A lot of dyed-in-the-wool hill walking traditionalists pooh pooh GPS units. But do they really deserve this disdain or contempt? What can they offer hill

walkers? Are they worth considering? Read on and find out . . .

Bear in mind that you should always be prepared and capable of navigating without a GPS unit. GPS units are designed to augment other forms of navigation, not to replace them.

So what questions can a GPS answer and what features do they offer? Some you may know and some you may not. Well, here's the list:-

OK, that's the obvious one. Since GPS stands for global positioning system you could pretty much guess this one. But did you know that, as well as the default latitude and longtitude in degrees and minutes, you can also choose from many different positional formats including the one that is of most interest to us i.e. British Grid. Therefore, armed with an OS map of the area, you can read the grid cordinates from the unit and pinpoint your location on the map. Therefore, if you only use it for this purpose alone (and I know some who do) then it's worth its weight in gold for those occasions when navigation is difficult. I rate GPS units for this feature alone but they offer plenty more...

If you would like to record where you are for any reason, you can record your location and elevation as a waypoint and give it a name that you can refer back to later. This could be useful for recording where you've left the mountain bikes or, in emergencies, where you need to record an accident location.

You can see at a glance your elevation i.e. the measurement of height above sea level. So you should never be caught out again by false summits. Subtracting your elevation from the height of the peak you are tackling will tell you what ascent remains to achieve your objective.

A GPS unit can give you the times of sunrise and sunset at your present location. This is useful for planning your walk and ensuring that you can complete it in daylight.

A GPS unit can give you your heading - the direction you are travelling and your bearing i.e. the compass direction between your current location and your destination.

A GPS unit is usually equipped with a trip odometer which can tell you how far you have gone since the last trip reset.

If you forgot to check the time that you set out but you remembered to reset the trip odometer then the GPS unit can tell you the total time you have travelled since the last trip reset.

Like the speedometer in your car, the GPS unit can tell you how fast you are going regardless of whether or not you are on the right track. In addition, if you remembered to reset your trip when you set out, the GPS can also tell you your average and maximum speed since the last trip reset.

A track log feature leaves an electronic breadcrumb navigation trail which you can save for future use. When you are ready to return to where you started, the GPS will take you back along the track log that you left behind. Alternatively you can record your walk so that others may follow in your footsteps.

You can set up a route by defining it, in the GPS unit, as a series of waypoints. When you reach one waypoint, the GPS guides you to the next with a pointer and so on through each successive waypoint until you reach your final destination. This is extremely useful in bad weather when map and compass navigation is difficult.

The process of entering waypoints into a GPS is made made much easier if the GPS unit is used in conjunction with digital mapping software which is

the subject of another review article.

So, how do I rate gps units? Well, I wouldn't have one in my car but I'm a big fan of GPS units for hill walking. I always carry mine with me and on a number of occasions it has proved invaluable for identifying the current location and keeping on the right track.

Remember that, in the early 70's, according to Monty Python, a lot of people pooh poohed Australian table wine but now they can't get enough of them. Invest in a GPS - you'll find its worth every penny. I rate GPS units highly as an essential item of equipment for hill walking.