Long/Lat to OS Grid Ref

Bitstring <[email hidden]>, from the wonderful person Nigel C
<[email hidden]> said

Quoted message said:

Hi, I thought this would be an easy google search but I'm not having
much luck or I'm being a numpty.

Is there a site or a free programme that will let me enter Latitude and
Longitude and output the UK OS grid reference? I've found a site that
lets me do the reverse operation
http://www.obliquity.com/astro/osgb.html but that's not what I want.

I don't have a gps or Memory Map.

Sorry if it's a basic question.

You want 'grid inquest' which is a free download vaguely associated with
the OS. There is a set of .dll files as well in case you want to use it
in a program. Try here:

http://www.qgsl.com/?product=gridinquest

--
GSV Three Minds in a Can
9,423 Km walked. 1,827Km PROWs surveyed. 33.2% complete.

Nigel C said:

Hi, I thought this would be an easy google search but I'm not having
much luck or I'm being a numpty.

Is there a site or a free programme that will let me enter Latitude
and Longitude and output the UK OS grid reference? I've found a site
that lets me do the reverse operation
http://www.obliquity.com/astro/osgb.html but that's not what I want.

GPSUtility will do this.
It stores data in a text file, in a very easy to understand format. Might
be easiest to manually enter one or two points (waypoints) in the GPSUtility
interface, then save the file.
Then quit, enter all your data in the text file.
Then restart, and click onto the format you wish to convert to.

I'm sure there are other tools and other methods.

- Nigel

--
Nigel Cliffe,
Webmaster at http://www.2mm.org.uk/

Nigel C said:

Is there a site or a free programme that will let me enter Latitude
and Longitude and output the UK OS grid reference? I've found a site
that lets me do the reverse operation
http://www.obliquity.com/astro/osgb.html but that's not what I want.

I don't have a gps or Memory Map.

Both GSV and Nigel are correct, Grid Inquest and GPS Utility will do the
job, however they'll produce different results. The question is what do you
want to use these grid refs for, and what's the source of your lat/longs?

Grid Inquest will produce a very accurate conversion, but it's not suitable
for use with a GPS.

GPS Utility (and most other GPS & mapping software) uses a simple conversion
which produces an inaccurate result, but it's pretty much the same as the
conversion done internally in a GPS, so it's accurate for GPS use.

You say you don't have a GPS, so you probably need the first one, unless you
want to convert the grid refs for others to use with a GPS.

Also, what's the source of these lat/longs? Are they UK (OS datum) or US
(WGS84 datum)? Each is different, so you need to be sure which datum is used
if you want an accurate conversion.

Paul

Paul Saunders said:

Nigel C said:

Is there a site or a free programme that will let me enter Latitude
and Longitude and output the UK OS grid reference? I've found a site
that lets me do the reverse operation
http://www.obliquity.com/astro/osgb.html but that's not what I want.

I don't have a gps or Memory Map.

Both GSV and Nigel are correct, Grid Inquest and GPS Utility will do the
job, however they'll produce different results. The question is what do you
want to use these grid refs for, and what's the source of your lat/longs?

Just hovering my mouse in Google Earth. Don't laugh!

Quoted message said:

Grid Inquest will produce a very accurate conversion, but it's not suitable
for use with a GPS.

GPS Utility (and most other GPS & mapping software) uses a simple conversion
which produces an inaccurate result, but it's pretty much the same as the
conversion done internally in a GPS, so it's accurate for GPS use.

You say you don't have a GPS, so you probably need the first one, unless you
want to convert the grid refs for others to use with a GPS.

Also, what's the source of these lat/longs? Are they UK (OS datum) or US
(WGS84 datum)? Each is different, so you need to be sure which datum is used
if you want an accurate conversion.

Thanks. I didn't know that. Quite simply I wanted to let someone know,
who doesn't have a computer but the relevant OS maps which I don't have,
approximate grid references of a few places.

Cheers all.

Nigel C said:

Hi, I thought this would be an easy google search but I'm not having
much luck or I'm being a numpty.

Is there a site or a free programme that will let me enter Latitude and
Longitude and output the UK OS grid reference? I've found a site that
lets me do the reverse operation
http://www.obliquity.com/astro/osgb.html but that's not what I want.

I don't have a gps or Memory Map.

Sorry if it's a basic question.

Is this what you want?
http://gps.ordnancesurvey.co.uk/convert.asp

There is a mathematical formula for the conversion, but I haven't been
able to find it.

Bitstring <[email hidden]>, from the wonderful person Nigel C
<[email hidden]> said

Quoted message said:

Paul Saunders said:

Nigel C said:

Is there a site or a free programme that will let me enter Latitude
and Longitude and output the UK OS grid reference? I've found a site
that lets me do the reverse operation
http://www.obliquity.com/astro/osgb.html but that's not what I want.

I don't have a gps or Memory Map.

Both GSV and Nigel are correct, Grid Inquest and GPS Utility will do
the job, however they'll produce different results. The question is
what do you want to use these grid refs for, and what's the source of
your lat/longs?

Just hovering my mouse in Google Earth. Don't laugh!

Quoted message said:

Grid Inquest will produce a very accurate conversion, but it's not
suitable for use with a GPS.
GPS Utility (and most other GPS & mapping software) uses a simple
conversion which produces an inaccurate result, but it's pretty much
the same as the conversion done internally in a GPS, so it's accurate
for GPS use.
You say you don't have a GPS, so you probably need the first one,
unless you want to convert the grid refs for others to use with a GPS.
Also, what's the source of these lat/longs? Are they UK (OS datum)
or US (WGS84 datum)? Each is different, so you need to be sure which
datum is used if you want an accurate conversion.

Thanks. I didn't know that. Quite simply I wanted to let someone know,
who doesn't have a computer but the relevant OS maps which I don't
have, approximate grid references of a few places.

Unless you are giving 10 figure references any of the above will work.
If you want cm accuracy you better use Grid Inquest (and be sure about
your datums, and your dates, given the way the tectonic plates keep
leaping around).

Putting stuff into / out of GPS systems is best done using WGS84 ..
their interpretation of OSGB (especially height) is, as Paul said,
pretty whacky sometimes. We don't get any special treatment over formats
like 'Indonesian Equatorial' or 'India Zone4B', or numerous other
strange types.

--
GSV Three Minds in a Can
9,423 Km walked. 1,827Km PROWs surveyed. 33.2% complete.

Bitstring <[email hidden]>, from the
wonderful person Tom Crispin <[email hidden]>
said

Quoted message said:

Nigel C said:

Hi, I thought this would be an easy google search but I'm not having
much luck or I'm being a numpty.

Is there a site or a free programme that will let me enter Latitude and
Longitude and output the UK OS grid reference? I've found a site that
lets me do the reverse operation
http://www.obliquity.com/astro/osgb.html but that's not what I want.

I don't have a gps or Memory Map.

Sorry if it's a basic question.

Is this what you want?
http://gps.ordnancesurvey.co.uk/convert.asp

There is a mathematical formula for the conversion, but I haven't been
able to find it.

For OSGB there isn't actually a formula (well, there is a very rough
one) because there are several places where there are 'tears' in the
overall grid, so there are some large lookup tables which says things
like 'if you're between X & Y places, add 4m to Easting and deduct 5m
from Northing'.

Even the basic formula is pretty horrific. e.g.

http://www.ordnancesurvey.co.uk/oswebsite/gps/information/coordinatesyste
msinfo/guidecontents/guide6.html

--
GSV Three Minds in a Can
9,423 Km walked. 1,827Km PROWs surveyed. 33.2% complete.

Paul Saunders said:

Nigel C said:

Is there a site or a free programme that will let me enter Latitude
and Longitude and output the UK OS grid reference? I've found a site
that lets me do the reverse operation
http://www.obliquity.com/astro/osgb.html but that's not what I want.

I don't have a gps or Memory Map.

Both GSV and Nigel are correct, Grid Inquest and GPS Utility will do the
job, however they'll produce different results. The question is what do you
want to use these grid refs for, and what's the source of your lat/longs?

Grid Inquest will produce a very accurate conversion, but it's not suitable
for use with a GPS.

GPS Utility (and most other GPS & mapping software) uses a simple conversion
which produces an inaccurate result, but it's pretty much the same as the
conversion done internally in a GPS, so it's accurate for GPS use.

You say you don't have a GPS, so you probably need the first one, unless you
want to convert the grid refs for others to use with a GPS.

GPS Utility uses the same algorithm as consumer grade GPS units and
should give the same answer as a GPS within +/- 1 rounding error in
the last digit.

The Ordnance Survey 'definitive' value depends on a large mathematical
model which contains many megabytes of data. The largest error between
the algorithm and the definitive model is about 13m in north west
Scotland.

It is fairly easy to 'calibrate' the GPS Utility algorithmic
conversion so as to achieve sub-metre accuracy over a local area (i.e.
to agree with the definitive model). For further details of how to do
this, please see the Help topic in GPSU on 'Ordnance Survey grids'.
For GPS Utility see www.gpsu.co.uk.

Alan Murphy (author GPSU).

Nigel C said:

Hi, I thought this would be an easy google search but I'm not having
much luck or I'm being a numpty.

Is there a site or a free programme that will let me enter Latitude and
Longitude and output the UK OS grid reference? I've found a site that
lets me do the reverse operationhttp://www.obliquity.com/astro/osgb.htmlbut that's not what I want.

I don't have a gps or Memory Map.

Sorry if it's a basic question.

For online utilities try my site at:-

http://www.gpssharing.com/utilities/

or for loads of conversions

http://www.nearby.org.uk/

Plus make sure that the program you use does a correct transformation,
some use the wrong algorithm and give an error or around 100m.

Ted

Nigel C said:

Hi, I thought this would be an easy google search but I'm not having
much luck or I'm being a numpty.

Is there a site or a free programme that will let me enter Latitude and
Longitude and output the UK OS grid reference? I've found a site that
lets me do the reverse operation
http://www.obliquity.com/astro/osgb.html but that's not what I want.

I don't have a gps or Memory Map.

Sorry if it's a basic question.

http://www.streetmap.co.uk/ ??

Enter a long+lat, go to the location, and then let it convert it to
different units ('Click here to convert/measure coordinates'😉 near the
bottom of the page.

Nigel C said:

Hi, I thought this would be an easy google search but I'm not having
much luck or I'm being a numpty.

Is there a site or a free programme that will let me enter Latitude and
Longitude and output the UK OS grid reference? I've found a site that
lets me do the reverse operationhttp://www.obliquity.com/astro/osgb.htmlbut that's not what I want.

I don't have a gps or Memory Map.

Sorry if it's a basic question.

try this

http://www.nearby.org.uk/coord.cgi?p=51.5365951%2C+-0.7003251&f=full

also download the demo of memory map. Set the units to lat long.
Do a find and set leave mark . you will have a flag at the point. Set
the units to OS.
right click on the mark and do properties. The OS grid will be
displayed.

Alan Murphy said:

GPS Utility uses the same algorithm as consumer grade GPS units and
should give the same answer as a GPS within +/- 1 rounding error in
the last digit.

Thanks for clarifying that Alan. I'd noticed the occasional 1m discrepancy
between my GPS, GPSU and OziExplorer, so I wasn't sure if exactly the same
algorithm was being used.

Paul