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.
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)