OS Grid reference - how to find?

Quoted message said:

Yes, but if he grabs the largest scale screen image from getamap, he can use a ruler to measure
off to the accuracy he wants, since the grid lines are shown.

If the 1:50000 maps are good enough, just use www.streetmap.co.uk and read off the pixel coordinates
shown by the browser when moving the moose over the map. Divide by 2 (they are 5m pixels) and invert
the y value.

David

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

Quoted message said:

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

Quoted message said:

"RJ Webb" <[email hidden]> wrote in message news:3f8ac464.29414203@news-
text.blueyonder.co.uk...

Quoted message said:

On Mon, 13 Oct 2003 11:30:47 GMT, [email hidden] (maddening) wrote:

>I need to find my *exact* grid reference - is there a way to achieve this on the internet?
>
>I've tried streetmap.co.uk and that gives a certain reference when I've clicked on the
>location, but when I re-enter that ref (ie to verify it by searching for it) the location is
>a bit further away

than

Quoted message said:

Quoted message said:

Quoted message said:

>the one i originally found!
>
>Or am I better off just going out and buying a suitable map?
getamap.co.ukgetamap.co.ukOpen ↗ is a good one for this... The gr of the cursor appears below the tiny
map pane.

It may be good but not for what the OP asked - it gives a 3x3 figure reference, ie the corner of
a 100m box (several properties wide in my

road).

Quoted message said:

He wanted an exact reference for his property, so the 5x5 mentioned by

Phil

Quoted message said:

Cook would give a 1m box and you could round up to 4x4 to give a 10m

box.

Quoted message said:

Quoted message said:

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

Yes, but if he grabs the largest scale screen image from getamap, he can

use

Quoted message said:

a ruler to measure off to the accuracy he wants, since the grid lines are shown.

Seems like a good fast cheap answer to me.

Very true, but also of all such sites (eg streetmap.co.uk, which I prefer). I thought at first
getamap was going to be better in some way.

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

"Ian Dainty" <[email hidden]> wrote

Quoted message said:

I hate it when you pretend you know what you are talking about?

Was that a question!

Quoted message said:

Where's this blooming gift anyway?

Gift lad? It said gif on the picture, don't ask me what it means.......anyway, sod that, I've been
given time off for good behaviour 14/15/16 Nov. Fancy a hike over a mountain and several quarts of
ale? Can we do expedition 19b? What number are we up to? I've missed the last 7.......

Quoted message said:

G

"Chris" <proteus1@gmxDOTnet> wrote

Quoted message said:

a 6 figure grid reference will give you a position accurate to the nearest 100 metres...

an 8 figure grid reference will give you a position accurate to the nearest 10 metres...

No, he means the reference is to a square, ie the SW corner of that square and whatever you are
refering to is contained within the square, in which case you could be more than 100m away from your
target with a 6 figure reference. This is the convention that the OS has used while i have worked
there, although I have had some lengthy arguements with Roger, and I accept his view that another
convention could mean the reference was to the centre of your target.

Graham

Roger Chapman said:

Point of order. Grid references haven't been co-ordinates since the OS was persuaded to dump the
original notion and adopt the American system of asymmetric nesting squares. (Co-ordinates define
the position of a point, not an area).

Quoted message said:

Since the OS have never bothered to change the wording of the instruction on how to take a grid
reference nor publicize their betrayal of the original concept only those privy to the inner
workings of the OS mindset know that they have to truncate each element rather than round it in
order to get to their americanised reference. It would have been simplicity itself (and accurate)
to call such abortions Grid Squares rather than Grid References but I presume their american
masters wouldn't let them.

American Masters? Of the British OS? So why do we have to pay so much for our maps when the US has a
free national mapping service? How come such an important feature of national security as our maps
belongs to a Foreign Power? Is this a Communist plot? Aaarrggh! Nurse! My pills! Hurry!

--
Chris Malcolm [email hidden] +44 (0)131 651 3445 DoD #205
IPAB, Informatics, JCMB, King's Buildings, Edinburgh, EH9 3JZ, UK
["]http://www.dai.ed.ac.uk/homes/cam/]

On Tue, 14 Oct 2003 08:52:17 +0000 (UTC), [email hidden] (Chris

Malcolm) said:

Easier than sitting on the roof, and more accurate than projection, is to take refs from points
which will average to house centre, such as the corners of the house, or even better, points the
same distance away from the corners (better sky view). These points will *not* form a rectangle,
because of the biassed errors introduced by the bias in the skyview by the house.

I'm under the impression that the point to give a GR or bearing is;

Liner feature (Rivers, roads etc)= between the lines Column (Lighthouse, TV/radio Mast etc) is
central base. Symmetrical shape (Place of worship, buildings etc )= centre of shape

Dewi,

(remove spin for email)

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

Quoted message said:

Quoted message said:

Yes, but if he grabs the largest scale screen image from getamap, he can

use

Quoted message said:

Quoted message said:

a ruler to measure off to the accuracy he wants, since the grid lines

are

Quoted message said:

Quoted message said:

shown.

If the 1:50000 maps are good enough, just use www.streetmap.co.uk and read off the pixel
coordinates shown by the browser when moving the moose over the map. Divide by 2 (they are 5m
pixels) and invert the y value.

I like it!

Picky, I know, but you actually meant "subtract the y value from 100 to get the y value you want"
(200 if before the divide by 2) rather than "invert the y value"

I also notice that my browser (IE) runs out of characters on the bottom line and drops the less
significant figures of the y value, which I hadn't noticed before.

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

"Chris Malcolm" <[email hidden]> wrote

Quoted message said:

<cough>

And how, er, accurate, is the map?

</cough>

Actually, accurate enough for a 10m ref, which is what I presume the original poster meant by
*exact*. Any greater accuracy would probably require large scale mapping (expensive) or dGPS.

Graham

Graham Seed said:

anyway, sod that, I've been given time off for good behaviour 14/15/16 Nov. Fancy a hike over a
mountain and several quarts of ale? Can we do expedition 19b? What number are we up to?

14 is next.

There has been some talk of a wild camp at Llyn y Fan Fawr in the western Beacons sometime this
month but there's been the usual dithering and lack of commitment (wimps who are afraid to camp out
in the cold I reckon).

So there's *some* interest in doing that in the next few weeks, but there's also a rebel group
pushing for an early to mid-November trip instead (or maybe as well as?).

So how about Expedition 14 this month in the Beacons and Expedition 15 a few weeks later somewhere
else, maybe Mid-Wales?

After all, there's no rule that says we have to wait a few months in between each one, is there?

What does anyone think?

Paul
--
The October Project 2003
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Graham Seed said:

It said gif on the picture, don't ask me what it means.......

Graphical information format, devised by Compuserve.

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and dealers.

Graham Seed said:

"Chris" <proteus1@gmxDOTnet> wrote

Quoted message said:

Quoted message said:

a 6 figure grid reference will give you a position accurate to the nearest 100 metres...

an 8 figure grid reference will give you a position accurate to the nearest 10 metres...

Quoted message said:

No, he means the reference is to a square, ie the SW corner of that square and whatever you are
refering to is contained within the square, in which case you could be more than 100m away from
your target with a 6 figure reference. This is the convention that the OS has used while i have
worked there, although I have had some lengthy arguements with Roger, and I accept his view that
another convention could mean the reference was to the centre of your target.

Now that we have easy access to GPSRs which can supply grid refs as an estimate to a one metre
"point" (ok, square if you like) plus several metres probable error, the OS convention is somewhat
incovenient and out-dated.

--
Chris Malcolm [email hidden] +44 (0)131 651 3445 DoD #205
IPAB, Informatics, JCMB, King's Buildings, Edinburgh, EH9 3JZ, UK
["]http://www.dai.ed.ac.uk/homes/cam/]

Graham Seed said:

"Chris" <proteus1@gmxDOTnet> wrote

Quoted message said:

a 6 figure grid reference will give you a position accurate to the nearest 100 metres...

an 8 figure grid reference will give you a position accurate to the nearest 10 metres...

No, he means the reference is to a square, ie the SW corner of that square and whatever you are
refering to is contained within the square, in which case you could be more than 100m away from
your target with a 6 figure reference. This is the convention that the OS has used while i have
worked there, although I have had some lengthy arguements with Roger, and I accept his view that
another convention could mean the reference was to the centre of your target.

I make it 141 metres for a 6 figure reference.

Actually I'll often allow for a certain amount of error in the map when selecting which corner to
give! It can also be more useful to indicate the correct side of a linear feature!

David

"Graham Seed" <[email hidden]> wrote in message
"]news:[email hidden]

Quoted message said:

I've been given time off for good behaviour 14/15/16 Nov. Fancy a hike over a mountain and several
quarts of ale? Can we do expedition 19b? What number are we up to? I've missed the last 7.......

Quoted message said:

G

Sounds good. Especially the ale part. It must be two years since you've been along. Wasn't it the
Christmas 2001 meet at the Brecons? It snowed on the Sunday and it was a bit chilly in the tent
as I recall.

Ian.

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

Quoted message said:

American Masters? Of the British OS? So why do we have to pay so much for our maps when the US has
a free national mapping service? How come such an important feature of national security as our
maps belongs to a Foreign Power?

I have been unable to find out for sure but I am more than half convinced that the Americans forced
the change to truncated references, either during WW2, or when setting up NATO. Blair is by no means
the first Brit to imitate a doormat when faced with American demands. Frank Sinatra wasn't just
singing for himself with 'My Way'.

--
Roger Looking North over the Aire Valley (and Marley Gasworks) to Rombolds Moor Top Posters
killfiled on sight

The message <[email hidden]>
from "Graham Seed" <[email hidden]> contains these words:

Quoted message said:

"Chris" <proteus1@gmxDOTnet> wrote

Quoted message said:

Quoted message said:

a 6 figure grid reference will give you a position accurate to the nearest 100 metres...

an 8 figure grid reference will give you a position accurate to the nearest 10 metres...

Quoted message said:

No, he means the reference is to a square, ie the SW corner of that square and whatever you are
refering to is contained within the square, in which case you could be more than 100m away from
your target with a 6 figure reference. This is the convention that the OS has used while i have
worked there, although I have had some lengthy arguements with Roger, and I accept his view that
another convention could mean the reference was to the centre of your target.

It's ok Graham, I don't hold it against you personally for sticking to house rules but for someone
outside the OS the present system is counter intuitive to anyone with the slightest grounding in co-
ordinate geometry. The Americans go to great lengths on their OS website to dress up their system of
nesting squares as the best possible way of identifying a location completely oblivious to the
obvious clash with traditional co-ordinates or the strange way the target tracks SW as the the
reference becomes more precise.

The really galling thing our OS is that they had it right to begin with (or at least the War Office
did when civilian maps had nothing better than a local grid). As the layout and wording of the
instructions of how to give a grid reference were, until very recently, substantially the same as
the prewar War Office version it is not possible to tell when the OS adopted their current
convention.

One significant difference between the prewar War Office and the postwar OS is that the War Office
instruction was to give a grid reference to a

are we invited to take the West edge of the square in which the point lies and estimate tenths
Eastward. Now we have to "locate first VERTICAL grid line to LEFT of point .... estimate tenths from
grid line to point". But still no indication that the OS thinks that the tenths should be truncated
rather than rounded where necessary or that the result is intended to reflect a square rather than
that much emphasised point.

--
Roger Looking North over the Aire Valley (and Marley Gasworks) to Rombolds Moor Top Posters
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On Wed, 15 Oct 2003 10:32:35 +0100, Gordon <[email hidden]>

Quoted message said:

Paul Rooney <[email hidden]> wrote

Quoted message said:

Martin Richardson said:

In article <[email hidden]>, Ian Dainty
<[email hidden]> writes
>"Martin Richardson" <[email hidden]> wrote in message
>"]news:[email hidden]
>
>> >Or am I better off just going out and buying a suitable map?
>> >
>> Why not use a GPS?
>
>Expensive option Martin.
>
>Just call Mountain Rescue on your mobile. They can get a fix on your signal and tell you where
>you are.
>
Or paint a large white cross on your roof and get someone in a space shuttle to give you a co-
ordinate.

But preferably not an American.

I was about to post that when I realise that it was a despicable slur on our greatest allies, who
have bailed us out of 17 world wars, paid for everything we own, given us MacDonalds gourmet food
and Coca Cola to keep our fat and sugar levels up and, and . . .

You have a real nice day, now...

Yes. They can't help it if they take a 'broad brush' approach to hitting a target (-:

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Wainwrights

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Quoted message said:

I also notice that my browser (IE) runs out of characters on the bottom line and drops the less
significant figures of the y value

Actually it will be chopping an great chunk out of the middle at hat point. Mozilla seems to chop at
the same place!

Either:
1) Use a wider window
2) Delete most of the [censored] from the URL

(z=4 gives you a 5x5 image instead of the usual 3x3)

David

Gordon said:

I was about to post that when I realise that it was a despicable slur on our greatest allies, who
have bailed us out of 17 world wars, paid for everything we own, given us MacDonalds gourmet food
and Coca Cola to keep our fat and sugar levels up and, and . . .

you forgot to mention GPS.

Paul
--
The October Project 2003
wildwales.fsnet.co.ukoctober.htmlOpen ↗
wilderness-wales.co.ukwilderness-wales.co.ukOpen ↗
photosig.comuserphotosOpen ↗

Paul Saunders said:

Graham Seed said:

anyway, sod that, I've been given time off for good behaviour 14/15/16 Nov. Fancy a hike over a
mountain and several quarts of ale? Can we do expedition 19b? What number are we up to?

14 is next.

There has been some talk of a wild camp at Llyn y Fan Fawr in the western Beacons sometime this
month but there's been the usual dithering and lack of commitment (wimps who are afraid to camp out
in the cold I reckon).

I'm up for this one. Need a date soon though so I can book time off.

Quoted message said:

So there's *some* interest in doing that in the next few weeks, but there's also a rebel group
pushing for an early to mid-November trip instead (or maybe as well as?).

So how about Expedition 14 this month in the Beacons and Expedition 15 a few weeks later somewhere
else, maybe Mid-Wales?

After all, there's no rule that says we have to wait a few months in between each one, is there?

What does anyone think?

Paul

--
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looking at flat fields and that includes the castle.

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

Quoted message said:

So there's *some* interest in doing that in the next few weeks, but there's also a rebel group
pushing for an early to mid-November trip instead (or maybe as well as?).

What is needed is someone who is keen enough to decide where and when and then push. You will never
pick either a time or a place that will suit all of us but large gatherings can have their downside
anyway so get on with it. Since Chris B went quiet no one has popped up to take his place as the
driving force.

Quoted message said:

So how about Expedition 14 this month in the Beacons and Expedition 15 a few weeks later somewhere
else, maybe Mid-Wales?

If you go ahead with the Lyn y Fan Fawr meet I might wander up and have a chat sometime but for most
of the weekend I will be otherwise engaged. As for November ISTR that can be a miserable month (but
not as miserable as December). I might manage it if I can tear myself away from my primary objective
of completing the Wainwrights before Paul R.

Quoted message said:

After all, there's no rule that says we have to wait a few months in between each one, is there?

Certainly not.

Quoted message said:

What does anyone think?

I haven't a clue. :-)

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