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[MH-list] Odd markings


bob clewley
 

Hi

I think you will find these are bench marks. If that is the case if you
look at an Ordinance survey map there will be a spot height associated
with it. It is a mark that was used to indicate how high above sea
level that particular place was.


bob

-----Original Message-----
From: Hilary [mailto:musicalj2@yahoo.co.uk]
Sent: 29 May 2003 15:13
To: motorhome-list@yahoogroups.com
Subject: [MH-list] Odd markings


Something the meaning of which eludes both me and a friend is an odd
sign which we have spotted on things as diverse as old buildings -
colleges, churches, and mileposts. It looks not unlike an inverted
War Department sign stamped on any piece of WD cutlery - that's going
back some, and the cutlery was purloined by my father when he was in
the RAF, so don't blame me!

It has a straight horizontal line, central to that is a line dropping
downwards at 90 degs, and either side of this central line are lines
at 45 degs. If you take the points of the compass, the main line
would read W to E, the central line (which meets but does not cross
it N) to the S, and the lines either side ESE and WSW (I think!).

They usually seem to be carved in stone, and we thought at first they
might be the mason's mark, but there is a diversity of age and
situation - some in Oxford, some in Huddersfield and Manchester. Any
light to shed on the subject?

Hilary


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Anthony Polson <acpolson@...>
 

Hilary wrote:

Something the meaning of which eludes both me and a friend is an odd
sign which we have spotted on things as diverse as old buildings -
colleges, churches, and mileposts. It looks not unlike an inverted
War Department sign stamped on any piece of WD cutlery - that's going
back some, and the cutlery was purloined by my father when he was in
the RAF, so don't blame me!

It has a straight horizontal line, central to that is a line dropping
downwards at 90 degs, and either side of this central line are lines
at 45 degs. If you take the points of the compass, the main line
would read W to E, the central line (which meets but does not cross
it N) to the S, and the lines either side ESE and WSW (I think!).

They usually seem to be carved in stone, and we thought at first they
might be the mason's mark, but there is a diversity of age and
situation - some in Oxford, some in Huddersfield and Manchester. Any
light to shed on the subject?


Hi Hilary,

They are Ordnance Survey "bench marks" which are precisely surveyed for their height above the zero level for the contours seen on ordnance survey maps. Their height is measured using precise methods and is accurate to about a cetimetre.

Like the "Trigonometrical Points" that you see on the tops of many hills, which are accurately surveyed in plan position (latitude and longitude, and/or grid reference), they are largely being supplanted by Global Positioning Systems (GPS) that use the same orbiting satellites as sat-nav systems in some expensive cars - and motorhomes!

Hope this helps!

Tony

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Jenny Wilson <j.wilson@...>
 

At 01:30 30/05/03 +0100, you wrote:
Hilary wrote:

Something the meaning of which eludes both me and a friend is an odd
sign which we have spotted on things as diverse as old buildings -
colleges, churches, and mileposts.
They are Ordnance Survey "bench marks" which are precisely surveyed for
their height above the zero level for the contours seen on ordnance survey
maps. Their height is measured using precise methods and is accurate to
about a cetimetre.

Like the "Trigonometrical Points" that you see on the tops of many hills,
which are accurately surveyed in plan position (latitude and longitude,
and/or grid reference), they are largely being supplanted by Global
Positioning Systems (GPS) that use the same orbiting satellites as sat-nav
systems in some expensive cars - and motorhomes!

Hope this helps!

Tony

I agree with this having lived in a 10 year old cottage 30 years ago. I
remember when the ordanance survey man came around looking for the bench
mark on the cottage. Every building marked on an ordanance survey map has a
benchmark on it somewhere. This shows it is marked on the map.

Jenny