20-Jun-2000 -- It is 8.15am on a winter's day as close to the shortest
day that you can get and I should have been at work 15 minutes ago. But not
today -- hooky it is called. Taking a day off when you should be working. We
are in Markus's 4WD and we are heading to some place that has a mathematical
name S38 E176.
It is in the dark bush not too far from Rotorua, and some guy has put an
ice cream container there with some goodies in it. None of the goodies are
worth the effort that we will put into it. Andrew is muttering in the front
seat something about "should have spent more time learning how to use this
thing" as he furiously punches buttons on his Garmin GPS II+. There are a
whole lot of new words that I have not heard before -- waypoints, WGS84, and
others. Finally he seems happy and puts the thing down on the dashboard and
proudly says that we are 38km from our objective and that the bearing is
111° Great the technology might just allow us to make it.
As we motor forward at a steady 100km/hr the GPS seems to be pointing the
way and telling us that we are doing about 100km/hr. He must have set it up
right -- just maybe my earlier fears are unfounded? Just in case though I
have the ultimate weapon -- all of the maps of this area that one can buy,
and I can read them (I think)! After an hour of driving my trusty map tells
us that we must turn off this main road and head off into the wilderness.
The GPS seems to be saying the same thing and thinks that we have passed the
goal and that we are getting further from it. It is now only 5.5km away.
We follow some old forestry roads with expert guidance from map and
mapreader and soon come to a road end that is 1.6km from the goal. 9.45am
and we are off along the well formed bush track. The bush is too thick for
any satellites to be found except in a clearing on the way that shows we
have halved the distance in only 15 minutes. Hey this is easy. Another 15
minutes and we come to a lovely little lake in the bush - Lake Hiwiroa.
Also, this is the end of the track and we still have 300m at 239° magnetic
to go. We soon head off and find just how thick the bush is. Supplejack -
a half inch vine that can hold a man fast -- and it comes in thickets always
exactly where you need to go. So no coverage here from the satellite birds
above; we need to find a clearing. The first clearing is a failure - or is
it us? The second is a little better and we find that we are now only 110m
from the goal and at 240° magnetic. Hey we are holding our course well.
More floundering and we find a gulley clearing that must be marginal but hey
we get another fix -- 50m still 240° -- amazing. Even more floundering still
and we find a large windblown tree which I can climb up. I am momentarily
entrusted with the GPS and even I get a reading after a lot of arm waving.
The goal is now 10m at 20° or is it 20m at 40° away - we must be close.
"Hey Markus move away from me - right a bit - should be there".
"Whoopee there it is" he yells. We all gather around the small
white container with the GPS words on it. It is just sitting in the bush not
even hidden -- but who would come here?
So we made it after less than two hours much of which was waving that damn
GPS in the air. We are so pleased that it is nearly 20 minutes before we
bother to open up the container and fill in the book. It appears that we
are the first visitors since Peter McKellar located it here just over two
weeks ago. What a privilege, and what a nice place -- a very large tree just
to the North -- nice. We share a packet of chewing gum from the stash and
put in a pen and a choccie bar. Didn't really feel like taking much -- just
getting there was enough.
After nearly an hour at the site we decided to head off -- and that is where
the real fun begins. But first a little history. Andrew's GPS is a couple
of years old and was bought in the States. These two things mean that it
does not contain the NEW ZEALAND MAP GRID. Now this grid is unique to New
Zealand and is maybe 300m out from WGS84 which is used to define the
confluence points. So when you attempt to plot yourself on the map using
the rather inadequate latitude/longitude marks on the edge of the map you
put yourself where you are not. But it is hard to tell in the bush - one
bush looks like any other. Well add to this the inexperience of the team --
yes you guessed it we didn't put in a waypoint at the car. Really we felt
that we would not need GPS going back as we all had reasonable experience
finding our way around in this bush, but we did assume that we were in the bush
at the stash point co-ordinates that I marked on the map -- remember -- 300m out!
Also this is lowland bush with no major peaks poking out to guide us -- all just
low hills etc.
Well -- No probs -- just head East and we will hit the lake. Too late to read
the manual at this stage -- never did understand that trackback stuff anyway. Well
to confound things the true course back is 60° -- you know, complement of 240° --
hey we are engineers aren't we? and not 90° which is east. Add to that the fact
that we choose a few easy options to get around that damn supplejack and seems
that before long we are heading nearer to 135° (SE). Do your sums and we
are heading at about a right angle to the lake direction -- but no worries -- it is only
300m after all. We find the stream and yes it is heading south -- we are OK. But as
we head along the stream it swings around to the SW -- that is not right -- it doesn't
do that on the map? I wonder which planet we are on guys? Get another fix and
plot it on the map -- cunningly using the incorrectly located confluence point that I
plotted at home. Funny it is still telling us that we are where we are not. Hey guys,
it's getting late, the days are short, before long we might have to use that L word.
Didn't they say that even Daniel Boon used to get temporarily misplaced for a few
months at a time? Well we flounder around in this valley for a couple of hours trying
our hardest to make it run North South like the map says - damn thing seems to have
a mind of its own. We might just have to camp out soon guys. Finally Andrew,
muttering unnecessary apologies about learning how to use a GPS, makes a totally
irrational decision to march a compass course back along the line to the stash where
we left about three hours ago with about a 20° extra towards North (my cunning
innovation) to make sure we hit something we knew. We finally stumble onto the
track about 5 minutes from the lake and get to the bush edge at 5.10pm with dark
imminent.
Well in hind sight we all know a lot more about the GPS vagaries now. We
know that you need to set waypoints, what the different grids mean, and have
had some valuable experience marching in the bush with a compass. I think
we all benefited from the experience and agree that it would have been far
less fun if all this had not happened. Andrew now has the NZ map grid
downloaded and installed on his II+, I have a GPS of my own and we are
looking seriously at the other 11 confluence points in the North Island of
New Zealand.
A night out (considering our cumulative experience in the NZ bush) would
have been hard to explain to our friends and families, and even harder to
our colleagues back at work. And it was soooo close!
So if you tackle this confluence, make sure you have the right map (NZMS260,
sheet U15), a compass, AND the New Zealand Map Grid installed on your GPS!
A little knowledge of the NZ bush would also be useful - or not ;-).
Thanks Peter for a lovely Divine Stash point - we had fun - really