Navigation Scatter Basics

In a scatter rally, crews fan out from a start point to visit several locations where they hope to find an answer to a question, just like a treasure hunt. Unlike a treasure-hunt, the clues in a scatter are primarily map-based, and owe a lot to road-rallying.

The examples in this document are based on Landranger map 183, titled "Yeovil and Frome", which is the map on which the July 13th 2003 Sunday Morning Scatter is based. If you are taking part in the Scatter, or want to follow the examples in this document, you must have Edition C1 (revisions for 2001) of this map.

The basic skill needed is to read an OS map. These differ from typical road-atlases, but share the same fundamental concepts of pictorial representation of the land. If you can use a road atlas to get around in the United Kindgom, you can learn to solve navigation clues and take part in scatter rallies. The one thing you are going to have to learn to do without is an index - there just aren't any.

What you will need to learn is

The other basic skill you will need to develop is using the map to navigate the car along the lanes. Having marked your points on the map, and decided how to get around to visiting them all, you need to translate the map markings into a series of instructions. At the same time, you will need to obtain information from around you to be able to keep track of where on the map you think you are, and revise this estimate whenever the opportunity arises. This skill is best developed by practical experience.

If you know where you are on the map, and which way you are going, you will be able to get to where you want to be.

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Grid references on the OS Maps

Road-rallying uses the Ordnance Survey Landranger series of maps. These have, in addition to information on buildings, roads, and significant landscape features, a superimposed grid allowing any point on a map to be expressed precisely. For example, on map 183, the town of Ilchester can be found in the bottom left corner, the name "Ilchester" largely lying within the square defined by grid lines 52 and 53 along the bottom of the map (Eastings), and grid lines 23 and 24 up the side (Northings).By convention, only the lower of those two number need to be specified, so 183/5223 means "the square on map 183 starting at 52 East and 23 North". Although grid references can be specified to a greater degree of precision than this, the Sunday Morning Scatter will give all map references as GS (EE) (NN), or GI (EE) (NN) for the intersection of two grid lines.

Remember this by whatever helps it stick in your mind - East first, North later

Here is a very simple example of a clue using the "running-narrative" method, and giving grid squares as checks. Follow this on map 183.
DirectionsEnd location
Start from the church in the Northover district of Ilchester (bottom-left corner of Map 183)GS 52 23
Follow the brown road to the roundabout and take the third exit, on the B3151GS 52 23
Take a right-turn towards Yeovilton, go into Limington and turn left at a T-junctionGS 54 22
Go through Draycott and Ashington, then turn left to MudfordGS 57 19
At the T-junction with the main road turn left, then turn left again at the next cross-roadsGS 57 20
Go through Hinton and into Chilton Cantelo, take a rightGS 57 22
Pass a building on the left, and then take a left turnGS 58 22
Pass a farm and a windmill. Your question is "What are the names and distances on the footpath sign close to the stream?"GS 58 22

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Coloured Roads Only (CRO)

Roads on the OS map fall into two categories, Coloured roads, in descending order of importance are Whites are the remaining roads, which may not be metalled or even gravel. Most road-rallies concentrate on the yellow roads where traffic levels should be less. Various conventions exist to tell navigators if they should be looking for white roads to find the shortest route from A to B. The convention that will be used in the Scatters is Coloured Roads Only, so you should not look for a way through using White roads unless the clue specifically tells you to do so, in which case you will see "Use ALL roads", "Use whites", or "use a white" somewhere in the instruction for the clue.

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Only roads that Go are shown

Some clue methods show road junctions where the crew should either ignore or take side turnings. Herringbone and tulip diagrams are the principal methods. A convention to be used in the scatter is that no diagram will be given when the side road is a no-through road, since this can be seen clearly from the map in most cases, and often from inside the car by the presence of appropriate road signs. If for some reason the organiser feels that they should show you the presence of a no-through road, it should be clearly marked by a T end. Similarly, if a white road needs to be shown at a junction for clarity, it will be shown dotted.

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Markings on the road

A route can be defined by general directions - go to village A, then on to hamlet B. This raises a problem if more than one road goes from A to B. By convention, the rally route is the shortest of all possible choices, so the organiser has to find a way of stipulating which of several routes the crew should stick to. This is usually done by "markings on the road". If the letters sl of the name "Apsley" obscure part of one of the roads between Apsley and Beaufort, then specifying "go from Apsley to Beaufort via sl" should clearly indicate which road is to be taken. Other good markings are spot heights. These are numbers, with an associated dot. These dots frequently occur right in the middle of the road, because surveyors dislike getting their feet muddy. Specifying a series of numbers can define a route that contains those numbers, in the sequence given, on several of the roads. By convention, the numbers are given in the order in which they should be traversed. If they are not in sequence, this will be clearly stated in the Sunday Morning Scatter clues.

Not all of the information is shown

There is a bewildering amount of information on an OS map, especially when you are looking at it under a dim map-light. There will be hundreds of spot-heights shown, except for the figure that you are looking for. For this reason, you might not be given every single piece of information that lies on the roads you are supposed to follow. If, for example, the organiser has given you three spot hieghts 120, 105, 84, and you find a route that connects these but also goes through the letters "sl" and the digits "24" (assume it is a grid line), there is no reason to mistrust your route. If the route you find also goes through a spot-height 135 but the organiser has not mentioned it, look to see if there are any other roads which also go through the same sets of numbers but avoid the 135. If there are none, then stick with your first choice.

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Do as you're told

The route can be specified as a series of instructions from the left seat to the right seat

Don't do what you're told not to

DNGT's are a nightmare for some crews. (DO NOT GO THROUGH). In a previous section "Not all of the information is shown", with a route joining SH's 120, 105 and 84 and also going through 135, if the organiser had specified DNGT 135, (or DNGT SH > 125 or Do Not Exceed 125 metres), then your choice of roads would have been wrong, and you would have to look again at the map. DNGT's are a nice way of constraining the crews to a series of roads, and can be easy to implement. From the point at which you are looking to decide a direction, find the DNGT given, come back from it towards your position on the map until you reach a junction where you have to decide which way to go, and cross off the road leading to the DNGT. If you are looking at a crossroads wondering which way to go, two DNGT's close off the roads leaving you with the desired entry and exit points. If you are given a series of DNGT's, try thinking about the problem from the orgaiser's viewpoint. There are no marks at all on the road I want them to take, all the information seems to be on the roads I want them to steer clear of, so lets's make them all out-of-bounds.

Here is a second simple example of a route, using map markings, and DNGT's, on Map 183. This time, there are no hints.
Start from the church at Ilchester in GS 52 23
23 16 26
DNGT 44
23 21 lto lo
DNGT 22
"What are the names and distances on the footpath sign close to the stream?"

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Not so pretty pictures

The previous route definitions have gradually become less verbose, and now we arrive at the most terse descriptions of all - tulips and herringbones. Tulips can be more friendly, but either method requires graphic thinking - chanting "132,132,132" can often help you locate SH 132 on the map as your eyes rove over it, but how can you repeat the pattern that roads make at a junction?
Convention is that a Tulip has a dot on the stalk you approach from, and an arrow on the path you exit on. The tulip should replicate the characteristic pattern of the roads at a junction, and again convention shows tracks as dotted lines.
The herringbone by contrast shows the roads you do not take, leaving a dead straight line for the road you travel. Like the DNGT's herringbones require thst you think not about where to go, but instead about where not to go. Consider the same short section of route, described by each method

Tulip diagrams
Hairpin right Turn left at a 5-way crossroads (2 arms are tracks)Take the 3rd exit at a roundabout
Herringbone diagram

Notice how harder it is with the herringbone to pick the pattern of the junctions. However, the herringbone can often be called "on the fly" because it tells you what roads to avoid. The navigator would call "Pass a left or take a right, go left at a 5-way juntion with tracks, take the third exit at the roundabout". It is sometimes easier to drive the herringbone than plot it on the map.

Here is an example using Tulips, on Map 183
Start from the church in GS 52 23
"What are the names and distances on the footpath sign close to the stream?"

And the fourth example uses a herringbone.
Start from the church in GS 52 23
"What are the names and distances on the footpath sign close to the stream?"

The clues have become increasingly terse as we have progressed through the examples. The early narrative style is fine for a shopping trip, but the skill in rally navigation comes from taking the terse description the clue-setter gave and finding the right spot at the end of it.
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Scatter versus Rally

In the previous examples I have used the phrase "following the route", as if the crew were in motion. In fact, although the clues for road-rallies and scatters are almost identical, the scatter crew have the (dubious) advantage of not having to actually drive along the course they plot. All they need to do is establish the end point, mark that on the map, and visit it by whichever road they choose. Once they have written down the grid-square that the end point is within, the pencil markings can be rubbed out on the map along the roads, leaving just the circle and number.
The downside to this is the lack of verification - once the scatter crew have marked their points they are committed to them, and there will be no marshalls or code-boards by the road to indicate that they are on the right course.
On the plus side, there is no time schedule to keep to, so the crew can stop and re-plot the clues if they suspect that they are not in the right place. If the clue told you that you would find a water-hydrant in a layby and you find yourselves with a layby but no hydrant, or hydrant but no layby, you have probably mis-plotted. Sit down, think it through, and have another go. The chances are that your mistake will not have put you miles away from where you should be, and the car roof or bonnet is as good as any table for plotting on.

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It would be great to claim I know all of the above because I'm so intelligent, talented, and generally the most brilliant being in the universe. And, while that may be true, I must acknowledge the efforts of others that inspired me to start organising scatters.

The following sites taught me most of what I know, and probably contain a lot that I ought to know but haven't yet got around to learning about.

There are bound to be sites that I have missed. If you know of any, please e-mail me with the url and I will be happy to add the site to the list.

adrian@scimitar-parts.com

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