Paper maps can be way more than just a tool, taking on a personal significance. If you're a hill geek anything like us then you may have a particular favourite. For Nick Livesey it's a sheet covering some knobbly parts of Wales that the crowds rarely seem to reach...

OL18 Harlech, Porthmadog & Bala

It would be fair to say that I was a strange child; overly serious, pedantic and often lost in a world of my own indulging in one of my 'special interests'. One such interest was maps, be they A-Z sheets of my home town, an atlas of the world or, my constant companion, a 1975 edition of the Reader's Digest AA Book of the Road. I would spend hours tracing routes across the length and breadth of the British Isles, visiting exotic sounding locales like Leighton Buzzard and Goole as I journeyed through the pages.

My grandfather, a well travelled, leather-gloved 'Motorist' rather than a mere car owner, would conjure up the most obscure place names he could think of and I would flick through the index and then find them on the map. For a 10 year old lad in the early 80s, this was a thrilling exercise. Forty years later, I still love my maps. They fill several shelves, adorn my walls and have become an essential tool for both work and play. Never wanting to be outdone I also happen to live slap bang in the middle of the Ordnance Survey's best selling map, OL17.

Never before had I experienced such a profound emotional response to a landscape. That was the moment OL18 became my favourite map, and it has remained so ever since

For many years, OL17, the big scale map of northern Eryri, was all I needed to satisfy my desire for adventure. Indeed, for the hillwalker, scrambler and climber, this map contains an embarrassment of riches and there are those who never manage to escape onto neighbouring sheets. Nevertheless, as the time passed, the draw of steep places began to fade in direct proportion to my growing preference for exploration and quietude. It was time to head south and see what OL18 could offer.

My first foray onto OL18 came after I developed a peculiar obsession with Arenig Fawr and, after an acrimonious disagreement with my then partner one afternoon, I drove to Wales to climb the mountain, telling her that I would spend a few days with a local friend until the dust settled. At the time, I thought I knew Snowdonia well; I didn't. Bookended between the Snowdon massif and Cadair Idris, I discovered a huge area which for me was terra incognita, hosting 37 2000ft peaks which I had yet to visit.

That first day, as I drove through Llidiardau I realised that I had come upon somewhere very different. Back on OL17, the peaks are tightly packed, the valleys cramped and claustrophobic. On Arenig Fawr's summit, however, there was space and the feeling of a wilder landscape which would take time to get to know in any meaningful way. The great peaks of the north were strung out before me and I could name them all, but as I turned my back on them I didn't recognise a single mountain.

My next visit to Wales sowed the seeds of a long standing love affair. I had responded to my latest obsession and found myself beside Llyn Hywel in the heart of the Rhinogydd before climbing onto Y Llethr. By then I had bagged almost 100 Wainwrights, climbed some of Scotland's finest mountains and, of course, had become very familiar with OL17, but as the sun began to set with Rhinog Fach, incandescent in golden hour light, I was befuddled. Never before had I experienced such a profound emotional response to a landscape. That was the moment OL18 became my favourite map, and it has remained so ever since.

A couple of weeks later I found myself living in a caravan in Prenteg near Tremadog and the first hill I climbed, as it happened to be on my doorstep, was the unprepossessing Moel Ddu. It was another one of those moments; OL18 had done it again!

The intervening years have found me filling in the gaps of OL17 and getting to know OL23, leaving me with a strong conviction that, along with OL18, I need never buy another map in order to find new and beautiful scenes to enjoy. Of course I will though, who ever heard of anything more ridiculous than having too many maps?