Maps! Such useful things - in the right hands. However, in the wrong hands (more precisely, when used wrongly) they can get you into all sorts of trouble.

Not for David Burgess, though, who was chosen randomly from the 44 correct entries to win a copy of David Simmonite's "Rock Climbing In England And Wales". Commiserations to everyone else who tried - but take some encouragement from the fact that your efforts have helped improve UKClimbing.

Why? Why did we have a competition in which you had to fill in the map reference of the bottom left and top right of an Ordnance Survey Landranger map (or maps, since multiple entries were allowed)? Was it just a pointless exercise to see if you knew your northings from your eastings?

No, it wasn't. Thanks to all the efforts of the competition entrants, our crags database will soon tell you not only where crags are (as it does already, with a map of the surrounding area) but also which of the 204 Landranger maps that crag is on.

That's useful because, let's face it, not many people take a laptop and mobile phone along with them to find a crag. If you've never been there before, what you want is a guidebook and a map, since it shows you where the paths go.

So what did the data you gave us do? Well, we already know where the crags are. And now with your help we've found out the bottom left and top right points of 91 Landranger maps. Because you're all climbers (we hope), the maps you entered also tended to be ones where climbing happens - hence lots of entries for the maps covering Sheffield and Snowdon.

What we found most remarkable though was the the prize for most-entered map for for No.203 - Land's End. Is Cornwall that popular? Or perhaps it's just that confusing.

"No, really, you drive"

We have to say that we're a bit worried about some of you - when you take us out to the crags you can drive, and we'll navigate, thanks, or you could all end up in the North Sea. People! There are instructions *on the map* for how to read it - see the little fold-out sheet on the right-hand side. It explicitly says, in a box entitled "How to give a Grid Reference (British National Grid)" that you "IGNORE the SMALLER figures of any grid number...." Their capitals. You generate a six-figure number for the bottom left of the map by looking on the bottom line of the map, taking the two big numbers in blue, adding a 0, and then doing the same for the left-hand side of the map.

So what did some people do? Yup, they included the smaller figures - and generated a six-figure reference that was completely wrong. In some cases this can lead you seriously astray - and get you very lost looking for a crag or other landmark. Quite a few people messed up this way. (Yes, Peter Bowen, and yes, David Burgess - even though you won eventually - that does mean you!)

You might be wondering how we knew that map entries were wrong if we didn't know what they were to begin with. Good question. The Landranger data follows a strict formula: the two-letter prefix for each grid reference covers a square 100km by 100km. When you come to the side of that square, you start a new two-letter prefix, for another 100km x 100km area. To the right of the SW box, which starts around Land's End, is the SX box, and to the right of that is the SY box... and so on in a strange patchwork (it turns into "N" first letter around the Lakes and carries on into Scotland, and a "T" first letter about halfway along the south coast). And we knew the pattern by which those letters change.

Some maps straddle letters (still with us?) but as long as you know the layout you can work out what is coming up. The difference between the top and bottom of the mpa. Since each map is 40km by 40km, and each of its 40 squares is 1km in size, a map whose bottom left-hand corner is SJ000000 will have a top right-hand corner of SJ400400. Simple as that. We only had to check to see that the difference between the corners followed that pattern - a number difference of 400 for each side. It got more complicated to make sure the letter prefix was right, but knowing the layout, we could.

The final rather useful thing is that quite a few Landranger maps are arranged in rows, or even squares, which abut each other perfectly. (Have a look at the Landranger page at maps 183, 184, 194 and 195 down by Southampton, for example.) If you know just one of those maps' values, then a bit of easy calculation will tell you all the others. So even though we only got 44 valid entries (from a total of 62, ie nearly one-third were wrong), we could work out the values for quite a few more maps.

And so that's it! Congratulations again to David. And thanks once more to everyone for entering. And if you have any of the maps listed below lying around and want to enter them, you can - but we're afraid we won't give you a prize. Just thanks.

Maps we'd still like details of:

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14
18, 19, 20, 21, 22, 23, 24
26, 27, 28, 29, 30, 31, 32
34, 35
39
42
47
49
52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64
66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84
87
93, 94, 95
100, 101, 102
105, 106, 107
112, 113, 114
121, 122, 123, 124
134
136, 137, 138, 139, 140, 141, 142, 143, 144
147, 148, 149, 150, 151, 152, 153, 154, 155
165, 166, 167, 168, 169
176, 177, 178, 179
182
189
193
197, 198