Talk:Ordnance Survey National Grid/Archive 1

and O?
Does anyone else find it slightly odd that the southwest corner of the O square happens to sit exactly on the coast? Check out the map centred on OV000000 here and you'll see what I mean. Coincidence, or was the origin chosen to keep square O out of the picture? Presumably not, as the origin was set at 49&deg;N 2&deg;W, but it still seems strange.... — Preceding unsigned comment added by 143.252.80.124 (talk) 15:05, 10 June 2005 (UTC)‎
 * Adding to the strangeness, I beleive that two OS maps meet there two - there is no overlap at that point, and so there is a small square of North Yorkshire beach that is not on an OS-map or a recognised Grid Ref. What are they tring to hide?.......
 * Grinner 16:14, Jun 10, 2005 (UTC)

Copyright
Does Ordnance Survey hold the copyright on the British national grid reference system? Do I have to pay royalties if I include a grid reference in a publication? Edward 17:29, 2005 Mar 25 (UTC)
 * Do I have to pay royalties to a book publisher if I reference a particular page, line and word of one of their books? Laurel Bush 10:38, 1 Apr 2005 (UTC).
 * Yes, unfortunately, if it's Westlaw, as far as I understand it. They appear to claim that their numbering system for references is a creative work. See and . -- The Anome 08:39, May 18, 2005 (UTC)
 * Reading those references, I think this is a somewhat different case. Westlaw are (rightly or wrongly) arguing that the added value of their numbering system turns the, otherwise public domain, federal judicial decisions into a copyrightable derivative work. And therefore that other publishers cannot publish reports of judicial decisions based on their works. They don't appear to be arguing that others cannot cite references to their numbering system in other documents. -- Chris j wood 10:39, 18 May 2005 (UTC)


 * This is a popular myth, probably not helped by OS's aggressive protection of their IP more generally. Essentially the British National Grid is a particular specification of the Transverse Mercator projection, which was presented by Johann_Heinrich_Lambert some time in the in the 1770's and later updated by Gauß and Kruger in the C18th and early C20th respectively. As such any copyright on the projection is held with them an expired and has long expired (the degree to which each is a derivative work of the next is not in question here). The only original element in the BNG is the system of naming of grid squares. However, this was first set out by the OS in 1936, as stated in the article and is Crown copyright. Under the Copyrights Designs and Patents Act 1988, Crown copyright extends to 50 years from publication (unlike your or my work, which was extended to 70 years in the same Act) and so any claim OS may have had over this expired in 1986. — Preceding unsigned comment added by 128.240.229.7 (talk) 13:43, 18 November 2005‎ (UTC)
 * As far as I'm aware, current case law supports OS' ownership, given in Ordnance Survey vs Younger and others (Ch 10 April 1995), in which Sir Jeremy Vinelott, sitting as a Judge of the High Court, ruled that 'OS copyright material includes the National Grid' and that "the OS retain the right to refuse to allow...[someone]...to use the National Grid", a right which was in that case taken up. The Anome, you may be able to look this case up in Westlaw ;) -- Aled.greenhalgh 14:09, 31 March 2006 (UTC)

Sequence of presentation
Sequence of presentation: the article has a lot of good stuff in it, but to me at least (not an expert in datums and ellipsoids) the order doesn't seem right. The 'general' section discusses some very technical stuff about the coordinates and the underlying shape *before* the article has explained the system of grid letters and numbers. I'd think most readers would want to know how the system is used before reading about the technical details of the mapping. I won't edit the article because it's outside my area... Sangwine 20:28, 17 November 2006 (UTC)

1940s Introduction to the National Grid
I've got a 1940s OS map (updated popular edition of Inverness). On its cover, in two parts, is a nice introduction to the National Grid.

Since crown copyright only lasts 50 years, this introduction (and two diagrams) is now out of copyright. Does someone want to have a stab at integrating it into the page? A scan of the cover is at http://gagravarr.org/misc/NationalGridIntro.jpg and http://gagravarr.org/misc/NationalGridRefs.jpg. --Gagravarr 18:37, 4 December 2006 (UTC)
 * It's interesting to see that historically, national grid references were just numbers, of the form 51/176628 (which now resolves to TQ176628), could we add this somewhere as history? -- Grand Edgemaster Talk  16:03, 1 January 2007 (UTC)

Comment
Ditto on sequence: the article puts the cart before the horse. I'd rearrange it myself, but don't know enough about the topic, at least not yet.

Ludwig X 11:30, 7 October 2007 (UTC)

Two such Grid Systems...
The lede currently reads as: The British national grid reference system is a system of geographic grid references commonly used in Great Britain, different from using latitude and longitude.

The Ordnance Survey (OS) devised the national grid reference system, and it is heavily used in their survey data, and in maps (whether published by the Ordnance Survey or commercial map producers) based on those surveys. Grid references are also commonly quoted in other publications and data sources, such as guide books or government planning documents.

Two such systems exist for the United Kingdom: this article describes the one used for Great Britain and its outlying islands (including the Isle of Man); a similar system, used throughout Ireland (including Northern Ireland), is the Irish grid reference system (used jointly by the Ordnance Survey of Ireland and the former Ordnance Survey of Northern Ireland). Use of "United Kingdom" instead of "British Isles" is more accurate. If the point was really being made about the British Isles, then it's wrong since the Channel Islands have their own system. The point appears to be made because of an understandable potential confusion that all of the UK would use a single "British" system. The point being made here is that the UK uses two systems - one used on the island of Great Britain, and a different one used on the island of Ireland. I suggest that the lede would be clearer if it stated more clearly at the start that the UK uses two systems, and that this one is the system used on the island of Great Britain. Thoughts? --HighKing (talk) 10:12, 7 July 2010 (UTC)
 * What is the system used on the Channel Islands? -- Red rose64 (talk) 15:27, 7 July 2010 (UTC)
 * No idea. But they're not part of the British national grid reference system, or the Ireland system.  The Ordnance Syrvey website states  "The 326 primary control stations of the OSGB36 TRF cover the whole of Great Britain, including Orkney and Shetland but not the Scilly Isles, Rockall or the Channel Islands."  Another article on Geograph Britain and Ireland says "The Channel Islands fall outside Britain's grid system, but may be geographed using their local UTM grid."  This website also explains a little.  --HighKing (talk) 16:35, 7 July 2010 (UTC)
 * Strange that "The Channel Islands fall outside Britain's grid system", because the true origin of the British national grid lies to the SSE of Jersey, at 49°N 2°W. This would put the Channel Islands within national grid 100km square XD. -- Red rose64 (talk) 17:22, 7 July 2010 (UTC)

Copied from User_talk:David_Biddulph
Hi David - re: your revert on B.I / UK - that isn't the sense of the sentence. It currently (after your revert) reads "Two such systems exist for the United Kingdom: this article describes the one used for Great Britain and its outlying islands (including the Isle of Man); a similar system, used throughout Ireland (including Northern Ireland), is the Irish grid reference system (used jointly by the Ordnance Survey of Ireland and the former Ordnance Survey of Northern Ireland)." Doesn't that clearly say that there is one system for GB and outlying islands and other for Ireland? Therefore, surely there are two in the BI and not two in the UK? There may well be other UK systems, but that isn't how the sentence currently reads. Jamesinderbyshire (talk) 15:18, 8 July 2010 (UTC)
 * The point is that there is at least one other system in the British Isles (in the Channel Isles), but that is outside the UK. There are 2 systems in the UK, but at least 3 in the British Isles.  David Biddulph (talk) 16:13, 8 July 2010 (UTC)
 * Then the sentence is innacurate. At the moment it says there are two in the UK - one for GB and outlying islands - that by definition is the UK - and another for Ireland. That is not "two in the UK". It is two in the British Isles. Clearly it needs another modification to fit your information. Jamesinderbyshire (talk) 18:01, 8 July 2010 (UTC)
 * How exactly is the sentence inaccurate? You statement one for GB and outlying islands - that by definition is the UK is fantasy.  Since when does the "UK" not include Northern Ireland?  The article states there are two in the UK, and there are, and it does so for a reason.  The point being made in the article is that although there is a "British" grid system, not all "British" countries use the same system, since Northern Ireland uses a different one.  Your attempt to horseshoe "there are 3 systems in the British Isles" misses the point being made.  --HighKing (talk) 18:18, 8 July 2010 (UTC)
 * If you want to continue this discussion, the proper place is at the article Talk page. --HighKing (talk) 18:19, 8 July 2010 (UTC)
 * Now copied --HighKing (talk) 18:23, 8 July 2010 (UTC)
 * Let's try again. The sentence currently says:
 * Two different systems exist to provide grid references for the United Kingdom: this article describes the one used for Great Britain and its outlying islands (including the Isle of Man); 'a similar system, used throughout Ireland (including Northern Ireland), is the Irish grid reference system (used jointly by the Ordnance Survey of Ireland and the former Ordnance Survey of Northern Ireland).
 * Now it's clear that to any casual user (and not someone immersed in the particularities of what constitutes the exact UK territory) this implies there are two systems - one for the UK - and one for Ireland. If that's right, the original sentence before it was changed was quite correct and there are two for the British Isles. If that's not right - as David Biddulph has pointed out - then the sentence requires further modification. What it does not need is deletion of "British Isles" purely because the phrase itself is disliked for POV reasons, because there is no agreed policy on that point. Jamesinderbyshire (talk) 18:43, 8 July 2010 (UTC)
 * It states there are two different systems for the UK. One spans Great Britain.  A different one spans Northern Ireland.  The particularities of what constitutes the exact UK territory is what makes the sentence correct (and encyclopedic).  "Great Britain and its outlying islands" is not the UK.  A casual reader might assume that the British system covers the 4 constituent parts of "Britain" or the "UK".  The paragraph clarifies that contrary to reasonable assumptions, it doesn't.  And consider this your final warning on ad hominen attacks - this is the 5th time you've accused me of POV pushing and a campaign to remove "British Isles".  Next time, I'll report you.  As per WP:AGF, comment on the content, not on the contributor.  --HighKing (talk) 19:14, 8 July 2010 (UTC)
 * Here's the statement pre-HighKing: "Two such systems exist for the British Isles: this article describes the one used for Great Britain and its outlying islands (including the Isle of Man); a similar system, used throughout Ireland (including Northern Ireland), is the Irish grid reference system (used jointly by the Ordnance Survey of Ireland and the former Ordnance Survey of Northern Ireland).". The only question to be answered is - is this right or not? If it's not, then correct it, but there's no need to remove British Isles unless use of those words themselves are wrong. LevenBoy (talk) 19:34, 8 July 2010 (UTC)
 * Yes, at the moment the sentence refers to Ireland, so the use of British Isles was justified. If it's just about there being two - one for mainland UK and the other for Northern Ireland, which is the Irish system - then more precision is needed. Jamesinderbyshire (talk) 19:43, 8 July 2010 (UTC)
 * So would it make sense to revert to pre-HighKing then take if from there, without prejudice as to keeping or removing British Isles? LevenBoy (talk) 19:48, 8 July 2010 (UTC)
 * No. Because the statement is incorrect. There are three systems in the British Isles. The current version is accurate and correct.  --HighKing (talk) 19:49, 8 July 2010 (UTC)
 * Which are the three systems of the British Isles? Jamesinderbyshire (talk) 20:00, 8 July 2010 (UTC)
 * The 3 for the British Isles are one for GB, one for Ireland, and one for the Channel Isles. I said that earlier.  David Biddulph (talk) 21:26, 8 July 2010 (UTC)
 * I've corrected it properly now - in fact, this is a classic case for accurate use of the phrase "British Isles". There are not by the way three grid reference systems for the British Isles. Jamesinderbyshire (talk) 20:16, 8 July 2010 (UTC)
 * Sorry David, you are right and I hadn't quite twigged the Channel Islands bit - the current version is the correct one at last! Jamesinderbyshire (talk) 21:51, 8 July 2010 (UTC)
 * LevenBoy reverted against our consensus here. I've reverted back to what we've agreed.  --HighKing (talk) 11:32, 9 July 2010 (UTC)
 * I thought these were going to be discussed centrally HighKing. Are you already breaking that commitment? Why the rush to revert? Jamesinderbyshire (talk) 11:37, 9 July 2010 (UTC)
 * I'm putting it back. What consensus? There was none. The statement I'm reverting to is accurate. LevenBoy (talk) 11:43, 9 July 2010 (UTC)
 * I've just opened the discussion centrally on the SE page. I'm happy to honour the commitment so long as it's a commitment from both sides.  If (as has happened in the past) the commitment is ignored by editors who participate on the SE page but "reject" consensus there, and refuse to adhere to agreements there, then someone is taking the piss, and someone is being taken advantage of.  James, if you're serious about the SE page and doing this outside of LevenBoy's history of stonewalling and edit warring, I expect you feel the same way.  --HighKing (talk) 11:53, 9 July 2010 (UTC)
 * Yes, the last changes to this article took place before our agreement yesterday night to progress changes only on the SE page - then you reverted this today after we made that agreement. Hence my comment. Also LevenBoy it would be helpful presumably to avoid further edits here until it's been discussed centrally, to go with the flow. Jamesinderbyshire (talk) 12:18, 9 July 2010 (UTC)
 * I've just opened the discussion centrally on the SE page. I'm happy to honour the commitment so long as it's a commitment from both sides.  If (as has happened in the past) the commitment is ignored by editors who participate on the SE page but "reject" consensus there, and refuse to adhere to agreements there, then someone is taking the piss, and someone is being taken advantage of.  James, if you're serious about the SE page and doing this outside of LevenBoy's history of stonewalling and edit warring, I expect you feel the same way.  --HighKing (talk) 11:53, 9 July 2010 (UTC)
 * Yes, the last changes to this article took place before our agreement yesterday night to progress changes only on the SE page - then you reverted this today after we made that agreement. Hence my comment. Also LevenBoy it would be helpful presumably to avoid further edits here until it's been discussed centrally, to go with the flow. Jamesinderbyshire (talk) 12:18, 9 July 2010 (UTC)

What is "the SE page"? Neither SE nor WP:SE seem at all relevant. Wikilink please. -- Red rose64 (talk) 15:45, 9 July 2010 (UTC)
 * Hi Redrose64 - sorry, we should have been more explanatory - "SE page" refers to this discussion page, which explores the pros and cons of deleting or using the term "British Isles" - as this has been a long-running bone of contention, a special task force set of pages were established. The idea being to centrally discuss any examples there rather than (probably incorrectly) as has happened here in the article's talk page. Jamesinderbyshire (talk) 15:50, 9 July 2010 (UTC)
 * Oh cr*p. My watchlist just filled up. -- Red rose64 (talk) 16:34, 9 July 2010 (UTC)
 * LOL. I didn't know that could happen, but I do now. I was thinking of publishing a brief 600-page synopsis of the Debate So Far to assist people, who, like myself, have only had a few months to familiarise themselves with the scale of it. Jamesinderbyshire (talk) 17:01, 9 July 2010 (UTC)
 * I'm sure you could get it down to 500 pages. No point in overkill is there?  --HighKing (talk) 16:12, 10 July 2010 (UTC)
 * There's enough there to start a seperate wiki devoted to the subject. I assume you would be Arch-Sysop HighKing and Lord Pursuivant Pursuer of Expungence of the Dread "BI" Phrase? Jamesinderbyshire (talk) 16:14, 10 July 2010 (UTC)
 * I don't think people "get" the idea that I'm not trying to expunge the term. Nor is it "dreaded".  But there is definitely a "gap" between the mentality of some editors.  Without being too generalist I hope, some editors (maybe most happen to be English or British) don't understand why it's not correct (or acceptable, or even offensive to some people) to use the term as a lazy shorthand for "UK" or "GB & I".  Anyway, probably not appropriate for discussion on this page - we should perhaps discuss at the WT:BISE page.  --HighKing (talk) 16:27, 10 July 2010 (UTC)
 * Some of "us" (dread Anglos) do perhaps partly get it HK - at least to the point of realising it causes offence to a segment of opinion. As always, the issue is about deciding how much "offense" should be a basis for action in Wikipedia. There must be lots of times when just because people are offended by some entry or article, does not mean it should be deleted. Of course, this is always harder to see when you're the one who is offended, either personally or politically. A big problem is that the uninvolved editors from other regions of the world or cultures do not on the whole involve themselves - so disputes like this are left to those closest to resolve. Both in and out of make-believe wiki-land. Anyway, relax, I was just joking. Jamesinderbyshire (talk) 16:57, 10 July 2010 (UTC)
 * No probs. I'll admit I'm a tad sensitive to being labelled anti-British to be point of being illogical and maniac, and attempting to delete British Isles from everywhere I see it.  Mostly because my socky followers behaved as they did, and a lot of editors repeated comments without fairly looking at my actions and behaviour.  I'm not counting you in that now, but the first couple of our encounters looked like it was about to happen again.  Anyway, this Talk page isn't really the place... --HighKing (talk) 17:39, 10 July 2010 (UTC)

Topic title change?
I do not know how to do this but should the title of this topic be ... The National Grid.

That is what it is officially called.

It seems the title is a mix up and should at least be capitalised.

And there does not seem to be a lot of history included ... e.g. no mention of British Grid System etc.

Regards. --Triton Rocker (talk) 04:57, 11 July 2010 (UTC)
 * It already has to be disambiguated at National Grid, so presumably that's an issue. I always heard it called the "OS grid" at school. "British national grid" appears to be a Wikipedianism because of disamb problems. Jamesinderbyshire (talk) 09:39, 11 July 2010 (UTC)

The Ordance Survey use comes first. Certainly historically. And it is still a proper name so shouldn't it be capitalisation? --Triton Rocker (talk) 01:48, 12 July 2010 (UTC)
 * The OS call it the "National Grid", so that's where the problem arises. It could and probably should in Wikipedia be called the Ordnance Survey National Grid and that would take it off the disamb page problems. Jamesinderbyshire (talk) 10:09, 12 July 2010 (UTC)
 * Sounds good to me. --HighKing (talk) 10:19, 12 July 2010 (UTC)
 * Better than it is now. The Irish grid reference system should be The Irish Grid or capitalised. --Triton Rocker (talk) 16:38, 12 July 2010 (UTC)
 * The term "Irish Grid Reference System" is at least verifiable. -- Red rose64 (talk) 16:44, 12 July 2010 (UTC)
 * Those tables on that page seem to suggest the official name is "Irish Grid" - then again, the page is headed Irish Grid Reference System. Perhaps "Reference System" is just standard nomenclature in the business for the type of thing it is, not the name of the thing. Just a thought. Jamesinderbyshire (talk) 18:35, 12 July 2010 (UTC)
 * Do we have a consensus to move this article to Ordnance Survey National Grid now? Any objections? Thanks. Jamesinderbyshire (talk) 19:56, 14 August 2010 (UTC)

Move completed as per discussion above. Jamesinderbyshire (talk) 20:54, 17 August 2010 (UTC)

Redfearn series
I just tried to follow some links around and I notice that this has a section on the ordinance survey (labeled OSGB which redirects here) Transverse_Mercator:_Redfearn_series

There seems to be no mention of the redfearn series on this page. EdwardLane (talk) 10:14, 28 February 2012 (UTC)

Six-figure references
Some sources which could be included in the future (I intend to do so myself at some point, but can't now): -- Trevj (talk) 13:24, 19 April 2013 (UTC)
 * http://www.le.ac.uk/ar/arcgis/OS_coords.html
 * http://www.magazine.ordnancesurveyleisure.co.uk/magazine/tscontent/editorials/outdoor-skills/2012/os-grid-references.html

I* is cross-reference to the Irish grid
Some databases, at the very least http://www.ofcom.org.uk/radio/ifi/rl/commer/ar/tech_parameters/?a=87101, turn an Irish national grid reference system square into a general square by preceeding the Irish square with I (note that irish references have only one letter at the beginning, so this works out to the same format).

I have also seen references that claim to lay in square CI and being somewhere in the channel islands, but all my searches simply say that there is no national grid covering the channel islands.

At least the I* bit should probably be worked into the main text, but I don't know quite where to do so. — Preceding unsigned comment added by Theorbtwo (talk • contribs) 20:13, 17 September 2005‎ (UTC)


 * Re: The I for the Irish Grid - DMA 8538.1, Par. 2-1.5.1 says to use I as the grid letter with the Irish Transvers Mercator Grid, as an exception to the Normal British Grid Reference System method of lettering. — Preceding unsigned comment added by 205.175.225.5 (talk) 22:21, 9 February 2006‎ (UTC)
 * The CI's use the international UTM grid afaik. — Preceding unsigned comment added by 82.153.105.50 (talk) 19:24, 9 June 2013 (UTC)

Clean-up is needed
Both the article and its Talk do need re-arranging.

Examples in Talk are its first word "Ditto" suggesting a misplaced comment on another point and the Unref template possibly meant for the article itself.

The article early mentions the Airey spheroid (by the way shouldn't that be included in the list of parameters?) which must leave the non-technical reader way up in the air wondering how esoteric can you get in a supposedly encyclopedic article.--SilasW (talk) 12:05, 5 March 2008 (UTC)
 * I've sorted out the talk page as best I can, by extracting random mid-thread and top-of-page comments to new threads, placing those into what I believe to be the proper chronological order; I've also added or  to all unsigned posts. -- Red rose64 (talk) 23:39, 9 June 2013 (UTC)

All-numeric grid references ambiguous?
How is an all-numeric grid reference for the far north distinguishable from a one digit more precise grid reference in the south west? — Preceding unsigned comment added by 88.96.79.118 (talk) 20:49, 25 February 2014 (UTC)
 * The two components of a grid reference - the eastings and the northings - are always given to the same precision. Therefore, if the gridref is for a point less than 1000 km north of the false origin, the northings will have the same number of digits as the eastings (all points in Great Britain are less than 1000 km east of the false origin); and so the total number of digits will be even. If the gridref is for a point 1000 km or more north of the false origin, the northings will have one more digit than the eastings; and so the total number of digits will be odd. This even=south/odd=north rule holds for all levels of precision. If you like, you can take a gridref with an odd number of digits and put a zero at the start. It will then split exactly into two halves - one for the eastings and one for the northings. -- Red rose64 (talk) 10:05, 26 February 2014 (UTC)
 * The example given has an even number of digits, but is north of the line. Ought the example to be changed to remove the leading zero from the eastings?  Is there a RS for how many figures should be shown? --David Biddulph (talk) 10:58, 26 February 2014 (UTC)
 * Assuming that you mean the grid reference for Sullom Voe oil terminal - - a simple context check reveals whether it's north of the line or not. This gridref, if read correctly, is for a point 439.6 km east, 1175.3 km north of the false origin; now assume that we have read it as being one-tenth of that, i.e. 43.96 km east, 117.53 km north. That would place it in the blank square to the west of square SR - I don't believe that there are any islands in this part of the Atlantic Ocean. -- Red rose64 (talk) 12:36, 26 February 2014 (UTC)
 * So I think that you are now saying that the answer to the OP is that the way of resolving the ambiguity is to see whether the eastings are on the wet bit or the dry bit, rather than necessarily being able to resolve it by the number of digits? I think you are correct. --David Biddulph (talk) 13:06, 26 February 2014 (UTC)
 * Or to expand that, I think that half of your original answer was correct, in that an odd number of digits would be to the North. If the number of digits is even we have to resort to the wet/ dry test. --David Biddulph (talk) 13:09, 26 February 2014 (UTC)
 * The OP didn't actually direct me to any examples, so I kind-of made assumptions. But the problem of ambiguity only arises when the northings begins with a 1 - this could mean either the three rows where the letters are between HP and HZ - or the row which includes squares SR to TR inclusive. If it's the former, the eastings can only begin with a zero; and if the latter, the eastings can begin with any digit from 1 to 6 inclusive - but not zero. -- Red rose64 (talk) 13:16, 26 February 2014 (UTC)

Is there any OS-specified standard for all-numeric grid references? It seems surprising that heuristics of the kind described above would be required to process a reference. Certainly not all the converters on the web follow these heuristics; rather they seem to expect that all-numeric references will be at 1m resolution (e.g. http://www.nearby.org.uk/conversions-more.cgi). — Preceding unsigned comment added by 88.96.79.118 (talk) 14:02, 26 February 2014 (UTC)

Conversion from OS letters and 6-digits to all digits
eg NN 136888 NN is at 200km,700km adding the offsets, "2"+"136"+"00" and "7"+"888"+"00" gives Easting (m) = 213600, Northing (m) = 788800. QuentinUK (talk) 11:29, 18 February 2015 (UTC)
 * Yes; is there a problem in the article? -- Red rose64 (talk) 16:19, 18 February 2015 (UTC)

External links modified
Hello fellow Wikipedians,

I have just added archive links to 1 one external link on Ordnance Survey National Grid. Please take a moment to review my edit. If necessary, add after the link to keep me from modifying it. Alternatively, you can add to keep me off the page altogether. I made the following changes:
 * Added archive https://web.archive.org/20100605002533/http://www.wherearewe.co.nz/index.php/calculators/geodetics.html to http://www.wherearewe.co.nz/index.php/calculators/geodetics.html

When you have finished reviewing my changes, please set the checked parameter below to true to let others know.

Cheers. —cyberbot II  Talk to my owner :Online 14:04, 18 October 2015 (UTC)

Introduction & General
The above-named sections do not, to my mind, give a clear idea of the exact positioning of the National Grid with respect to the Lat/Long system. It subsequently appears that, by definition : (a) the point 49°N, 2°W (in the English Channel) has the Grid position 400.000 km east, -100.000 km north ; (b) at that position the 400 km east Grid line has the same direction as the 2°W line of longitude - all else being deduction and geodesy. Its six-figure Grid Reference would be XZ000000, if the lettering of large squares were extended southward from S# & T# in the corresponding manner as northward.

I suggest that something like that, corrected if/as necessary, should be put quite near to the beginning of the Article. 94.30.84.71 (talk) 11:23, 28 May 2017 (UTC)
 * I believe that some years ago I added the information about the true origin being 49°N 2°W. However, this point would actually have the six-figure grid ref XE000000 (XZ000000 would be 400 km further south along the same meridian), but we can't mention that without an explicit source, per WP:NOR and WP:V. -- Red rose64 &#x1f339; (talk) 19:41, 28 May 2017 (UTC)

Military origins of largest grid squares...
RE the apparent military origins of the Ordnance Survey National Grid - I found an older, "official" source as now in the article, at http://web.archive.org/web/20060517190658/http://www.ordnancesurvey.co.uk/oswebsite/gps/information/coordinatesystemsinfo/guidetonationalgrid/page9.html, though nothing current (previously my statement followed one at https://www.geograph.org.uk/article/In-Search-of-OV0000, that was not sourced further). However attempts to find anything more illuminating have been unsuccessful to date, leaving a bit of a mystery - although clearly the O.S. did adopt parts pf a pre-existing grid, otherwise the square notation makes no sense. Wondering if anyone else knows the original story, and whose/which grid was adopted - seems like a fundamental part of the picture to me. Cheers Tony 1212 (talk) 19:04, 11 December 2020 (UTC)
 * I had a quick look for evidence and only found Penny (2000) which discusses the differences from a practical point of view but I haven't searched any further.--Northernhenge (talk) 23:41, 11 December 2020 (UTC)