Bushwalking Navigation | A Route Plan Workflow

How should I begin my route plan for a bushwalk? What resources are there available on the web? Are there any time savers? How do I  keep others in my group informed and allow active participation in the decision making? How do I take my route plan with me and share it with others in my group? Who should I tell about my route plan? Do I need an escape plan?

Introduction

A route plan is an essential part of any walk for three reasons; firstly as a way of easily checking whether the walk you have planned is too easy or too difficult in the time you have allowed, secondly as a way of improving the safety of your walk by sharing the route with others in your group, police, park rangers and friends and finally as a practical navigation aid.

Fortunately, few of us need to navigate in a whiteout, but if we do, a route plan which gives the distance and bearing of each leg and has chosen prominent waypoints as end points is an essential safety component.

An Example of  a Route Plan for Skiing and Climbing

Despite the importance of the route plan as a planning requirement, route plans are made to be broken and can become a liability if they are adhered to despite the weather, condition of the group and terrain. A good leader must be willing to vary the route plan to suit the circumstances!

A good route plan depends on the quality of the waypoints it uses, the selection of which needs to be based on sound navigational techniques some of which are listed  below. A waypoint which can only be found with a GPS is useless if your GPS fails and it will!.

Aiming Off

Used to find an objective on a feature which is straight eg river, mountain ridge, road

• Deliberately aim to strike the feature 10 ° to right or left of feature and then turn along feature to reach objective (also called Stefansson method or intentional error)

Attack Points:

• A feature which is near but much easier to find than your objective.
  

Catching Features:

• Prominent features which are beyond your objective but can act as safety net. 
• A bearing on prominent feature at 90 deg to direction of travel can be used.

Handrail:

• Definite features which are roughly aligned with direction of travel and  which make navigation easier.
• Don't use creeks or gullies but may run parallel to them.

In Poor Visibility:

• Stick to well defined features or proceed from one well defined feature to another. 
• Navigator 3-4 places from front, with party in single file.
• In snow, use a cord 50m long and have scout sweep in an arc until next pole found.

Pacing:

• A pace is the distance between each right foot hitting ground.
• For 1.8m person, with pack, ≈ 1.5m ie 660 paces to 1km.

Bearings

• Keep navigation legs short, moving from one identifiable point to the next, even if this involves a detour.
• Align straight edge of compass with 2 features, with arrow pointing in the intended direction.
• Rotate bezel until parallel lines on its base align with grid lines.
• To correct for magnetic deviation, rotate bezel clockwise (MGA: grid to magnetic subtract).
• Set out in direction of arrow with needle centred on its mark.

Back Bearings

• Used to see if you have deviated from the intended path.
• Face starting point.
• Check that south end of needle is centred on mark.

Transect Bearings

• Useful to locate exact position on a handrail.
• Identify a feature which is marked on your map then take a bearing on this feature.
• Convert magnetic to grid by adding the magnetic deviation.
• Rotate bezel anticlockwise.
• Place compass on map with arrow on base pointing towards the identifiable feature.
• Rotate whole compass until the parallel lines of bezel align with grid lines.
• Draw a line back using the edge of the compass until it intersects the handrail.
• Choose a feature which is as close as possible to reduce error.

Resection

• Used to describe process of drawing three intersecting transect bearings to find your present location.
• Select features which are at a maximum angle to each other. eg 120 deg

Route Planning Software

As a Mac user, I have only used the excellent program MacGPS Pro which I have had and regularly updated for many years. Australian PC users have OziExplorer which is also excellent and can be run on a Mac very successfully if you install Windows. If you have an iPhone you have other alternatives depending on your country; Australian's have Bit Map and Memory - Map, New Zealanders Map App NZ and Memory - Map, the British National Geographics Topo Maps. All of these allow you to rapidly plan a route by simply clicking waypoints  which are linked together and can then be uploaded to your GPS.

The other big advantage of mapping software is that you can zoom in at a magnification that you would need a hand lens to view on your 1:50K topo paper map. With just one click, you have  7 figure eastings and northings for each waypoint along with the map zone.  Distances and bearings, "as the crow flies", can be measured by two clicks. Route elevations can be plotted with a few clicks.

Once you have the route planned you can export it as a .kml file which can be loaded into mapping software such as that found on your iPhone, Google maps or Google Earth for others in your group to view. Alternatively you can export the waypoints as a spreadsheet which can be printed as part of your trip intentions form which you will give to your designated emergency contact and to the local ranger or police station or uploaded to Google docs for everyone in your group to view. Uploading to Google docs encourages participation in the planning process and a sharing of ideas.

Escape Routes

These are the routes you will take back to safety if anything prevents your progress to your destination. This could be an injury, the weather, too slow progress or physical blocking of your route by a landslide, avalanche, bushfire or flooded river. These should appear on the back of your route plan and be given to everyone who gets your route plan. Their format is identical to that used in your route plan. While some escape routes can be anticipated and planned in advance eg if a river you have to cross is flooded, others such as following an injury can't easily be planned. Of course, if you have a PLB or a mobile and reception, then in case of life threatening injury you can always call for help rather than follow an escape route.

Web Resources

Online Walk Time Calculator: use this online trip calculator to work out your estimated walk times for your route plan, using Naismith's Rule and Tranter's corrections for fitness.
Naismith's Rule
Online Route card  From 1st Kirklevington Scouts
      Automatically calculates times based upon inputted speeds and climbs.
Blank Route Card
Escape Route Template
What is a Route Card
   
Related Posts

Online Walk Time Calculator
Bushwalking Navigation
Mapping Software

This article by Bush Walker is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License.