The Ordnance Survey regularly updated its maps to reflect features like new roads and housing developments.
But few of these occur in National Parks, and maps bought by walkers decades ago are still very reliable guides to some of the region’s best-loved areas including the Yorkshire Dales and North York Moors.
Recently, though, there has been a small yet significant change to one of my most-used maps, the OL2 Explorer sheet covering the Yorkshire Dales Southern and Western areas on a scale of 1:25,000.
First bought in the 1990s, it now bears the scars of many an outing, not least a lengthy tear down the fold running parallel to Ribblesdale and a large brown coffee stain resulting from some long-ago gust of wind.
On the east side of the rip the height of one of the Three Peaks, Pen-y-ghent, is given as 694 metres, or 2,277 feet in old money, while some distance to the west, the summit of a much-less climbed fell called Calf Top is put at 609 metres.
However, while the latest OS map leaves Pen-y-ghent and every other fell in the Yorkshire Dales at exactly the same height as before, Calf Top has managed to grow an extra metre.
How did this happen?
As far as I know there has been no volcanic convulsion or glacial action to alter the area’s topography.
So perhaps the answer is that officials at the Ordnance Survey simply conducted a new survey of Calf Top.
Which is what happened, of course, with the outcome being that their new summit measurement clocked in at 609.606 metres.
In accordance with the OS’s usual practice, the figure was rounded up to a full 610 metres.
What gives this change special significance is that - as readers with rapid calculator-like minds may have spotted - it takes Calf Top fractionally over the 2,000ft mark.
And that means it is officially classified as a “mountain”.
Calf Top sprawls along one side of the Lune valley and became part of the Yorkshire Dales National Park in 2016 when the boundaries were extended to the west and north-west of those laid which had been down back in 1954.
So when I learned that Calf Top had gone up in the world, as it were, it was hard to resist the desire to stand on the summit of the newest mountain in the Dales.
A very impressive place it is too, thanks to the impressive view of nearby Whernside, at 2,414 feet - 736 metres - Yorkshire’s highest peak, and a breathtaking panorama to the west that includes Morecambe Bay and the Lake District fells.
But Calf Top is exciting in its own right, the climb up its southern ridge from Eskholme Pike being as good as anything in the Dales.
And on one side of the summit plateau stands perhaps the most magnificent stone cairn in the entire national park, an eight-foot monument with no real purpose as far as anyone knows.
Long overlooked by walkers, I have a feeling that Calf Top will become a popular climb.