UKC

Hi,
Does anyone know if a six digit OS grid ref can be used with a GPS? Compatable?

Thanks

In reply to PaulTanton:

yes, of course, though you may have to go rooting in the settings menu if it isn't already configured for this - even my old etrex can manage this.

In reply to PaulTanton:

Just add 00 after the first three numbers and at the end i.e. 12300 45600.

In reply to PaulTanton:

You have to have your GPS set to the right datum and coordinate reference system (CRS). The National Grid as used on OS maps is based on the OSGB36 Datum using the Airy 1830 ellipsoid. Although the OS now works in terms of WGS84 Datum (having replaced the traditional trig points with a set of GPS reference points) the datum in use on maps is still OSGB36 and the newer OS WGS84 GPS coordinates are transformed to this for mapping.

So as long as your GPS receiver has the option to display or enter coordinates in "UK National Grid/ OSGB36 Datum", then yes, it's compatible. Almost all hand-held GPS units sold in the UK (but not usually your phone or in-car GPS) will have the option somewhere in the settings menu.

In reply to Rob Naylor:

As Rob says.

Also note that a six-figure grid denotes a 100mx100m square. Chances are that your GPS will want you to input a ten-figure grid ( e.g. AB12345 12345 as OwenM says), which would be a 1mx1m square. Don't be surprised if your GPS takes you to a very specific point a few dozen metres away from whatever point it is you are trying to find.

In reply to richprideaux:

I reckon using the software (or already known location) rather than the paper map can have a resolution of 10x10m grid. I guess it all depends on the intended use.

When I stash my overnight gear while hillwalking, I sometimes record the location on my phone using Viewranger (or previously Alpine Quest when I had Android). When you are about to leave your stuff, "that third boulder from that tree is so obvious" becomes quite vague description hours later...

In reply to Rob Naylor:

Garmin car talkie navigating GPSs will also accept BNG.

In reply to PPP:

Software? I don't follow you... A 10mx10m accuracy would be an eight-figure grid, which is about as good as you'll get from a 1:25k OS paper map, but the OP was asking about inputting a six-figure grid into a GPS? There is a good chance I am being thick here though

The point I wanted to make was the significant difference between a six-figure grid (as commonly quoted when talking about locations) and a ten-figure grid (as normally used by GPS datums etc). You can easily make a six-figure into a ten-figure by adding zeroes after each group of numbers, but that will put the position into the SW corner of the original 100mx100m square, when the person working out the original six-figure grid ref might have been talking about the NE corner.

In reply to richprideaux:

You know that feeling when you think about something for few minutes, draw conclusions and write some gibberish on the forum because you think you had a conversation about something you were thinking on your own? Yeah, that's what I just did. Sorry about that.

What I wanted to say was that you can get a more accurate than 6 figure grid reference if you use some software (that's obvious!). Figuring out six-figure grid out of a map without a ruler won't be accurate (my Silva compass has both 1:25k and 1:50k rulers, but god Harvey maps are using 1:40k). However, if you can get an accurate grid reference before setting off, then you can have more than 100mx100m resolution.

In reply to this thread:

thankyou UKC, I've just got Alpinequest to give me OS grid refs, woohooo

In reply to PPP:


Navigational note: newer Silva compasses have 1:40 romers.

In reply to PaulTanton:

It's all very well a GPS giving you a ten figure reference, which would give you a 1m x 1m square on the ground, but 1:50 000 or 1:25 000 maps aren't drawn to anything like that accuracy. Unless roads are 300m wide.

In reply to OwenM:

Not all navigation is done by feature extraction from maps, though... You could use your GPS to survey points, and return to them. A 1m square is easier to find something in than a 100m square. Granted, your GNSS receiver is unlikely to be accurate to 1m...

Geocaching, archaeological feature surveying, etc, use this concept. Even caching gear.

In reply to PaulTanton:

On a GNSS-equipped Android phone, try the 'Grid Reference' app. It does what it says on the tin... 6, 8 or 10 figures.

In reply to OwenM:
"unless roads are 300m wide"

thats not really true though. Thats the art of cartography, enhancing, or exagerrating important features for the benefit of the user, different features are important to different users. So the road might not be to scale but that is a sacrifice that is made so the map is optimized.

In reply to climbwhenready:


And very helpful I've found it when using Harvey's map.

In reply to richprideaux:

You could put 5 s for the middle of the square.