke who wrote a book claiming the whole area was flooded and all these places were built on islands?

'Robert John Langdon, Ongar, Essex, 4 years ago

Its the largest man-made object from prehistory and took 18 million man hours to build.... Its certainly no accident!! If you look back to when it was built the landscape was very different from today, lot more trees blocking the view and it was surrounded by water. The problem current archaeologist have is that they look at the 'now not the then' aspect of the environment, if you did the simple solution will be obvious.... it's a man-made island, that in Neolithic times would be surrounded by water as the avon was 20m higher than today.'

http://www.dailymail.co.uk/sciencetech/ ... ident.html
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Re: Heavens' Henge

Postby Mick Harper » 11:25 am

It involves flying the area to be measured taking overlapping, high resolution photos from which a 3D representation is then created. Measurements can then be taken that translate directly to positions and heights in the real world.'

This is the critical question. Such a method is fine as a way of providing maps where a) not all places need to be exactly recorded for height and b) where manpower is not an issue. In other words it is fine for the OS who are producing physical maps where the viewer is constantly estimating heights for himself by examining contours and suchlike; and each physical map lasts ten years, is widely purchased and therefore can afford a team of mapmakers to produce it.

As I understand it (which is not very far), Google Maps are quite different. First, every point you click on has a unique height and second, there are just three men and a dog in Silicon Valley responsible for the whole world. In other words, Google must have a system of automatism. The altimeter/camera/radar is recording the height directly. It is this that gives us our opportunity since there is the possibility that it is 'natural ground level' that is being 'pinged' and everything non-natural built upon it is being ignored.

OS mapmakers would put a spot height on Silbury Hill because they are not concerned with whether it is manmade or not. The users of the map would regard it as a hill whether it was or not. But presumably they would ignore the Empire State Building for height purposes (it would make for some very tight contour lines!) and record the ground on which it is built.
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Re: Heavens' Henge

Postby Boreades » 9:34 pm

TisILeclerc wrote:The Daily Mail as always has its finger on the pulse of all things hill shaped and after much research confirms that Silbury Hill is man made. Although they can't rule out the accidental element. It may have been made by accident over hundreds of years.


This is the kind of "accident" you get when folk are iteratively refining their geometry. A kind of "are we there yet?" approach. Perhaps as they gradually improved the precision of their measurements?

Dr Jim Leary & Co are guilty of some basic assumptions e.g. all the material was available for a continuous build. But let's not forget that building Silbury would, for pragmatic civil engineering reasons, have been a seasonal effort, when labour was most available and the weather was most suitable for large-scale earth moving.

We (and the ortho-archeos) need a civil engineer's insight, on what construction techniques would be the most efficient.
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