Scaling error in OSI Map "Killarney National Park"

Apparently an error has been identified with scalling on the 1:25,000 scale map.

I will link the post in mountainviews. But could have serious consequences. Not least because one does not need to miss the path to the east of the Devil's Punch Bowl and stroll over the edge into the Horse's Glen.

http://mountainviews.ie/motleyviews/general/comment/6147/

BarryD

I have a 1997 print of the OSI Killarney National Park' 1:25,000 scale map and it's fine - the kilometre grid measures 40mm x 40mm, so check your map before you start getting concerned! In any case, people should be navigating by terrain and contours in conjunction with distance measurements. One shouldn't ideally be in a situation where you relying totally on one form of positioning.

Chris O Donoghue

BarryD wrote: »

I have a 1997 print of the OSI Killarney National Park' 1:25,000 scale map and it's fine - the kilometre grid measures 40mm x 40mm, so check your map before you start getting concerned! In any case, people should be navigating by terrain and contours in conjunction with distance measurements. One shouldn't ideally be in a situation where you relying totally on one form of positioning.

The problem is with the most recent version of the map: I've seen both and the latest one is definitely wrong, so make sure you don't buy it. My buddy was recently on an ML assessment and spotted the error, as if the assessment wasn't tough enough. I think it's a very serious error given the terrain near Crohane, Mangerton, Dromderalough; tiny lakes, faint paths and seriously steep descents.

BarryD

Hmm.. it's a silly error perhaps but for your average hillwalker, not sure I'd call it a serious error. The error corresponds to 50metres in a kilometre - 5%.

I'd reckon there'd be very few people who could measure to a resolution of 50m in a Km or 5% of any distance using standard hillwalking methods of time / pacing on rough hill terrain. Put it this way, if you had to walk 500m over peat hags, gullies and rocky bits or whatever - you'd be doing amazingly well to measure that to 5% accuracy - 25 metres. GPS will resolve to about +/- 10 metres.

Trust me, I've done it!! Standard mapping tool over many years - good old compass & pacing.

dogmatix

I brought the OSI 1:25000 with me to Killarney back in 2009 and found it very poor. for example obvious trails up Torc mountain where not shown (but where shown on the OSI 1:50000 map!). I ended up using the far superior Harveys map on that trip.

It looks nice framed on a wall - but that's all it was good for.

Alun

I'm intrigued as to how this happened. If the whole printed map area is 5% smaller than it should be then the only two possibilities are that a different, non-standard, paper size was used, or there is an obvious margin around the edge of the map. I can't imagine either getting past even the most rudimentary quality control.

BarryD

Many printers work from .pdf files these days - direct to plate and then press. If I had to guess, I'd speculate that the printer accidentally reduced the file in the processing. Only alternative is that OSI generated the .pdf at the wrong scale?

As regards quality of detail on KNP map, sin scéal eile as they say.

Chris O Donoghue

dogmatix wrote: »

I brought the OSI 1:25000 with me to Killarney back in 2009 and found it very poor. for example obvious trails up Torc mountain where not shown (but where shown on the OSI 1:50000 map!). I ended up using the far superior Harveys map on that trip.

It looks nice framed on a wall - but that's all it was good for.

I had the same experience: we did a lot of day and night navigation in that area for the ML, and the 1:25 was useless. It's one of the few OSI maps to show crags but unfortunately they're often in the wrong places.

The Harvey's map is great, the different contour interval makes it slightly awkward, but it's certainly more useful than the 1:25, old or new versions.

Map withdrawn...

http://irishmountaineeringclub.org/index.php?option=com_loudmouth&task=topic&id=4443