Navigation
An Introduction to Rally Navigation by David Brown MKDMC
 
Introduction
There are many methods of providing the information to define a route on a map. This guide aims to explain some of the commonly used techniques, and hopefully provide some of the skills required to solve the trickier methods.

There will always be new and unique approaches (some of which work, and some of which don’t!), and as these depend on the organiser & the route chosen (e.g. certain features may lead to a novel approach) these obviously cannot be covered here.

I hope that you find the information useful, and remember the old adage – if in doubt – panic!

The Route
The route to be followed will go from Start to Finish via a number of timed controls (TC1, TC2, etc.) using one or more plotting techniques for each section. Each road and junction can only be used once for the whole rally, and may not cross itself. However, look closely as some crossroads are in fact 2 staggered T junctions and so can be used as such – this should be clear on the map. Also dual carriageways can be regarded as 2 separate roads and so can be used in the relevant direction.

Usually it will not be clear exactly where a TC lies, but will usually be somewhere between the last instruction and the point where further instructions are required (e.g. a junction).

Using Numbers
There are many numbers on a map, and many ways in which they can be used to define a route.

Grid Lines
Numbered from left to right and bottom to top, these are 2 figure numbers relating to the blue vertical & horizontal lines on the map. 2 digits can be used as these will not be repeated within 100km in any direction (the grid lines being 1km apart). However the most comprehensive grid lines are….

The primary function of the humble grid is to be able to define a point on the map using a grid reference. This is usually in the form of a 6 digit number but can be expanded by fractions (e.g. ) or to 8 digits (or even more as shown below).



If in doubt this is shown on the map index (as I can never remember whether Eastings or Northings comes first!)

 



By using the full definition of the grid line a 12 digit map reference can be created, though rarely used.

The use of a Romer will aid in accurate map references. A Romer is a plastic rectangle with one corner marker in 1/10ths of a square (i.e. 2mm apart) and can either be bought from a good map shop, or made from thin card.



In this case the grid reference could be defined as;

152317 
(6 figure)

152 316  
(more accurate)

15223167
(10 figure)

415225231675 
(12 figure)
Note the difference in accuracy to the 10 digit above

 

 



A sequence of map references, commonly indicating junctions, could define the route, or could define ‘black spots’ which are ‘no go’ areas to be avoided.

Grid lines can also be used in a number of different ways. 

Crossing grid lines can be indicated by the grid line number, and a route can therefore be defined as a string of numbers indicating the vertical and horizontal lines being crossed e.g. 24 68 25 67 26 67 68 27. Note that there may be more than one road crossing any grid line.

To make life interesting these can be combined into a single string, or to make life really difficult could be in reverse order! So 2468256726676827 or 7286766276528642.

As the grid lines run vertically and horizontally then they can be represented by V and H, hence the sequence VHVHVHHV. Obviously this is a little more difficult that using numbers as it is not known which grid line needs to be crossed, and when taken over a number of instructions can lead to a number of feasible options until each one reaches the point where the road cannot match the instructions.

Another option is to indicate the direction one will leave the grid square. A number of options exist including NEWS (North East West South) and UDRL (Up Down Right Left). Note that this type of instruction can have different uses as shown later (I never said this was going to be easy!).

Finally, the position at which the route leaves the grid square can be indicated. This can include the distance (in mm on map, or 1/10 km on Earth) up or along the grid line from the intersecting line, a series of dots on a grid or each square shown with entry and exit points (see example below).

In this example each square represents a grid square, with the lines indicating where the road enters/leaves the square. Note that they are not in order (too easy!) so they would be used in the order 1 4 2 6 3 5 (the exit from one square is the entry to the next) – the squares would not be numbered!

Spot Heights
On every map you will see 2 or 3 digit numbers next to a dot (or a dot in a triangle) indicating the height of that point above sea level. These are known as ‘spot heights’ and are very useful for defining a route.

The most common method is to list the spot heights through which you must go, usually in order (but could be in reverse order or random). Remember that unless instructed otherwise the route must NOT pass through any unspecified spot heights.

Example; 136 125 89 63 95 143 or to put it another way 136125896395143

Road Numbers
Main roads have numbers e.g. A45, A509, B4037, etc. These can be used to indicate using or crossing this road as part of the route (usually omitting the A or B to make life difficult).

Non-decimal Approaches
To stretch the brain a little further some alternative ways of defining numbers can be used.

How about Roman numbers? CXVII (=117 spot height)

Binary? 100100 (=36 grid line)

Hex? Hopefully not!

(Personally I like Roman numerals – a sequence of which, with no gaps, can really slow down the expert crews!)

Combinations
As all numbers are equal a sequence of numbers (e.g. 5278405783252840278153) could be a combination of grid lines & spot heights with a map reference thrown in.

A Little Maths
As we have seen above, the organiser can try and disguise the route by missing gaps in sequences and mixing different types e.g. spot heights & grid lines. Another ruse is to apply some maths – usually addition.

The digits can be simply added together e.g. spot height 132 becomes 6, and hence a sequence such as 136 125 89 63 95 143 becomes 10 8 17 9 14 8 (or 108179148 for the demonic organisers).

Alternatively the sequence above could be defined as 136 -11 -36 -26 +32 +48, and this can be applied to any type of number.

Codes & Ciphers
It is also possible to disguise numbers in different ways. Using letters to indicate numbers can be as simple as A=1, B=2, C=3, etc. (starting at any number of course), or a 10 letter codeword can be used (e.g. LANDRANGER) where the first letter =1 (or 0), the second 2 (or1), etc. and a grid reference would then appear as NADDRN. The added sneakiness here is the double use of letters giving multiple options!

Another method is based on a phone keyboard where =1 =2, etc.

Roads
The roads themselves, and the junctions they form, can be used to define the route.

Firstly, the roads are coloured. In the norm all white roads are ignored (unless instructed otherwise). Therefore we go from the humble yellow road, through brown (or orange) ‘B’ roads to red ‘A’ roads, green trunks roads and finally blue motorways (not to be confused with rivers or canals which play havoc with your electrics!).

In this way the route can be defined as the colour of the road you are on, between any two junctions, hence YYYRRBYYBBYYY.

Also using these colours any junction can be defined e.g. 3Y (or occasionally YYY) is the junction of three yellow roads, and 2RY is the junction of a yellow road with two red roads.



Using this method a sequence such as 2RY 2Y2B 3Y 3Y 3Y Y2R will define the route. Note that the sequence of three 3Ys may provide a number of alternative routes, only one of which is correct, though this should become obvious from the next instruction (Y2R in this case).

Another way of defining a junction is by tulips. Nothing to do with flowers, they were devised during the Tulip Rally. A ‘tulip’ is a graphical representation of the junction as it appears on the map, sometimes indicating the approach direction (dot) and/or leaving direction (arrow), but often with neither! Watch out when there are a number of junctions close together!



If you now imagine joining up the tulips and then stretching them out into a straight line you get a herringbone. Usually running left to right they can run in the opposite direction, and/or can be mirrored! Novices will normally be warned of this!

As each junction is basically a line off to the right or left (except crossroads) this can either be ‘ignore road to right’ OR ‘take road on left’.



In the example above the first crossroads is ‘straight on’ and the second is turn right.

To make life interesting the line can become a circle, which may, or may not, have a direction and/or start point (usually indicated by a large dot). These are known as circular herringbones.

Look for distinguishing features such as crossroads.

 

 


Another way to use junctions is to provide the direction of which the junction is approached, or more usually left.

The most common of these is using a 16 point compass (i.e. N, NNE, NE, ENE, E, etc.) – a sequence therefore showing the direction in which subsequent junctions are left. Combine them into one long list, and the combinations will cause a few headaches!

NNWENESSSWENNE

Note - these can also be combined with other instructions to indicate the approach direction (ENE621894) or leaving direction (117NW).

The junction can also be represented by a clock face, the 2 roads being used (one to enter, one to leave) being represented by the hands of a clock. The time is usually given as e.g. 9:10 meaning, of course, ten past nine. Therefore 


Alternatively a single number may represent a clock face so in the above example these would be 2 and 9 respectively (or 9 and 2 if the number represented the approach direction).

The distance between junctions (in mm on map, or km on road) can also be defined, giving another sequence of numbers.

Roundabouts can be considered as a number of 3 way junctions e.g. 3R 3R 3R or miss right, miss left, miss right, both of which could indicate take second exit. Most organisers avoid using this type of plotting for roundabouts, or provide clear instructions.

Map Features
An O/S map contains many features, all shown in the index. The route will go past churches, phone boxes, pubs, etc, and these could be represented by a sequence of symbols. In addition any letters which the road passes through (e.g. town name written across the road) could be included in the sequence.

Another method is to indicate passing under power lines, over rivers or canals or over/under railways, motorways, etc.

One way to show this is using O and U (for over and under) giving OOOUOOUOUUO.

Alternatively the bridges themselves could be shown thus;

 

 

Longest Route
Under normal circumstances the shortest route between any 2 instructions is taken. Sometimes careful examination of the map must be made to determine which of 2 possible routes is the shortest.


However, on occasion longest route can be included in an instruction, and this will only apply to that section. This can be as simple as going around a triangle or other small loop, or can be mean investigating a number of possibilities, which hopefully do not disappear off the map! Remember that from the time card the approximate distance between 2 controls can easily be calculated (time 2 the rally is run at 30mph average unless instructed otherwise).



When to Panic!
Apart from the obvious use of ‘panic’, in rallying terms a ‘panic’ is simply a sealed piece of information providing the position of a control. Using a panic results in 1 ‘fail’, but if the plotting cannot be solved, or is taking to long, then by opening the panic and getting to the next control in time it will mean that you can plot the next section and get back on track. As a rule of thumb spend no more than 1/3 of the time available for a section in plotting – obviously extend this a bit if you are well though plotting the route – that what lateness is for!

Once you have plotted the position of the next control from the ‘panic’, work out the shortest route to get there, ensuring that the approach direction is correct (this should be provided, as in ENE612983).

Another way to use a ‘panic’ is when the plotting method is totally alien. By plotting the end point (next control) it is sometimes possible to decode the instructions or at least ‘guess’ the most probable route in the hope of picking up some POP boards on the way.

Conclusion
Hopefully this has given you a good grounding for plotting routes on 12 car rallies and similar events. It will not cover every eventuality but provides a useful toolbox of solutions. The other most useful factor is experience – this cannot be overestimated! Novice crews will normally get hints, simpler clues and additional time, etc. but as you get better these will be progressively withdrawn and you’ll be competing alongside the big boys!

Remember that a novice can win an event, and that somewhere out there an organiser is thinking up a totally novel way of defining a route. Good luck!