Wednesday, June 25, 2014

Navigation - how do you find where you're going when you're out with your camera?

What kind of phone do you have and what do you use it for? My best guess is that like a lot of people you use a smartphone but never actually use it as a smartphone.

I'll admit - I use a smartphone because I'm forever forgetting to write down addresses - which I can look up on my smartphone. I also use it for navigation because though I have a GPS unit, it is rather elderly and a bit temperamental. It's an old TomTom One that was purchased some 8 years ago. It does work when it eventually locks onto a satellite though that can take between 2 and 30 minutes. During the winter, it seems to lose its voice directions which is interesting. Hence, of course, the GPS in a smartphone comes in very handy - especially since the maps are constantly updated.

Time was when everybody used a map and a compass for navigation. Most cars these days come with built-in compasses which are largely now a novelty than a useful feature since the advent of GPS systems. It's still worth carrying alternative modes of navigation however. Satellites etc are not all that reliable. They're good but it takes only one solar flare to knock them out for a few hours.

As many of you know, I don't pay much for my cellphones. I can't afford to. Thus I do encounter areas where there is little to no cellphone reception. In these areas, cellphone GPS just does not work. The elderly GPS that I put on the dashboard when needed does work but requires constant powering since the units batteries failed many moons ago. Off the track though and on foot in these areas, I rely upon my oldest GPS unit. This is about 9 years old and takes a couple of minutes to lock onto the satellites and runs for about 3 hours on a pair of AA batteries. Needless to say this is used solely when I head off the track on foot. It would be nice to update the maps but the software uses a version of OSX even older than my laptop and a 9 pin D connector that is never now seen on computers.

Some while ago there was a news story about a taxi driver that spent two days lost in a swamp with his children. They'd wandered off the beaten track. They were found after a day of searching by a large team of Park Rangers only about a mile from the visitor center. Had they had one of these units, they could have backtracked along the path they had already taken or taken a short route to the exit and not been lost for days.
How do you navigate? If you follow my route of having several backup systems then you'll never get lost. Maybe there's something more modern that'll do it all for you - I don't know. I can't afford new stuff so I just don't look.

Now to the main point... How in tarnation do you use a map and compass? It's actually not that hard:

  • Step away from all possible sources of magnetism. The earth's magnetic field fluctuates and can be weaker in some areas than others. Thus, step at least 20 feet away from a vehicle. Put down any guns or metal walking sticks etc and walk away from them too. Avoid all sources of magnetism.
  • Lay the map out flat and put your compass on the ground flat.
  • Turn the map so that the top of the map (often marked N) is lined up with the North point of the compass. The purist might like to turn the map a couple of degrees because magnetic North is slightly different from true North but for short distance navigation like most people do, there's no real worth to it.
  • Look at the features marked on the map such as hills and valleys and see what's around you. That should pinpoint your location fairly readily. It's very rare that you'll be in a landscape without features.
  • In a featureless landscape or seascape, it's normal to use a sextant, a compass and a clock for precise positioning. That's for another article though.
  • Looking at a worst case scenario - your plane crashed in a desert and nobody knows you're lost. Aside from simple survival strategies, if it's necessary to walk out then walk either North or South since most deserts are wider from East to West than they are from North to South. 
The good thing about maps and compasses is they are cheap and lightweight as well as needing no power source other than sunlight or lamplight. 

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