Spot-heighting

I number of my earlier posts refer to spot-heighting - this refers to planning trips to visit the heights that are marked on the standard Topo 50 tramping map.  It's a bit of an odd pursuit so it justifies a bit of explanation.  It might be useful checking out the topo map should you feel the need to visualise what I'm banging on about.

Pt 953 in the above image was the final spot height  that I visited in the Tararua Range. 

Pre-Ramble

Humans are acquisitive by nature. Whether it's match boxes, money, flash cars, or locomotive numbers - you'll find someone that is intent on collecting the box set.

There are generally 'rules of the game', some codified in writing, others are more convention in nature.  And, of course people will exhibit different levels of commitment, from the social book collector to the militant geocacher.

In tramping circles the hut bagger is a well-known, and relatively socially acceptable example of the breed. Others will tick off tracks, peaks, or great walks. The one we're dealing with here is at the somewhat obsessive end of the spectrum - the spot-height bagger - those intent on visiting all the labelled heights in an area.

Why spot-height?

It is a natural tendency to seek out new tramping experiences - to walk a new track or climb a new peak. Inevitably, this leads to sorties off the marked tracks.  At some point, perusing the map for interesting streams and spurs, you note that your wanderings happen to have traversed all but one of the spot-heights in an area. The observation becomes an idea, which becomes an itch, and the itch becomes ... well, obsession is probably a little strong a term. 

Another 'why' that might have a little more resonance is that in pursuit of an isolated spot you will inevitably find yourself in a place that would not otherwise have caught your eye. I can think of many examples where I have unexpectedly dropped into a pretty stream valley or stumbled on a rocky outcrop with panoramic views. (It would be impolite to chip in at this point and inquire about the other inevitable experiences involving bluffs, swamps, kiekie, supplejack, and ongaonga.)

A variant of this last benefit is that designing a route to efficiently pick up a selection of spot-heights can create an unexpectedly delightful trip. Again, I can think of many examples but one of the more pleasurable was a mid-range crossing from Otaki Forks to Holdsworth via Kahiwiroa.

If these reasons are not enough, the process of navigating through clag and beneath high canopy forest to points that are sometimes pretty indistinguishable, will improve your bushcraft and navigation skills.

And finally, the physical challenge is almost reason enough. Dropping from Mt Holdsworth into Francis Creek in order to climb to spot 1120 provided all the pleasures and benefits outlined above, as well as a sense of achievement and the health benefits of working off at least half the pies eaten in the preceding week.

Having post-justified this rare affliction, I will take the liberty of defining my own collection rules -  more like guidelines really.  On the way I'll throw in a few explanations - what spot-heights are, which are in scope (and out), and when can one be considered to have been 'bagged.'

What are spot-heights?

A spot height is a dot on a map with a number next to it giving the altitude of that geographic location. For my purposes the map in question is the current version of the LINZ topo 50 maps - these are the standard tramping map with a scale of 1:50,000. I.e. each two centimeter grid line on the map represents a kilometer of terrain.

You'll find spot heights at obvious features such as the top of peaks and knobs - but others just seem to be scattered haphazardly across the landscape. So what are they for?

Best I can tell, they were determined when they created the contour lines on the map. This was initially done in the good old days - before the government flogged off the family silver.  A bunch of earnest types in the bowels of the Department of Lands and Survey Information would stick two overlapping aerial photos into a special machine. This would feed slightly offset images of the ground to two eye pieces - the brain of the observer looking through them would be fooled into seeing a three dimensional image of the terrain. 

To cut a long story short (and avoid revealing the depths of my ignorance), the machine would be focused in at different heights and lines drawn by hand to delineate the terrain at set contour intervals.  The spot heights were determined during this process - and if the machine was focused at a height in the middle of a featureless river flat (I'm talking about you, pt 332 in the Tauherenikau Valley) then that's where the spot height would be recorded.

Which spot-heights should be bagged? Just as a philatelist my elect to confine her interest to 19th century Finland and spurn pre-1895 imperforate Danish offerings, I have no particular interest in spot-heights outside the Tararuas. Which raises the question; what are the boundaries of the Tararuas? 

There's a lot of private land, reserves, stewardship land, and other esoteric land categories that are encompassed by what is collectively referred to as the Tararuas.  So, to keep things manageable I decided to confine my collection to spot-heights within the boundaries of what is legally defined as the Tararua Forest Park. It is a complex shape but LINZ has downloadable files that define it precisely (at least I assume they are precise).

Inevitably, you end up wandering over spot-heights on those other land categories - but for my purposes they're not 'in scope' (this is completely uninfluenced by the tendency for those places to be covered in scrub).

As to how many there are in the Tararua Forest Park.  I'd be happy for someone to volunteer to find the park boundary shape file and superimpose it on the right topo map overlays to create a definitive list - however, my rough count came up with 650 (ish).

When can a spot-height be considered to have been bagged?

Many spot-heights relate to features where there is no doubt when you have arrived, such as a peak or knob. With others, you know you have been there because they are bang on a linear feature such as a track or spur that you've traversed. Yet others may be on a broad ridge top, a river flat or otherwise indistinguishable from the surrounding area. 

Tricky to be exact

It's a bit of a cliché, but it is about the journey not the destination. I.e. provided I've clearly got to the immediate locale of a spot-height and there is no barrier to actually standing on it, I'm not bugged about locating the precise spot. In practice, this means that I don't bother with a GPS but am satisfied that I have navigated to the spot by map, compass and sometimes altimeter.

By way of example, traveling the old Waiotauru Road from the top of the Akatarawa Road to Maymorn Junction, there are five spot-heights that are quite close to the road. These are inside the park boundaries and, in my view, sufficiently far from the road to require some effort to get to them - most having at least one intervening contour line. These therefore required deviations from the road to knock them off (and what a pain it was). Conversely, pt 735 is not on the Roaring Stag track but is as near as damn it and, to mind, it would be pointlessly pedantic to insist on deviating in order to stand on it.

So there you go. I don't recommend it - far better to let someone else thrash about in trackless swamps and pursue nondescript points on unremarkable spurs. Just listen carefully and go directly to the occasional gem that they find and save yourself all the aggravation.