Re: GPS Vs COMPASS

On Wed, 27 Jul 2005 19:44:42 +0100, Roger <Roger@xxxxxxxxxxxxxxxxxxx>
wrote:

>The message <13bde19etrh7t5si6d899k52idiukjojmi@xxxxxxx>
>from Norman <nospam@xxxxxxxxxxx> contains these words:
>
>> I would think that in another 10 years no-one will be using the
>> magnetic compass and it will go the same way as the slide rule and
>> logarithms when the pocket calculator became available.
>
>Think again. If I am still walking in 10 years time I will still be
>using my compass to orient my map and to take bearings when it is not
>immediately obvious from the lie of the land which way to go. Why?
>Because I find it much simpler and much more flexible than faffing
>around with routes and waypoints for every possible eventuality. A GPS
>(I am on my second) is a wonderful instrument for showing where you have
>been and, in extremis, where you are, but they are a waste of effort for
>fair weather navigation and only of marginally greater assistance in the
>clag.
Clearly you must be using your GPS merely as an emergency device which
is a shame considering the cost and benefits it has to offer.

There is generally no need to bother with routes unless you want to
keep to a clearly defined path which in the UK is nearly always
visually discernable anyway.

My technique with a GPS is to mark the position of my intended
destination waypoint by saving the coordinates or transferring the
position via my PC. Then do the same for the start point, eg car in
car park at starting point at the beginning of a trek by pressing the
appropriate buttons. This can be done quickly either at home or when
you arrive at the start.
Normally, with a map, if you are walking up a hill etc it is usual to
start at the bottom and gradually follow the path to the summit
checking your route is correct by consulting your map in combination
with compass triangulation fixes with a compass and noting/comparing
localised terrain features with what you see around you and what is
printed on your map. Most of the time there is no need to even look at
a map because in clear visibility the route would be obvious by the
errosion caused by thousands of boots churning up the ground or
polishing the rock surfaces.

My method is to make use of all three ie map, compass and GPS
Using a GPS switch on and select find/goto the destination waypoint
and set off walking towards the destination by walking in the
direction the compass rose pointer indicates. If you want to use a
magnetic compass with the GPS you can set the GPS to give magnetic
variation compensated bearings and every now and then switch on your
GPS note the indicated bearing to destination and then transfer this
to your compass and use that bearing to steer with. Using this method
you can wander around exploring as you go. If you want to get back on
a path, find your position using the GPS, note coordinates, look at
map and locate present position and then work out bearing to nearest
point on path either by compass or entering coordinates of path
waypoint and getting the bearing to this new path waypoint from GPS
reading. Once on path put everything back in rucksack and plod up to
the top.

At top use car or start position as new destination and just do same
procedure as previous or follow path down hill.

Interestingly all ordnance survey maps are now corrected using GPS
derived coordinates. The triangulation points on hill tops serve as a
nostalgic reminder of the effort that went into producing the maps.

I look forward to the day when one can buy a device that you can put
in your pocket and when you want to know where you are you can just
ask it to tell you or show you on a 1 in 25000 colour map.

Norman

.