Kent History Forum

History in Kent => General History => Topic started by: kyn on November 19, 2009, 17:24:03

Title: OS Trig Points and Bench Marks in Kent
Post by: kyn on November 19, 2009, 17:24:03
Thurnham
(http://i260.photobucket.com/albums/ii34/batgirlphotos/new/IMG_6015.jpg)

(http://i260.photobucket.com/albums/ii34/batgirlphotos/new/IMG_6012.jpg)

(http://i260.photobucket.com/albums/ii34/batgirlphotos/new/IMG_6014.jpg)
Title: Re: OS Trig Points and Bench Marks in Kent
Post by: Glen on November 19, 2009, 17:35:28
Hi Kyn - do you know if there is a list of trig points in Kent available somewhere on the net?

Glen
Title: Re: OS Trig Points and Bench Marks in Kent
Post by: seafordpete on November 19, 2009, 18:26:49
When the OS abandoned thm a few years back there was a group set up to "adopt" the trig points, seems it is still about as there are some in good nick. They may have a list otherwise it is work your way though the local OS map sets.
Title: Re: OS Trig Points and Bench Marks in Kent
Post by: kyn on November 19, 2009, 18:35:54
You could try doing a search here:  http://jeremyp.net/trigpoint/search.php

Or here:  http://www.trigpointinguk.com/
Title: Re: OS Trig Points and Bench Marks in Kent
Post by: Glen on November 19, 2009, 18:43:08
Thanks Kyn & Seafordpete

Glen
Title: Re: OS Trig Points and Bench Marks in Kent
Post by: Chatham_Girl85 on November 19, 2009, 18:43:54
can i ask what a trig is?
Title: Re: OS Trig Points and Bench Marks in Kent
Post by: Paul on November 19, 2009, 19:01:25
can i ask what a trig is?

Its a Triangulation point,For measuring distance. :)..........http://en.wikipedia.org/wiki/Triangulation_station
Its from Trigonometry...http://en.wikipedia.org/wiki/Trigonometry.
Title: Re: OS Trig Points and Bench Marks in Kent
Post by: unfairytale on December 01, 2009, 23:10:17
 This one in Adrian Street, Dover is shown as 77.68 on my old O.S. map (in feet).
(http://farm3.static.flickr.com/2621/4151578272_b90d14b319.jpg)
Title: Re: OS Trig Points and Bench Marks in Kent
Post by: unfairytale on December 23, 2009, 10:41:22
Crete Road East. Folkestone.
(http://farm3.static.flickr.com/2497/4207789933_856f600f89.jpg)
Title: Trig point
Post by: colin haggart on January 23, 2010, 22:43:35
I know that on here there is a place to put this, but I cannot find it, parhaps somewone can move this post to the right place please.

I saw on here one of these without any numbers, this one one I took a photo of is in Whitstable.
I did say in another post that they have numbers on them.


(http://i278.photobucket.com/albums/kk90/colinhaggart/GPO.jpg)
Title: Re: OS Trig Points and Bench Marks in Kent
Post by: unfairytale on January 24, 2010, 19:30:56
Dover seafront.
(http://farm3.static.flickr.com/2697/4300590499_c964aea8be.jpg)

(http://farm5.static.flickr.com/4056/4301341952_24304691f3_m.jpg) (http://farm5.static.flickr.com/4007/4301339740_c8fabe2f3e_m.jpg)
Title: Re: OS Trig Points and Bench Marks in Kent
Post by: DoverDan on April 13, 2010, 23:25:26
This one is next to the Farthingloe Heavy AA site Dover.
(http://farm3.static.flickr.com/2778/4519220438_25e5bfdfbc.jpg)
Title: Re: OS Trig Points and Bench Marks in Kent
Post by: seafordpete on April 14, 2010, 10:17:08
Never seen a cylindrical one before-any more about?
Title: Re: OS Trig Points and Bench Marks in Kent
Post by: DoverDan on April 14, 2010, 19:40:12
There are a couple of others that I know of, one is on top of Shakespeare Cliff (in the background of my photo). The other is on top of Cheriton Hill in Folkestone. I think these two were installed for the Channel Tunnel workings at Samphire Hoe and Cheriton, the Farthingloe one may have been for the A20 dual carriageway construction in the early 90s.
Title: Re: OS Trig Points and Bench Marks in Kent
Post by: merc on April 14, 2010, 21:16:19
There's a Trig Point in Fort Borstal: http://www.trigpointinguk.com/trigs/trig-details.php?t=3232
Title: Re: OS Trig Points and Bench Marks in Kent
Post by: DoverDan on April 25, 2010, 23:22:31
Walked past this bench mark so many times and only spotted it today. It is situated just west of Fan Hole coastal gun battery between Dover and St Margarets.
(http://farm3.static.flickr.com/2532/4552593162_9ed2fdc3b9.jpg)
Title: Re: OS Trig Points and Bench Marks in Kent
Post by: Jason on April 26, 2010, 21:22:36
can i ask what a trig is?

Its a Triangulation point,For measuring distance. :)..........http://en.wikipedia.org/wiki/Triangulation_station
Its from Trigonometry...http://en.wikipedia.org/wiki/Trigonometry.

I saw a programme on these once (and they say I don't know how to live! :) ) and it said that Brigadier Martin Hotine's work was so accurate that working through all the trig points from the west country to the north of Scotland, the total inaccuracy was less than 18 inches.  That's pretty good considering they were using manual instruments to measure all of the angles between the points.

They also had to carry the cement and moulds to cast the trig points up hills and mountains to wherever they were needed.

It seems it was a much tougher job than it seems at first :)

Mind you, we shouldn't be too surprised - Mason and Dixon (of Mason Dixon Line fame) were British, and they did a pretty good job of surveying that - maybe it's something in the water ;)

Jason
Title: Re: OS Trig Points and Bench Marks in Kent
Post by: DoverDan on May 20, 2010, 21:22:43
This trig point is on top of Shakespeare cliff near Dover overlooking Samphire hoe.
(http://farm4.static.flickr.com/3361/4624504083_f40d09e0b0_b.jpg)
Title: Re: OS Trig Points and Bench Marks in Kent
Post by: DoverDan on July 09, 2010, 22:46:34
I'm guessing this is a rather old trig point. It is located at East Demi Bastion east of Dover Castle close to the cliff edge.
(http://farm5.static.flickr.com/4118/4777540973_c2e58aab17_b.jpg)

(http://farm5.static.flickr.com/4080/4777561157_28da0f08c6_b.jpg)
Title: Re: OS Trig Points and Bench Marks in Kent
Post by: Glen on July 27, 2010, 23:26:56
Trig point at Rowdow Hill above Otford (204 metres)

(http://farm5.static.flickr.com/4104/4835285913_cb307bc7ae_b.jpg)

Glen
Title: Re: OS Trig Points and Bench Marks in Kent
Post by: DoverDan on August 07, 2010, 18:38:38
Trig point at Tolsford Hill near Folkestone.
(http://farm5.static.flickr.com/4137/4869397376_72b65299e6_b.jpg)
Title: Re: OS Trig Points and Bench Marks in Kent
Post by: unfairytale on August 07, 2010, 21:17:13
Im guessing this is a rather old trig point. It is located at East demi bastion east of Dover castle close to the cliff edge.

It is something to do with the Battery. A mount for a gun sight or something. There's one at Dover's shoulder of mutton battery:
(http://i303.photobucket.com/albums/nn151/unfairytale208/DSC07195.jpg)

 and one at the hospital battery at Dover castle:
(http://i303.photobucket.com/albums/nn151/unfairytale208/DSC07898.jpg)
Title: Re: OS Trig Points and Bench Marks in Kent
Post by: kyn on December 13, 2010, 11:27:50
Teynham Church
(http://i260.photobucket.com/albums/ii34/batgirlphotos/KHF/IMG_7519Small.jpg)
Title: Re: OS Trig Points and Bench Marks in Kent
Post by: Guest on December 13, 2010, 17:13:01
I wonder why we still call them 'trig' points, when officially they've been 'triangulation' points for decades? Even my old 7th Series 1" map shows them as such.
Title: Re: OS Trig Points and Bench Marks in Kent
Post by: Paul on December 13, 2010, 20:15:30
Trigonometry :)
Title: Re: OS Trig Points and Bench Marks in Kent
Post by: unfairytale on June 25, 2011, 23:24:03
On Martello Tower no.15. Hythe.
(http://farm4.static.flickr.com/3077/5870964586_51de5cc8e3.jpg)
Title: Re: OS Trig Points and Bench Marks in Kent
Post by: kyn on November 18, 2011, 13:03:53
St Margaret's Church, Horsmonden

(http://i260.photobucket.com/albums/ii34/batgirlphotos/KHF/IMG_1323.jpg)
Title: Re: OS Trig Points and Bench Marks in Kent
Post by: kyn on November 21, 2011, 22:02:58
St John the Baptist, Penshurst
(http://i260.photobucket.com/albums/ii34/batgirlphotos/KHF/IMG_1509.jpg)
Title: Re: OS Trig Points and Bench Marks in Kent
Post by: kyn on December 06, 2011, 18:11:46
St Peter and St Paul, Aylesford
(http://i260.photobucket.com/albums/ii34/batgirlphotos/KHF/IMG_1727.jpg)
Title: Re: OS Trig Points and Bench Marks in Kent
Post by: 101sean on December 06, 2011, 20:56:00
The Bench Marks are shown on 1:1250, 2500 and 10,000 OS plans along with their value, they were originally located roughly every 1/4mile in built up areas. The OS has a list of them but no longer maintains or install them, the coming of digital mapping, total stations and differential GPS has taken over. I used to use them a lot when surveying, it was frustrating to go on site and find the BM you were planning to use has been removed!

The bronze plate ones are fundamental BMs and are more widely spaced, they are designed to have a bracket inserted so you can rest the staff on it. On the incised ones, the staff holder uses something like a credit card to get the staff on the horizontal bar.

I can thoroughly recommend Map of a Nation by Rachel Hewitt if you want to learn more about the OS.
Title: Re: OS Trig Points and Bench Marks in Kent
Post by: BONZO on October 02, 2012, 14:11:16
Gosh - this brings back memories!

I used to be the Land Survey Technician for Polytechnic of the Southbank/Brixton School of Building.

Somewhere at the back of my shed with old surveying instruments I should have a Trivet plate for the top and a "L" shaped bracket for the Levelling staff.

Most of the student practicals were held down at Seaford, nothing in Kent I'm afraid.
Title: Re: OS Trig Points and Bench Marks in Kent
Post by: kyn on August 03, 2013, 19:53:20
Fort Borstal
Title: Re: OS Trig Points and Bench Marks in Kent
Post by: kyn on August 09, 2013, 14:38:53
St. John the Baptist, Barham.
Title: Re: OS Trig Points and Bench Marks in Kent
Post by: kyn on August 10, 2013, 22:28:57
St. Peter & St. Paul, Temple Ewell
Title: Re: OS Trig Points and Bench Marks in Kent
Post by: kyn on August 10, 2013, 23:52:15
St. Mary the Virgin, Lydden.

Title: Re: OS Trig Points and Bench Marks in Kent
Post by: kyn on August 22, 2013, 16:01:20
Two on the corner of the boundary wall surrounding Medway Hospital on Longhill Avenue and Windmill Road.
Title: Re: OS Trig Points and Bench Marks in Kent
Post by: merc on August 22, 2013, 16:20:13
Two on the corner of the boundary wall surrounding Medway Hospital on Longhill Avenue and Windmill Road.

I don't think I've ever noticed those two before :)
Title: Re: OS Trig Points and Bench Marks in Kent
Post by: kyn on August 22, 2013, 16:25:44
I hadn't although I look past there often.  I only saw them as I was convinced there has to be a boundary stone here somewhere and decided to have a closer look!
Title: Re: OS Trig Points and Bench Marks in Kent
Post by: kyn on August 27, 2013, 16:23:36
Possibly the original bench mark on the top of the guard house before the trig point was added at Fort Borstal.
Title: Re: OS Trig Points and Bench Marks in Kent
Post by: grandarog on August 27, 2013, 22:17:33
Bench mark on a Sarson Stone set in the wall corner of Twinney Lane, Upchurch.
Title: Re: OS Trig Points and Bench Marks in Kent
Post by: kyn on May 09, 2016, 18:42:46
All Saints, Staplehurst - or is it something else?
Title: Re: OS Trig Points and Bench Marks in Kent
Post by: kyn on May 09, 2016, 18:58:43
St. George, Benenden
Title: Re: OS Trig Points and Bench Marks in Kent
Post by: kyn on May 10, 2016, 20:16:13
Littlebourne Church
Title: Re: OS Trig Points and Bench Marks in Kent
Post by: 80sChild on May 11, 2016, 16:42:13
This is an interesting subject.  :)

I say that because last week they were talking about this on Radio 2, on the Jeremy Vine Show I think.
They explained all about Trig Points, their origins etc with an expert who phoned in.

They also said that a few years ago the government auctioned them all off, thus letting members of the public have a chance to 'adopt' one of them, and have a record of 'ownership'.

If I'm honest I've never heard of them before.

Also, looking through all the pictures and posts I've noticed that someone has posted a Trig Point literally just a stone's throw from where I live!  :)
Now that I know there's one in my vicinity I might go and look for it...
Title: Re: OS Trig Points and Bench Marks in Kent
Post by: kyn on May 11, 2016, 21:04:04
Such small things are often overlooked!  I think it is about time someone else added one, it seems to be only me at the moment :)
Title: Re: OS Trig Points and Bench Marks in Kent
Post by: kyn on May 31, 2016, 22:14:11
St. Mary's, Nackington
Title: Re: OS Trig Points and Bench Marks in Kent
Post by: kyn on July 17, 2016, 16:01:37
St. Peter and St. Paul, Eythorne
Title: Re: OS Trig Points and Bench Marks in Kent
Post by: CAT on December 09, 2016, 10:47:06
An elaborate bronze insert Bench Mark at St Leonard's Church, Upper Deal. The recesses would have been to attach a hanging bracket that would have enabled a piece of surveying equipment to be attached to aid in transferring the level to other locations.
Title: Re: OS Trig Points and Bench Marks in Kent
Post by: RonS on January 11, 2017, 12:20:33
http://www.bench-marks.org.uk/ provides a useful record of such things.

I have used this in reverse - using a GPS unit to discover the location of a lost building which, fortunately, once had a benchmark attached to it.