GPS Co-ordinates
The most important advice is to study the manual of the GPS receiver.
GPS is the abbreviation for "Global Positioning System", that is, the
global fixing of a location. The system was originally developed by the
American Defence Ministry for military purposes for fixing a position.
It consists of a network of 24 satellites, which circle the earth twice
a day at a height of 20,000 km. These satellites transmit their track
data and the exact time of day everywhere on earth. The information is
(at the moment) received free by every GPS receiver.
Accuracy and equipment.
Until 2000 accuracy was intentionally lowered to 50 to 100 metres.
Today, the accuracy of GPS position fixing is ideally 3 to 5 metres.
The GPS units operate - still with restrictions - even in the densest
forest, in cramped urban jungles or in the car without external
antennae. In addition, it's possible to store Waypoints and Tracks on
all (or at least the newer) units. Furthermore, there is a so-called
GOTO function (direction and distance to the entered destination),
likewise the altitude above sea-level is shown. It also gives current
speed, average speed, remaining time until arrival at the destination.
The interfaces require care - not all instruments have an interface for
the transfer of data between the PC and the GPS (and vice versa). Also
take care that the selected route programme on the PC supports the
selected GPS instrument.
Position fixing
Fixing a location with the GPS is in itself very easy - after switching
the instrument on, you very quickly receive the co-ordinates of the
viewpoint currently displayed and can store these. To merely find your
way to known points (e.g. to find the location of your car again after
a walk) you will need nothing more than the GPS receiver. Mostly,
however, you will want to have the route shown to a specific place or
you will want to connect the displayed co-ordinates of the current
position with a point on the map.
Units with built-in maps
Today most GPS units have "built-in- maps", ie. you see the miniature
edition of a topographical map on the display. Limited by the size of
the display, the map section shown is relatively small. The built-in
map material is usually relatively approximate and is limited to roads.
Detailed maps can, however, be reloaded in the better instruments , as
can also the 1:50'000 maps from
www.swisstopo.ch
Advantages of navigation with GPS
* A route which has been fixed or transferred in advance can show the
route during travel, whilst this route is compared with the current
position.
* After a tour the results recorded by the GPS can be transferred back
to the corresponding programmes; you can then see everywhere you've
been&
Restrictions and limits
* GPS as a compass - it's not possible to obtain reliable data about
the (compass) direction when not moving, but only when movement between
two points begins. The reason being that in contrast to a compass the
GPS does not ascertain the (compass) direction by means of magnetism,
but always from a difference of position between two points.
* Possible shading (dense forest, narrow gorges, between buildings) makes the fixing of the position more difficult.
* Other risks: the instruments can have technical failure, batteries
are empty, damages, loss, mistakes in operating the machine.
* Therefore - don't rely only on the GPS - the GPS shows exactly where
you have gone wrong, but you must find out why yourself. Take a map,
therefore, and, if need be, a compass, with you. Never go on remote
stretches alone, even with GPS!
* And in general - common sense should always have the upper hand. So
don't cross the river at the most torrential point, because the GPS
orders you to do so, but use the bridge 50 metres further on the right.
What's needed for equipment and software?
* The download of MySwitzerland-Routen is nothing else than the listing
of the x/y co-ordinates of numerous waypoints; together they form a
route.
* This document (Routes file) can be loaded onto a PC/Mac, the GPS unit
or a PDA. What the unit does in practice with the waypoints is
dependent on the map software downloaded on it.
* Digital map material is not delivered with the Routes file of
MySwitzerland. Computer, GPS or PDA show the route on any stored maps
(e.g.
swisstopo.ch).
Download of the routes from MySwitzerland.com
* It's possible to transfer a Routes file directly via a PC to a connected-up Garmin unit.
* The document can, however, first of all be downloaded to the PC or
Mac, before it is transferred to the GPS. A small piece of software is
necessary for this, which can be obtained free of charge.
* For transfer to a Map-Processing-Programme, such as the TTQV3 (PC only) from
touratech.de, it is best to use the pure txt document.
(Certain statements of these explanations come partly from www.suess-web.de)
Hiking 
