Finding North (Part 3) Friday, Jan 28 2011

Carrying on from Last week’s post about finding north – what do you do when NO-ONE has a watch or method of telling the time?  This one takes a little longer, but is just as effective, but again needs a sunny day. This is the last in the series.

1. Put a stick in the ground (or light sabre!), and mark where the shadow ends.

2. Wait for a while (half hour is good as the sun doesn’t move that much in a short space of time) and then mark where the shadow ends then.  (the example below has exaggerated the shadow movement for effect and clarity)

3. Remember that the sun moves EAST to WEST?  So if we draw a line between our two shadow points we are actually drawing an EAST-WEST line!  So, if we stand facing our stick we can work out which direction North is!

 

Of course, if you do have a watch – and time – at camp, an easy gadget is to make a sundial, putting pegs where the shadows end on each hour (you may want to use some way to identify what the hour is – say, 10 clothes pegs for 10 o’clock…

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Finding North (Part 2) Friday, Jan 21 2011

So let’s say that you’re out on a hike and “someone” manages to break the compass.  The Leaders forgot to charge the GPS (typical!).  Luckily, you know where you are on the map – you’re at a cross roads and you need to be confident on the route that you are taking out.  BUT – which way is North?

Luckily, you do have a watch – and it’s a sunny day, so you can find North by using your watch!

So let’s start with the basics – in the Northern hemisphere the sun rises in the EAST and sets in the WEST.  At mid day the sun is at its highest point in the sky, it casts the shortest shadow – and is SOUTH (so the shadow points NORTH).

The small complication is that the high point is at 12:00 GMT or 1pm British Summer Time.

For our example, it’s the May Bank Holiday and a couple of hours after breakfast (around 10-ish).

1. Hold you watch flat – and point the Hour Hand at the Sun.

2.  Then draw an imaginary line pointing straight from the 12 o’clock position

3. Work out half way between the two points.  That’s South – so North is the opposite direction!

For those of you who have digital watches, you will need to estimate where the hands are on your watch….

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Finding North (Part 1) Friday, Jan 14 2011

Over the next few weeks, I thought we should talk about finding North.  You can use things such as floating magnetic needles, but typically very few people carry all that stuff with them.

As next week is a night hike, I thought I’d start with  finding North using the Stars.

For brevity, I will only focus on the Northern Hemisphere.  For anyone in the South, the Southern Cross is your guiding constellation – using the stars furthest left and Right, follow to the right to get to the South Pole Star.

I’m going to focus on the easiest star constellation in the sky to find the North star – the Plough (or Saucepan).  If you were Alaskan, you’d find this one EASY to spot – your flag is the Constellation!

Now, Once you’ve found the constellation in the sky (you are going to need a fairly clear, dark night of course!), you can use the edge of the saucepan and follow it up and away to a star that looks like it’s on its own – that’s the North Star!

You can double check this by using the mid point of Cassiopeia (it looks like a “W” on its side), but it’s a less reliable route.

(Thanks to How Stuff Works – http://adventure.howstuffworks.com/survival/wilderness/true-north3.htm and http://scienceblogs.com/startswithabang/2010/06/happy_belated_flag_day_from_th.php for the information!)

As a final note, I have also found out whilst writing this that the Orion Constellation can also be used – the 3 stars that make up Orion’s “Belt” run East to West, so you can use that to get the general idea of a northerly direction!

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Pathfinder Weekend report Monday, Oct 18 2010

Pictures: http://www.flickr.com/photos/frog101/sets/72157625189608810/

Ivor and David met the first group at the Church, before driving round to the 19^th and picking up the last Scouts and all the camping equipment.   We then drove up to Lees Wood with just about enough light to get the tents up.

With a little struggling by the Scouts – and leaders wondering why the tents weren’t reaching the ground all the way round – the site was prepared.  The other members of the District (Vince estimated that there was about 60 present at the weekend) were setting up the tents, or exploring the site – or having a go on the Radio (this was also a weekend for Jamboree on the Internet – JOTI – and Jamboree over the air – JOTA).  It was nice to meet up with the boys that we had taken to Kandersteg, Switzerland as part of the District Contingent – and really pleasing that we could remember their names too!

Once our site was ready, we drove to Sainsbury’s so that the Scouts could buy the food for their menus.  This was quickly sorted and we returned to base.  Surprisingly for a first night, we settled down quite quickly and early.

Saturday morning was cold but pleasant – the boys cooked their breakfasts, made their lunches and we were ready to go quite early.  David drove the groups to their drop points; Ash and Alan were dropped at Coleshill (SU948953) and Ivor and Nandesh at Black Park (TQ005832) with a final destination of the Aquadrome at Rickmansworth (TQ056937).  Once dropped, David then drove between the two groups making sure all was OK.

The leaders walking with the groups hung back about 30 metres so the Scouts had to do all the work!

Fortunately, all was running to time and Alan and Ash’s group got to the Aquadrome for about 3:45pm; Ivor and Nandesh was about 30 minutes later.

Arriving back on site, the Scouts cooked their evening meals and washed up; they then listened in as contact was made with Scouts from aboard (Anand managed to make contact with a number of groups, including a group from Malta!)

 

Sunday morning quickly came round; the boys had to be pushed a little to make their breakfasts and cook all they had bought, but breakfast was sorted and with lunches packed both groups were dropped at the Aquadrome ready to walk back to Lees Wood.  Ash and Alan would use some of the Ebury Way before heading North to Croxley Green; Ivor and Nandesh headed through Rickmansworth to pick up the Chess Valley Walk.

Ash and Alan’s group had no problems on their walk and all went to plan.  Ivor however had a small challenge as for a short while the Scouts managed to evade them! Fortunately they were re-united and after a very brief lunch were able to walk onto site – although they still managed to take an unusual route to get to the base.

Back on site, the tents were dropped and the trailer was packed.  Because we were the only ones with a full programme on Sunday when we arrived back on site we were the only Scouts still there; it was a little surreal being the only Scouts on a huge field.  We drove back to the Cabin and after the tents had been hung to dry we let the Scouts go home.

 

It had been an interesting weekend, allowing the Scouts to demonstrate their map reading skills.  My thanks go to:

Ivor, Alan, Ash, Nandesh as Leaders

Anand, Aaron, Alec, Charlie, Frazer, James R., James Z., Nathan, Oskar and Steven

 

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Blank Route Plan Monday, Oct 18 2010

Should you find it of use, I’ve uploaded a blank Excel spreadsheet that may be of use for planning routes etc, plus a couple of additional web links to check the OS grid references and mapping distances.  It can be found under Training Guides:

http://2leftwellies.wordpress.com/training-guides/blank-route-spreadsheet/

 

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Reading 4 and 6 figure Grid References. Saturday, May 23 2009

As UK Scouts, we make use of the Ordnance Survey Maps as a standard for navigation.  So that we can get from one place to another, we use 6-figure “Grid References” to accurately identify the various points that we are talking about.  Using these references, we can create a route going from point to point (if you have a GPS device, these are often referred to as “waymarkers”).

 

On an Ordnance Survey map is a grid of Blue Lines going vertically and horizontally (there are squiggly blue lines as well, but they’re rivers and waterways )  Each of the blue lines usually has a number somewhere along its length.  The following is a map of Lees Wood Campsite:

 

 (Above: Lees wood map by Ordnance Survey.  See end of blog for further acknowledgements)

 Below is a simple grid diagram, with numbers along the top and the side.  In one square I have an eye – and I want to give you the grid reference for that.  Because it is such a big thing in the grid, I can give you a four figure grid reference  – 03 83.

There are many ways to help you remember the order of the numbers; the way I remember is drawing the letter “L” as you always go down first, then across.  Also, the zero in “03” is also important – if you miss giving it someone could read the reference as 38 3 – a wholly different place.

 

A quick exercise – what’s the 4-figure grid reference that has the two circles?

 

 

So that brings us onto the next challenge – when there’s only one thing in the square, four figures fine.  But that puts it into a 1km square area – not very accurate.  A 6-figure reference gives us a better accuracy – a 10m square area.

 6-figure reference isn’t much harder to do.  Let’s give a 6-figure grid for the Grey circle.  We know that the 4-figure grid is …. 02 82 (did you get that?).  What we do is divide that square up with ten more vertical and horizontal lines – effectively giving us a “decimal point”.  Just using a rough estimate, the grey circle can be calculated as :

02 grid line, plus it’s about 0.8 of the way across to the next grid line – 028

82 gridline, plus it’s about 0.3 of the way up to the next line – 823

 

So the 6-figure grid reference for the grey square is 028 823.

 

Soo… what’s the 6-figure grid reference for the square?

 

Other things to note:

1. If the object crosses the grid line, then the 6-figure grid reference will be a zero.
2. You may see a couple of letters in front of the grid reference – this defines a certain area and is especially important to start to pin point down the area that the grid reference refers to (in most hikes, this isn’t really needed as the map usually isn’t that big an area)
3. You can record 8-figure grid references; this is accurate to 1m square – and is mostly used by the military (and by GPS units… although many are never that accurate to start with!)

 

VERY IMPORTANT THANKS:

Lees Wood Map Reproduced from Ordnance Survey map data by permission of Ordnance Survey, © Crown copyright.

Image produced from the Ordnance Survey Get-a-map service. Image reproduced with kind permission of Ordnance Survey and Ordnance Survey of Northern Ireland.

 

 

Copies of Get-a-map mapping for teaching and classroom use:

Educational establishments may download sufficient copies of each map image as displayed on your browser to provide each pupil/student and teacher with an individual copy.

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