GPS to grid reference

Roger said:

The secret is what they actually mean by Grid Reference. A secret you
apparently weren't in on and now suggest doesn't matter.

If I'm not in on it, then the fact that I can use maps and grids anyway
is yet another demonstration it's a non-issue.

Quoted message said:

There are 2 issues at stake. The first is the commonsense one that you
don't expect to be deliberately misinformed by purveyors of facts. The
second is that when you are aiming at something approximate you are
better off if your target is at the middle of the expected range, not
the extreme end.

But if you're at a suitable degree of accuracy then it's more or less on
it anyway.

If you want to convince me (or anyone else) this is a genuine problem it
would help if you could highlight, preferably with real map example(s),
how a feature will easily get lost or the wrong one picked up because of
using one assumption rather than the other. I don't think it's a
problem because I've never come across such a thing happening, and that
you've never yet highlighted problems beyond abstract theoretical ones
suggests to me that you haven't either. Otherwise you can go through
life worrying about it and I'll just do my navigation without Big
Secrets, but knowing where I am and finding where I'm going anyway...

Pete.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net [email hidden] http://www.dundee.ac.uk/~pjclinch/

Bernard Hill said:

I'll look out for that. But I was hoping to get under £50 since the
electronics obviously comes that sort of price.

eBay is probably your friend here.

From a quick trawl it's possible to get a basic unit (say, an eTrex or
Explorist) for sensible quantities of money.

Pete.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net [email hidden] http://www.dundee.ac.uk/~pjclinch/

"Peter Clinch" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Roger said:

The secret is what they actually mean by Grid Reference. A secret you
apparently weren't in on and now suggest doesn't matter.

If I'm not in on it, then the fact that I can use maps and grids anyway is
yet another demonstration it's a non-issue.

Quoted message said:

There are 2 issues at stake. The first is the commonsense one that you
don't expect to be deliberately misinformed by purveyors of facts. The
second is that when you are aiming at something approximate you are
better off if your target is at the middle of the expected range, not
the extreme end.

But if you're at a suitable degree of accuracy then it's more or less on
it anyway.

If you want to convince me (or anyone else) this is a genuine problem it
would help if you could highlight, preferably with real map example(s),
how a feature will easily get lost or the wrong one picked up because of
using one assumption rather than the other. I don't think it's a problem
because I've never come across such a thing happening, and that you've
never yet highlighted problems beyond abstract theoretical ones suggests
to me that you haven't either. Otherwise you can go through life worrying
about it and I'll just do my navigation without Big Secrets, but knowing
where I am and finding where I'm going anyway...

This discussion is a repeat of one a while ago AFAICR. The conclusion being
reached is the same, I think. *In theory* Roger is right, *in practice* it
has no discernible effect, as Pete says. The OS aren't "deliberately seeking
to misinform", they are (openly) using a system which is (no doubt) easier
and cheaper for them, having made a judgement that *in practice* it will
make no difference to map users, while at least advertising the fact to
those who are interested. We have some of the best maps in the world and the
point under discussion makes not a jot of difference to that! Rejoice and
just use them!

--
Bob Mannix
(anti-spam is as easy as 1-2-3 - not)

Bernard Hill said:

In article <[email hidden]>, Dominic Sexton
<[email hidden]> writes

Quoted message said:

In article <[email hidden]>, Craig
Wallace <craigw84@fast_NOSPAM_mail.fm> writes

They do have some navigation features (goto and following saved tracks)
but don't do grid refs only lat / long in WGS-84.

Quoted message said:

Exactly. I can't find one whose adverts say "grid reference". You'd
think that was pretty basic, but it seems not...

There are some that don't say it in the adverts but still do it,
simply because it's not a popular feature, esp in the US. You need to
check the manuals.

--
Chris Malcolm [email hidden] DoD #205
IPAB, Informatics, JCMB, King's Buildings, Edinburgh, EH9 3JZ, UK
[http://www.dai.ed.ac.uk/homes/cam/]

Bernard Hill said:

In article <[email hidden]>, Craig
Wallace <craigw84@fast_NOSPAM_mail.fm> writes

Quoted message said:

Bernard Hill wrote:

Quoted message said:

Quoted message said:

Quoted message said:

There has to be a cheap GPS which has a readout as a grid ref.
I don't need maps, got those. I don't need track saving, I got maps.
I don't need direction, I got a compass.
But just now and again I get "lost" on a featureless flat top in the
cloud and would love to know where I am as a simple grid reference.

Cheapest and simplest option would be a basic Garmin eTrex or a Geko
201. Both have much the same features, the main difference is the Geko
is smaller and uses AAA batteries. Both are available for less than #100.
Or there's the new eTrex H, which has much the same features, plus a
new high sensitivity receiver. I'm not sure if it has actually been
released yet.

Paul mentioned wrist mounted GPS devices. The Garmin Foretrexs can
display a grid reference (they are much the same as the Geko, but in a
different form factor), but I don't think the Forerunner series can
give a grid ref (they are designed more for training, so lacking in
navigation features).

Quoted message said:

I'll look out for that. But I was hoping to get under #50 since the
electronics obviously comes that sort of price.

Years ago I got a new yellow eTrex (second generation) for 60 quid on
a discounted offer. I'd be surprised if you couldn't do better than
that today if you sniffed around. And there's always plenty on eBay.

--
Chris Malcolm [email hidden] DoD #205
IPAB, Informatics, JCMB, King's Buildings, Edinburgh, EH9 3JZ, UK
[http://www.dai.ed.ac.uk/homes/cam/]

The message <[email hidden]>
from Peter Clinch <[email hidden]> contains these words:

Sorry for the delay in replying but I have spent much of today driving
round in ever decreasing circles.

Quoted message said:

Quoted message said:

The secret is what they actually mean by Grid Reference. A secret you
apparently weren't in on and now suggest doesn't matter.

Quoted message said:

If I'm not in on it, then the fact that I can use maps and grids anyway
is yet another demonstration it's a non-issue.

You were under the impression that the instructions on the OS maps are
directions to their version of a grid a grid reference. As long as you
are consistent in your practice you cannot go wrong but any interaction
with someone not of the same persuasion could cause a misunderstanding.

Quoted message said:

Quoted message said:

There are 2 issues at stake. The first is the commonsense one that you
don't expect to be deliberately misinformed by purveyors of facts. The
second is that when you are aiming at something approximate you are
better off if your target is at the middle of the expected range, not
the extreme end.

Quoted message said:

But if you're at a suitable degree of accuracy then it's more or less on
it anyway.

An error on the ground of 140m is not exactly small beer and if you are
aiming off as well you might run out of patience before getting to where
you think you want to go.

Quoted message said:

If you want to convince me (or anyone else) this is a genuine problem it
would help if you could highlight, preferably with real map example(s),
how a feature will easily get lost or the wrong one picked up because of
using one assumption rather than the other. I don't think it's a
problem because I've never come across such a thing happening, and that
you've never yet highlighted problems beyond abstract theoretical ones
suggests to me that you haven't either. Otherwise you can go through
life worrying about it and I'll just do my navigation without Big
Secrets, but knowing where I am and finding where I'm going anyway...

When I started Munro bagging mumble mumble years ago Munros Tables were
out of print (and Munro bagging best kept a secret if you wanted to
avoid the derision of your acquaintances) so one had to guess what was
or was not a Munro. When a few years later the 1969 tables were
published I was surprised to find that the stated position was a 4
figure grid reference. Nowhere in the introduction does it say which
flavour the reference in and I am pretty sure that back in the 60s I
wasn't aware of the about face by the OS. A kilometre square is a big
enough area to through up several likely summits even before the
unresolved question of which particular square comes into play. All I
can recall from that time is confusion but luckily the 1974 edition with
6 figure references soon came along.

These days lists of peaks are everywhere and your guess is as good as
mine as to which flavour of grid reference they use as I don't think any
of them spell it out. And there a surprising number of peaks with
multiple summits of approximately the same height all within 140m of
each other.

Using a gps doesn't necessarily help overmuch. In entering a 6 figure
reference do you add 00 to each co-ordinate or 50?

--
Roger Chapman
Nearest Marilyn still to be visited - Great Orme.
89 miles as the crow flies,
considerably more as the walker drives.

The message <[email hidden]>
from "Bob Mannix" <[email hidden]> contains these words:

Quoted message said:

This discussion is a repeat of one a while ago AFAICR. The conclusion being
reached is the same, I think. *In theory* Roger is right, *in practice* it
has no discernible effect, as Pete says. The OS aren't "deliberately
seeking
to misinform", they are (openly) using a system which is (no doubt) easier
and cheaper for them, having made a judgement that *in practice* it will
make no difference to map users, while at least advertising the fact to
those who are interested. We have some of the best maps in the world
and the
point under discussion makes not a jot of difference to that! Rejoice and
just use them!

Would you care to point me towards the place where the OS advertises the
fact that they expect the general public to truncate their co-ordinates
rather take their best guess in order to confirm to the OS belief that a
grid reference absolutely relates to the Square to the NE of the Point.

--
Roger Chapman
Nearest Marilyn still to be visited - Great Orme.
89 miles as the crow flies,
considerably more as the walker drives.

The message <[email hidden]>
from Chris Malcolm <[email hidden]> contains these words:

Quoted message said:

Quoted message said:

Quoted message said:

They do have some navigation features (goto and following saved tracks)
but don't do grid refs only lat / long in WGS-84.

Quoted message said:

Quoted message said:

Exactly. I can't find one whose adverts say "grid reference". You'd
think that was pretty basic, but it seems not...

Quoted message said:

There are some that don't say it in the adverts but still do it,
simply because it's not a popular feature, esp in the US. You need to
check the manuals.

AFAICT the common or garden variety of in car sat-nav typically doesn't
do grid refs. That's why I ended up with a Garmin one which did at least
offer the option even if it is a PITA to use.

--
Roger Chapman
Nearest Marilyn still to be visited - Great Orme.
89 miles as the crow flies,
considerably more as the walker drives.

Peter Clinch said:

My guess is OS use a square system as the accuracy and resolution go
hand in hand. A 4 figure ref gives you a 1km square, and you know
it's that because it's a 4 figure reference.

Yes, and that's a very handy system. With OziExplorer I can overlay a 1km
grid with 100m subdivisions so I can see the 6 figure squares easily too,
far more easily than estimating them.

Quoted message said:

If you give a
co-ordinate then it's always a point and you can't tell from a point
what sort of accuracy or resolution you're talking about.

If by "co-ordinate" you mean a 6 figure GR, then no, that's not a point,
it's a 100m wide square.

Quoted message said:

Once you get down to 10 figures it's effectively the same thing in
any case.

Yes, not a problem in that case. I think of 10 figure grid refs (typically
used by GPS) as points, and 6 figure grid refs as squares.

Paul
--
http://www.wilderness-wales.co.uk/
http://www.wilderness-wales.co.uk/weblog/

Roger said:

Quoted message said:

It's described on every map, so it's not /that/ secret.

You may think that, but that is not actually the case. The natural
meaning of "Estimate tenths Eastward ..." is to make the most accurate
guess at the actual distance, not to stop at the invisible grid lines
just prior to the point.

Indeed. I never really thought about that years ago, but since it's been
pointed out, the wording is actually quite vague.

Quoted message said:

It is often necessary to refer to areas for tactical purposes. The
area of a square may be indicated by the S.W. corner - e.g Bivouac
area squares Q.70 and Q.71 - or squares 7363 and 7463 (according to
scale)."

Very handy for artillery, which by definition is "area fire" rather than
fire at a specific target.

Quoted message said:

Quoted message said:

If I say "the summit at [censored] yyy" folk will go
to more or less [censored] yyy and look around intelligently for summits,
rather than take out the verniers and ascertain that actually there
is
no summit at that exact location. While this is done on the fly by
human data processing, whether or not you consciously think of
squares
or points, it actually fits the square model better: go to an /area/
and look inside it. It works with a map because it's a highly
selective presentation of data, and often where the symbols take up
far more space than the feature really does on the ground.

Funnily enough I don't see it that way. I go to a point and look
around it.

I agree. The square concept works well if you're dividing a map into
squares, but when out walking looking for a point feature, one naturally
expects the grid ref to refer the the point, not the area containing it.

Quoted message said:

With a 6 figure grid ref the maximum displacement error on
the square system is about 140m while that with the point system is
half that.

Indeed.

Paul

--
http://www.wilderness-wales.co.uk/
http://www.wilderness-wales.co.uk/weblog/

Roger said:

These days lists of peaks are everywhere and your guess is as good as
mine as to which flavour of grid reference they use as I don't think
any of them spell it out.

If you compare Dawson to Dewey you'll find that many of the same summits
have different 6 figure GRs. After close examination it's clear that Dawson
uses the SW corner while Dewey tries to estimate the point itself. If you
use Dewey's grid refs and assume them to refer to a square rather than a
point, you'll often find yourself in the wrong square.

Quoted message said:

And there a surprising number of peaks with
multiple summits of approximately the same height all within 140m of
each other.

You really need at least 8 figures for those.

Quoted message said:

Using a gps doesn't necessarily help overmuch. In entering a 6 figure
reference do you add 00 to each co-ordinate or 50?

I routinely added 50 myself, but now I don't bother, I'd rather set a more
accurate GR for myself. In these days of GPS and digital mapping, I've no
longer got any use for 6 figure GRs anymore, I don't see why anyone with a
GPS would bother with them, unless they have no alternative. No doubt
they're still handy for map and compass users who seem to enjoy that lack of
accuracy, but once you've got used to using a GPS and routinely getting to
within 10m of a point, it's very hard to go back to 6 figure GRs. In fact, I
now consider an error of 30 or 40m to be appallingly bad.

Of course, in practice this isn't a problem in clear visibility, but at
night or in very thick fog, it can sometimes be an issue.

Paul
--
http://www.wilderness-wales.co.uk/
http://www.wilderness-wales.co.uk/weblog/

Bernard Hill said:

Quoted message said:

They do have some navigation features (goto and following saved
tracks) but don't do grid refs only lat / long in WGS-84.

Exactly. I can't find one whose adverts say "grid reference". You'd
think that was pretty basic, but it seems not...

Don't forget that most GPS units are designed for the world market, and most
countries seem to have different datums and coordinate systems, so the unit
has to be loaded with hundreds of datums and grid systems.

So it's not simply a matter of switching from lat/long to grid ref. It would
be, if a GPS was designed to be used only in the UK, but then you'd be
stuffed if you wanted to take it on holiday to another country.

Paul
--
http://www.wilderness-wales.co.uk/
http://www.wilderness-wales.co.uk/weblog/

Tom Crispin said:

Quoted message said:

Quoted message said:

I don't need maps, got those. I don't need track saving, I got
maps. I don't need direction, I got a compass.

That's a bit like saying you want to buy a car but you don't want
one with seats, windows or doors!

No. It's a bit like saying you want a vehicle to save time to get the
1000 yds each moring to the train station. A bicycle is the solution.

Yes, that's a good point.

Paul
--
http://www.wilderness-wales.co.uk/
http://www.wilderness-wales.co.uk/weblog/

The message <[email hidden]>
from "Paul Saunders" <[email hidden]> contains these words:

Quoted message said:

Quoted message said:

If you give a
co-ordinate then it's always a point and you can't tell from a point
what sort of accuracy or resolution you're talking about.

Quoted message said:

If by "co-ordinate" you mean a 6 figure GR, then no, that's not a point,
it's a 100m wide square.

To a mathematician a co-ordinate is one half of a grid reference. If you
really mean a square it is sloppy use of English to refer to
co-ordinates which must by definition define a point in a reference
system. To be fair to the OS they don't actually mention co-ordinates in
the message on their maps. You may find that message vague but wind the
clock back to a time when the civilian maps the OS produced had an A-Z
guide type grid and the instructions to those who used the military
maps, complete with national grid, made it clear that grid references
are co-ordinates except where specified as squares then the wording
isn't vague. The opposing viewpoint had not yet surfaced, at least in
the UK.

Another quote to emphasise the then military attitude:

"Emphasis in instruction should be put on lines rather than squares ...
The tendency to think in squares leads to three undesirable results:-"

Earlier I put forward NATO as a possible reason why the OS switched
systems but it is possible that they did it out of ignorance. AFAIK all
prewar OS civilian maps that had grids were restricted to grid systems
where co-ordinates were not an realistic option (how do you specify a
point in square C7?) and a casual view of the message by someone
habituated to squares could easily seem to fit the picture as Pete's
earlier response to me demonstrates.

--
Roger Chapman
Nearest Marilyn still to be visited - Great Orme.
89 miles as the crow flies,
considerably more as the walker drives.

"Bernard Hill" <[email hidden]> schreef in bericht
news:[email hidden]...

Quoted message said:

In article <[email hidden]>, Dominic Sexton
<[email hidden]> writes

Quoted message said:

In article <[email hidden]>, Craig
Wallace <craigw84@fast_NOSPAM_mail.fm> writes

They do have some navigation features (goto and following saved tracks)
but don't do grid refs only lat / long in WGS-84.

Exactly. I can't find one whose adverts say "grid reference". You'd think
that was pretty basic, but it seems not...

I don't see a problem. My Geko 201 gives me a grid reference and I suppose
the cheapest 101 does the same. Second hand it'll come even cheaper.

--
"Beannachd leibh"

Theo
www.theosphotos.fotopic.net

"Roger" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

The message <[email hidden]>
from "Bob Mannix" <[email hidden]> contains these words:

Quoted message said:

This discussion is a repeat of one a while ago AFAICR. The conclusion
being
reached is the same, I think. *In theory* Roger is right, *in practice*
it
has no discernible effect, as Pete says. The OS aren't "deliberately
seeking
to misinform", they are (openly) using a system which is (no doubt)
easier
and cheaper for them, having made a judgement that *in practice* it will
make no difference to map users, while at least advertising the fact to
those who are interested. We have some of the best maps in the world
and the
point under discussion makes not a jot of difference to that! Rejoice and
just use them!

Would you care to point me towards the place where the OS advertises the
fact that they expect the general public to truncate their co-ordinates
rather take their best guess in order to confirm to the OS belief that a
grid reference absolutely relates to the Square to the NE of the Point.

http://www.ordnancesurvey.co.uk/oswebsite/gi/nationalgrid/nationalgrid.pdf

Perhaps "advertise" was too strong a description but then so is
"deliberately misinform"

--
Bob Mannix
(anti-spam is as easy as 1-2-3 - not)

Roger said:

You were under the impression that the instructions on the OS maps are
directions to their version of a grid a grid reference. As long as you
are consistent in your practice you cannot go wrong but any interaction
with someone not of the same persuasion could cause a misunderstanding.

As I've pointed out several times, I use either assumption completely
interchangeably as I find it makes no effective difference on the ground.

Quoted message said:

An error on the ground of 140m is not exactly small beer and if you are
aiming off as well you might run out of patience before getting to where
you think you want to go.

If people didn't work relatively that might be a problem, but they do,
so it typically isn't. For example, if I'm going towards a summit I
work out my eventual location not from a grid reference but from the
ground: does it go up just over there? Yes. Then I cannot be at the
summit yet. QED.

Quoted message said:

These days lists of peaks are everywhere and your guess is as good as
mine as to which flavour of grid reference they use as I don't think any
of them spell it out. And there a surprising number of peaks with
multiple summits of approximately the same height all within 140m of
each other.

I haven't actually ever met anyone who will go to a plateau summit and
not wander around a little... As we've seen from resurveys in the past,
if you want to be sure you'd best visit anything possible in the
immediate neighbourhood anyway. And your 140m assumes that anyone
actually measures things exactly for a GR. I think in practically all
cases it's an eyeball estimation, so you'll have a similar degree of
error in either case.

Quoted message said:

Using a gps doesn't necessarily help overmuch. In entering a 6 figure
reference do you add 00 to each co-ordinate or 50?

If you take them off the map then you can do whatever you want. I
imagine you will have a map of where you're going, and check it just in
case whoever provided the reference has slightly different eyeballing
results to you?

Most of the battle here is realising that the information you have is
not *necessarily* as accurate as you're assuming it is. If I take [censored]
yyy off a page and decide to go there it is incumbent on me to look at
the map first and think about it, rather than turn up nearby and claim
it's all the OS's fault I'm not *exactly* where I want to be.

Pete.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net [email hidden] http://www.dundee.ac.uk/~pjclinch/

The message <[email hidden]>
from "Bob Mannix" <[email hidden]> contains these words:

Quoted message said:

Quoted message said:

Would you care to point me towards the place where the OS advertises the
fact that they expect the general public to truncate their co-ordinates
rather take their best guess in order to confirm to the OS belief that a
grid reference absolutely relates to the Square to the NE of the Point.

Quoted message said:

http://www.ordnancesurvey.co.uk/oswebsite/gi/nationalgrid/nationalgrid.pdf

I did ask for a place for the general public to be informed, not
Internet nerds, but I can't see anything in the cited site that actually
does identify a grid reference as a square. It doesn't help that the
site seems aimed at children with a reading age of 10 and simplified to
the detriment of both good English and detail.

Good English? If I see "Unique reference system" I expect a unique
system not one that will generate a unique reference.

Detail? The two letter prefix usually used for full grid references
comes from the combination of 500 km squares and 100 km squares (both
consisting of 25 letters of the alphabet in five rows of five) rather
than the almost random scatter that reference only to 100 km squares and
illustrating only significant squares implies. And the only hint of the
alternative fully numerical reference is the numbering on the map
detailing the significant letter squares.

OK so it bangs on about squares but the letter system is just a more
convenient way of making the local grid reference unique and when the
explanation gets on to 6 figure references it is still down to the
"Estimate tenths Eastward ..." format that was originally used for
points.

You can't rely on the "accurate to within 100m" either. Strictly
speaking neither flavour has that particular accuracy but the wording
"to the nearest 100m" which is what we find on maps was a feature of the
British System that presumably dates back to 1919, several decades
before civilian maps gained a national grid and the wherewithal for
co-ordinates.

Quoted message said:

Perhaps "advertise" was too strong a description but then so is
"deliberately misinform"

If you know the facts but choose to suggest they actually mean something
else then that is either deliberate or accidental. In either case it is
misinformation. So I wouldn't discount the notion that it is largely
accidental but I find it impossible to believe that some time or another
since the late 40s someone in control of map making at the OS was aware
of the full facts and chose not to do anything about it.

--
Roger Chapman
Nearest Marilyn still to be visited - Great Orme.
89 miles as the crow flies,
considerably more as the walker drives.

Paul Saunders said:

If by "co-ordinate" you mean a 6 figure GR, then no, that's not a point,
it's a 100m wide square.

By "co-ordinate" I mean exactly what I say: it's a point.

Quoted message said:

Quoted message said:

Once you get down to 10 figures it's effectively the same thing in
any case.

Yes, not a problem in that case. I think of 10 figure grid refs (typically
used by GPS) as points, and 6 figure grid refs as squares.

But Roger's point is that you don't really know where the square starts.
With a 4 figure ref we all seem to know it's the SW corner of the
square, but is that true for 6 figure refs too? And he's right, it
isn't clear. Where we differ is that he thinks it matters a lot and I
don't think it does. If folk were looking for exact points that didn't
stick out from their surroundings with 6 figure refs I'd say fair
enough, but IME they're not.

Pete.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net [email hidden] http://www.dundee.ac.uk/~pjclinch/

"Roger" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

The message <[email hidden]>
from "Bob Mannix" <[email hidden]> contains these words:

Quoted message said:

Quoted message said:

Would you care to point me towards the place where the OS advertises
the
fact that they expect the general public to truncate their co-ordinates
rather take their best guess in order to confirm to the OS belief that
a
grid reference absolutely relates to the Square to the NE of the Point.

Quoted message said:

http://www.ordnancesurvey.co.uk/oswebsite/gi/nationalgrid/nationalgrid.pdf

I did ask for a place for the general public to be informed, not
Internet nerds, but I can't see anything in the cited site that actually
does identify a grid reference as a square. It doesn't help that the
site seems aimed at children with a reading age of 10 and simplified to
the detriment of both good English and detail.

Good English? If I see "Unique reference system" I expect a unique
system not one that will generate a unique reference.

You didn't ask for something with good English or acceptable detail. One
might also say that the only people with such an overwhelming interest in
something that clearly isn't a problem in real life (I am with Pete on this
one) might just be "map nerds" and dismiss them in a similarly cavalier
fashion :o)

Nowhere (as far as I can see) do they claim they are using exact coordinates
rather than the SW corner of a square, so they are NOT deliberately
misinforming (whatever other failings they may have, and I'm sure thay are
failings). Most people (including the OS) don't think it matters in the real
lives of their map users but, if you ask them to clarify the GR system, I
have no doubt they would explain it without misinformation!

It would seem to be the case that you care and others, even if they didn't
already know and have it carefully explained to them, don't. There is,
therefore, unlikely to be a resolution!

Bob