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GPS navigation is very well suited for bushwalking in the Perth region of Western Australia.   Due to the relatively light or open eucalypt forest conditions and mainly gentle terrain in this region the GPS unit is able to maintain good satellite coverage and tracking in almost all areas, with the result that good navigation accuracy should be achieved.  Location accuracy is often as good as 5 metres. 

Modern GPS units can generally maintain accurate position fixes even under denser tree canopy.   In my experience (using Garmin's basic eTrex unit) misleading readings have been rare, as verified by directly comparing downloads of the actual 'tracks' (recorded while walking) with the intended routes.  Misleading readings could occur however on steep hillsides  (due to signal reflections) and reduced accuracy will occur if less than 4 satellites are in view of the receiver or if they are all in line or in a tight grouping. Those situations are unusual however and the receiver will indicate if the signal is weak and navigation accuracy is poor.  Clouds and weather conditions do NOT significantly affect accuracy.

Commonsense dictates that we should always have a map and magnetic compass with us when going off-track bushwalking and know how to use both.  The map should be used in conjunction with your GPS.  You should have at least sufficient map-reading skills to know where you are on the map and in relation to the surrounding terrain.  Knowing where you are on the map also allows greater flexibility to vary the route away from a straight line to the next waypoint (e.g. to avoid thick scrub or to visit features of interest seen off the direct line while walking). Although you must also always have a magnetic compass with you, in this region it is really a matter of personal preference as to whether you use it routinely in conjunction with the GPS or as back-up in an emergency (e.g. in the event of misleading or confusing GPS signals, flat batteries and no spares, or if  the GPS unit gets damaged or lost).

Personally I prefer to keep the compass as emergency back-up only;  I find that using the GPS direction pointer arrow on its own (in 'Go To' mode) is easier and quite sufficient.  However, if you are to rely mainly on the GPS in this way you need to be aware that you have to be moving for the GPS pointer arrow to correctly point toward the destination. Generally you will probably know from your map and surroundings the approximate direction to start walking in. After only a few walking paces the  GPS direction arrow should indicate the correct direction to the destination waypoint. While continuing to  walk you can then readily make any necessary adjustment to your walking direction.  If you have no idea which direction to start walking in, simply move off in any direction and then similarly make the direction adjustment so that your walking direction matches the direction indicated by the pointer arrow.

However, if you still prefer to use a magnetic compass to get started and to check your direction, then you can obtain from the GPS data display the bearing from your current location to the destination waypoint. Transfer this bearing to your compass and then use the compass to establish your walking direction in the traditional way. One advantage of using a compass routinely between waypoints is that it will save on batteries which could be a key consideration on longer walks.  A disadvantage is that using the compass encourages less interesting  'straight-line' walking between waypoints and detracts from the great flexibility that the GPS offers to vary the route away from a straight line and still find the destination.

Whichever navigation style you adopt, never forget that the basic GPS unit is NOT a compass. i.e. The GPS direction pointer arrow does NOT show you which way to move while you are standing still. (Also see 'Before starting to walk' below).

If you have a scanner and one of the GPS mapping software packages you will be able to quickly create your own walk routes and maps in six or seven simple steps as follows (OR in place of Step 1 & possibly Step 2 you can use map images already available for the region on DVD or CD):

1. Create a Map Image file (e.g. .bmp, .jpg, .png) by scanning the portion of an existing map which covers the area of your planned walk. 

2. Calibrate the Map Image to the known Grid Coordinates using GPS mapping software (e.g. GARtrip, GPSUtility, OziExplorer -see External GPS links). Ensure you set the correct Map Datum and Projection.

3. Set Waypoints on the Calibrated Map at locations you may wish to include on your chosen Route. This creates a Waypoint Listing. Alternatively, you can import waypoints from existing listings such as provided on each walk page of WalkGPS. -The free, downloadable WalkGPS waypoint listings are in the form of (zipped) plain text files in Garmin PCX5 format, WGS84 datum and decimal Degrees (also suitable for direct serial upload to a GPS unit, after first unzipping and loading into a freeware program such as g7towin). For OziExplorer users (after first loading and calibrating a map): To open the saved, unzipped file, select the "Garmin" menu button on the OziExplorer toolbar, then "Select PCX5 support",  then "Get waypoints from GRM file". If you require another format you will need to convert the downloaded file using freeware such as GPSBabel.

4. Create an intended Route by selecting Waypoints from the Listing in a suitable sequence for your walk.

5. Print off a hard copy of your Calibrated Map showing the Waypoint locations and your planned Route.  (See separate note below on the potential for uploading of custom map information to your GPS unit.)

6. Upload (transfer) the Waypoints and Route to your GPS unit from your PC through an Interface Cable. This eliminates the very slow and very frustrating task of manually inputting Waypoints and Routes into your GPS.

7. Save your walked 'Track' -  When you are on your walk you will no doubt at times decide to vary your path from the planned Route. For that reason it is very useful while walking to record and save your actual 'Track' in your GPS. You can then download it into your PC after your walk to compare with your original planned Route and make any changes that you might prefer if you plan to walk in the area again.

Buying your first GPS unit  - The main brands of hand-held receivers offer a large number of models with prices ranging from around A$200 for a basic or entry-level unit to close to A$1000 for units with greater loadable memory size, built-in road maps and larger screens. Be wary of over-investing in capability and features that you may not need or use. The entry-level units are quite adequate for most bushwalking purposes and are generally smaller, lighter and simplest to use.  This site, WalkGPS, is non-sponsored and is not an agent or retailer for any brands of GPS units.

Using your own maps  - Your own walk maps (and those on WalkGPS) created from scanned base maps and loaded as image files into GPS mapping software need to be used as hard copies. They cannot be uploaded to your GPS unit. A typical hand-held unit does not import or support maps in that form, but requires a database of digital (GIS) map information to be able to display the map.  Waypoints, routes and tracks can be readily uploaded, but if you want to prepare custom map information that is uploadable to your unit you will need to use a database program (e.g. cGPSmapper program for Garmin; also see an article on that subject). The OziExplorer GPS mapping software cannot upload maps to a handheld GPS receiver.

Many GPS receivers suitable for bushwalking have the capability to import maps (e.g. Garmin eTrex Vista Cx,  Legend Cx & Magellan eXplorist 500), but you will need  digital topographic map data ('vector' maps, not 'raster') for your area at suitable scale.  Australia-wide vector map coverage includes:  “GPS Topo PLUS Australia 10”, suitable for use with Garmin Mapsource software and some hand-held Garmin GPS receivers (e.g. Garmin eTrex Vista Cx, Legend Cx); and “DiscoverAus Streets & Tracks Topo”, suitable for some of Magellan’s eXplorist series receivers (model 400 upwards).  Also see maps suitable for GPS receivers.

Datum  -  The walk maps on this site (WalkGPS) use a UTM position format and a 1 km grid. Select the UTM (Universal Transverse Mercator) System in your GPS unit to determine your position rather than Latitude and Longitude. Using the UTM System simplifies the process of getting map location information into the GPS unit and vice versa. Also the UTM system (with its Easting and Northing grid coordinates in metres) is more practical for field use and helps obtain more accurate location measurements off a map. Select the datum setting in your receiver to match the datum of your hard-copy map (e.g. AGD66 or GDA94) if you wish to read-off and hand-plot coordinates for locations from your GPS unit onto your map.

Before starting to walk  - It is very important to leave the GPS unit on for a few minutes (up to about 5 minutes) at the start point of your walk, before you start walking.  This gives the receiver time to lock on to as many satellites as possible and to get an accurate starting location. If you do this the receiver will be able to maintain accurate location information during the walk and even if you turn the receiver off temporarily (e.g. at a rest point) it will be able to quickly and accurately find your current location (usually in 15-30 seconds). If you don't give the receiver time to lock on at the start point it may not be able to maintain a lock onto sufficient number of satellites and will then not give accurate location information during your walk.

New waypoints  - One of the great benefits of using GPS is the ability to accurately record the position of interesting features that you come across on your walk that you may want to be able to revisit in the future.  This is especially useful for locating small or subtle features that would have been very difficult to find again using traditional compass navigation.  When marking a feature as a new waypoint it is useful to give it an appropriate short descriptive name (instead of a number) to help remember in the future what the feature was.

Off-track walking  - When a route is 'off-track' (i.e. when it is not along an existing track, 'trail', or 'path'), the easiest walking between each pair of waypoints is often not exactly along the straight line that is shown on the map. When walking off-track, you need to be prepared to pick your own sensible route to the next waypoint by looking ahead and varying from the direct line to bypass local obstacles such as patches of thicker vegetation or unnecessary multiple stream crossings.

Battery life  - Battery life for the Garmin eTrex (which uses two AA batteries) is only sufficient in normal mode for about 10-12 hours of continuous operation, but this can be extended to about 22 hours in 'Battery Save' mode. 

Lanyard  - Always keep your GPS unit securely looped onto your belt or clothing by a lanyard. The hand-held units are small and very easy to leave behind at a rest stop unless attached to you!

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This page was last updated  :   17 April, 2008

 Site authored by David Osborne.  Photographs and text are copyright  © 2003-2008 David Osborne.

This page has been accessed times since 15 Feb. 2006.