About GPS Units

GPS or ‘Global Positioning System’ devices are units that provide accurate location and time data anywhere on the Earth so long as the unit has access to 4 or more satellites via an unobstructed line of sight. Like many great consumer devices, such as the telephone, the Global Positioning System was originally invented by the army. There are currently 30 healthy satellites in orbit that are available for use by civilian GPS systems, and in most places on the Earth anywhere between 6 to 11 of these satellites can be seen at any one time, making the failure of a device due to no access to a satellite extremely unlikely. The secret behind the technology is that the device is constantly sending and receiving data from satellites diploid in geo stationary orbit. This data is then processed by the processor (via a special software) to calculate positions to within 10 metres approximately. This makes them one of the greatest inventions travellers are proud to have. No matter where you are, whether you are in the heart of a super city, like London, or in a vast desert, like the Sahara, the GPS will guide you through 24 hours a day. Most consumer units now incorporate a whole host of features useful whilst travelling such as:

• Moving colour maps
• Digital compass
• Speed of travel
• Altitude
• Time of arrival
• Multiple waypoints (specific locations)
• Time

Even though GPS systems are now most commonly thought of in the form of a car Sat-Nav, the technology is increasingly being built into more and more everyday electronic devices, including mobile phones, laptops, palmtops, and watches. One of the most useful GPS devices to a traveller is a dedicated handheld GPS. There are many different units on the market to choose from, all with different features and great differences in terms of performance and price.

Types of Handheld GPS Units

Basic:

What are the different types of handheld GPS devices?
There are basic units which do exactly what the name implies: providing the user with very basic functionality such as displaying latitude and longitude or a map grid reference, and the time. They also display basic route information and any waypoints you have passed. These units usually still have to be used with a conventional paper map and a compass for effective navigation. But if you are comfortable with having to make this compromise then the lower price in comparison to the more advanced units can be tempting. Overall basic GPS devices are usually the most affordable way of incorporating GPS navigation into your box of travelling tools. But their lack of maps and limited functionality has rendered them almost obsolete in recent years, with much more advanced mapping units becoming much better value and more common. So unless you are absolutely certain about choosing a basic GPS unit you would probably appreciate the features of a mapping unit much more, albeit at a higher price.

Mapping:

What are mapping GPS units?
Mapping GPS units display graphical maps on their screen as well as incorporate a digital compass, in addition to providing the user with the basic latitudinal and longitudinal data. This saves having to carry paper maps around and they are also extremely easy to use. They show on the display exactly where you are, which way you are facing and where (if you have planned) the next part of your route is. Many mapping compasses also include a lot of the aforementioned useful features. This extra functionality does however mean an increase in price from the basic units. It is important to consider when choosing a GPS system that it would be unwise to go for the cheapest possible option. It would be unwise to spend far too much money on a top of the range unit if you are not going to use all of the extra features to their full potential.

Radio:

What are radio GPS units?
Radio Unites are the third main type of unites, which can be considered as an extension of the basic and mapping units. They range from basic to full mapping specifications in terms of features, and they also serve as two-way radio systems. These units would be extremely useful to anybody travelling in a group where separate individuals would be in possession of their own unit. Particularly if at any point some members of the group either split up intentionally or perhaps get lost. The added radio functionality may provide a sole means of contact when there is no other way of communicating mid to long distance with people you are travelling with, especially in the desert. This communication aspect linked with conventional GPS functionality would make finding a lost travel associate very easy.

Basic GPS Devices

Garmin eTrex® H:

The Garmin eTrex H is an affordable entry level point-to-point GPS device that when combined with the use of paper maps can provide an efficient navigational tool. It has seen an important improvement over the earlier eTrex model in that the new ‘H’ model has a new higher sensitivity receiving aerial. This drastically improves satellite lock, ensuring you do not lose your position when in an area where the sky is partially covered. It also improves the overall accuracy of the device from 15m to 10m. Internet prices range anywhere from £59 - £109.

Magellan Sportrak:

The Magellan SporTrak is medium in size compared to some other GPS receivers and is not too heavy. The fact that it is nice and lightweight, as well as the fact that the buttons are easy to access, makes it ideal for comfortable one-handed use. When tested in forest cover in close vicinity to large cliffs, the SporTrak held its signal with at least medium signal strength and locked on to more than the required amount of satellites at all times. It should be again noted that this is not a mapping GPS receiver and provides only basic functionality, however it’s a good value unit for a first time user that may not require a more sophisticated unit.

Garmin Forerunner 310XT GPS Watch:

This basic GPS unit has been incorporated into a watch and is aimed at climbers and athletes. It still functions as a GPS receiver, providing latitude and longitude readings wherever you are. But it also includes features such as a heart rate monitor and calorie counter.  The Forerunner GPS watch is a fantastic example of GPS technology being incorporated into other everyday technological items. And even if you are not a climber or an athlete whom this would suit ideally, at least you could be sure you would never find yourself having forgotten your precious GPS. Amazon prices start at £213 and the RRP is £310.

Top Mapping GPS Devices

There are hundreds upon hundreds of mapping GPS units on the market.  The following are only a small selection of the top brands  in terms of specifications and customer reviews.

Garmin GPS 60CSx:

The Garmin GPS 60CSx is the first handheld GPS by Garmin to feature a removable memory card. This stands for almost unlimited map capacity and the ability to carry hundreds or even thousands of different maps around in your pocket. The tracking of this unit is extremely precise and it locks on to a satellite blisteringly fast. It is a very high quality unit from one of the most respected manufacturers and is definitely one of the best value for money units considering its features. Its high reputation with all kinds of users has raised it to the status of gold standard amongst handheld GPS units, and it is still the benchmark device many others are compared to. Amazon prices start at £209 and the RRP is £339.

Delorme Earthmate PN-60:

The Delorme Earthmate PN-60 is one of the higher end units and its wealth of features make it a popular choice amongst hikers and travellers. It is renowned for incredible accuracy and strong satellite lock in almost any conditions. The Digital compass is also one of the best, featured on any handheld GPS. Also the computing power this little device possesses is astounding. This of course makes using the device extremely easy and it will not lag behind when dealing with a complex map display or re-draw. All in all the PN-60 is a very powerful, very efficient handheld GPS unit, and one well worth looking at.  

Garmin Oregon® 550t

The Garmin Oregon 550t is Garmin’s top of the range touchscreen handheld GPS, and is widely regarded as one of the best overall devices on the market. It has all the many features to be expected of a top of the range GPS, although it does not become incredibly hard to use them due to fumbling with a hundred different buttons, because there are not any. Aside from the power button, the Oregon 550t is entirely operated by the touchscreen display making this remarkably user friendly. If you are looking for a top of the range device with every feature packed in, (including a 3.2 megapixel camera!) and you also want a device that is very easy to use then the Garmin Oregon 550t is the device you may want to  consider. Amazon prices start at £340 and the RRP is £489.

Magellan eXplorist 710:

A strong competitor in the market to the Garmin Oregon series is the Magellan eXplorist series. These rugged little GPS units are tough and waterproof and also feature a camera. They do however also feature a few programmable buttons as opposed to the Oregon’s entirely touchscreen based input. In terms of specification both the eXplorist and Oregon series models are almost identical which leaves it up to personal preference. This is where it would be advisable to try both units out to see which of the different manufacturers menu systems you prefer. Another factor that will help choose between the two however is the price: $549 or £350 approximately.

Garmin GPSMAP 62st:

The Garmin GPSMAP 62st is an updated model version of the GPS 60CSx mentioned earlier, with which it shares a number of similarities. Now the 62 series include some of the best handheld GPS units available. If you are considering the60CSx even though it is an old model you may want to consider the new features that have been added to this model: BirdsEye aerial imagery, custom maps, advanced track navigation, and paperless geocaching. The accuracy of the new models is extremely close to that of the 60CSx and the extra price is well worth the extra features for a rugged, robust, high performance GPS unit that is the successor to one of the most highly regarded handheld GPS’ ever. Amazon prices start at £309 and the RRP is £399. The mapping devices mentioned here, it is worth noting, all come from ranges that include similar, but cheaper models. It is probably therefore worth checking out corresponding models to the very best mentioned here, to see if you can find a cheaper model that does away with some features you can live quite happily without.

GPS Resources:

A simple guide to using GPS, a Compass and map:

A short guide to navigation relevant to driving off road, using the simple compass and GPS.
Read More (http://www.tobysavage.co.uk/showarticle.asp?id=5).

Free GPS Maps:

Free GPS Maps (http://www.maps-gps-info.com/free-gps-maps.html), Info & links.
Also a long list of free GPS software for your computer and mobile devices.

Convert Coordinates to GPS Points:

Convert Coordinates to GPS Points: (http://boulter.com/gps/) convert and map coordinates to GPS points (I have noticed the position mapped after entering the coordinates in this tool is about 1000 yards away from the coordinate position on the original Google map).

Waypoints:

The International GPS Global Positioning System Waypoint Registry: (http://www.waypoint.org/)
building a world wide database of GPS coordinates.

Convert Google Maps Data to GPX

GMapToGPX: this tools extracts data from Google Maps and converts it to GPX format suitable for loading on a GPS. It can create a GPX file based on driving directions, an address search or a local search.

The instruction are pretty simple: go to the website (elsewhere.org/journal/gmaptogpx/), drag the link to your browser’s bookmark toolbar, go to Google maps and get some search results of your choice, then click on the GMapToGPX bookmark in your toolbar to display a GPX file over the Google map. Now you are ready to copy and paste the code into a text file and save to your desktop with the extension “.gpx” or “.txt”, and then load the GPX file into your GPS or mapping software.

The Lonelyplanet's guide to Libya lists a number of GPS locations of prehistoric paintings and drawings in Acacus, including:

Adadh (N 25 31 18.77 E 10 35 58.70)
Acacus (N 25 20 00.49 E 10 31 19.52)
Acacus: Three Women Dancing: (N 24 42 03.51 E10 37 08.83)
Acacus: Wadi Anshal: Women: (N 24 43 27.49 E 10 31 52.66)
Acacus: Wadi Anshal: Elephant & Giraffe carvings: (N 24 43 34.84 E 10 33 11.44)
Tashwinat: Wan Targhit: Hunting Scene (N 24 51 21.52 E 10 32 25.09)
Ancient rock-carved map of Wadi Tashwinat: (N 24 51 07.58 E 10 31 09.16)
Wedding Scene: (N 24 50 25.89 E 10 30 09.35)
Tin Khilqa Rock Arch: (N 24 51 24.45 E 10 34 41.12)
Awiss: Elephants: (N 25 19 37.16 E 10 32 25.03)
Awiss: Human Figures: (N 25 19 32.64 E 10 32 16.22)
Awiss: Wadi Udhohen: Chariots: (N 25 17 12.88 E 10 34 53.12)
Awiss: Wadi Tiheden: Fighting scene: (N 25 16 01.25 E 10 35 45.13)

Map Centre Two:

Mapcenter2 (http://mapcenter2.cgpsmapper.com/) was created to share maps for Garmin GPS receivers and find maps created by GPS enthusiasts from all over the world. They are amateur map authors and have created this service to promote their work and the work of other free maps authors. (http://mapcenter.cgpsmapper.com/maplist.php): (Roads, Cities, River, some POI; Free VMAP0,1 and ESRI data; build contains self install for MapSource (ID 2446)).

Tunisia V11 (http://gps.4x4travel.org/)

Download Tunisia vector map for Garmin and compatible devices: showing only dirt roads and paved roads (no off road tracks) in Tunisia, with waypoints:cities, villages, hotels, restaurants, fuel stops, car services and Tunisian sahara wells.

Tracks4Africa:

Tracks4Africa (http://www.tracks4africa.co.za/) is a non-profit organisation run by ‘Environmental users’ with the aim of mapping Africa accurately, reliably and environmentally. Their main focus is the GPS mapping of all the eco-destinations in rural and remote Africa. Their tracks are now in Google Earth: see Layers >More.