Ramble On

Thursday, January 21, 2010

Tech Watch Geek: Baby Steps

Following up on my ill-fated trek to the Mary’s Rock trailhead a few weeks ago with my new Casio Pathfinder, I decided to take a short walk down the road from Hawksbill Cabin, taking some manual altitude readings at different waypoints. Before I turned back on the Mary’s Rock trail (you can read more at: http://hawksbillcabin.blogspot.com/2010/01/skyline-drive-misadventure.html), I thought I had taken three readings, but actually only recorded one. So this little trip was designed to get the hang of taking manual readings and reading back a record afterwards.

To do this, the watch has to be in manual mode – for the record, I am keeping it in this mode – and the readings are taken using button “E” which is marked with the legend “ALTI.” You simply press E until you hear a beep. These readings are stored in the watches memory, which can hold up to 50 records. Among the functions are records of the “min” and “max” readings, which contain the highest and lowest readings – when I am out on real trail hikes I will use this to measure absolute altitude gain.

The route from the Hawksbill Cabin to the Hawksbill Creek crossing is about 1.5 miles round trip, roughly measured using Google Earth. Along the way there are two hills and four stream crossings, including Hawksbill Creek. Three of the crossings are little Beaver Run tributaries that collect before their confluence with the main Hawksbill Creek.

So, my readings were taken at: (1) the cabin driveway; (2) at the first crossing of Beaver Run – the main stream that passes in front of the cabin; (3) at the top of the hill; (4) at the second crossing of another part of Beaver Run; (5) at the intersection of the road and the main road; (6) at the little red barn where I met my friends the donkey, horse and goats (there’s also a Beaver Run crossing here); (7) and at the end of my route, Hawksbill Creek at the big red barn.
As you walk this route, you get the impression that there are good altitude changes, due to the steepness of some of the grades. But the altitude change is really not very significant – at one point I started to worry that the changes wouldn’t be enough to even detect, since the barometric pressure readings are only sensitive enough to detect changes of 5 meters, or about 20 feet. That said, here are the records (taken in meters, I used a calculator (adjustment factor was 3.2 feet per meter, from an REI worksheet) to change them to feet):
I’ve got a few more things to learn about using the watch, including setting a baseline altitude so these readings more accurately reflect altitude above sea level (these records really only serve to define the relative altitude change between readings).
With the lowest reading of 190 meters/608 feet, and the highest at 220/704, the relative absolute change in this route is about 30/96. It was a fun learning experience – but I’ve got a lot more to go.
Also, a shout out to Bob at Old Rag Patrols blog - see the blog roll in the right hand column - for sharing his experience with his Garmin altimeter in some comments a couple of days ago - thanks Bob!

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