Absolutely nothing wrong with what the guy done, brilliant wee vid. Another way of remembering whether to subtract or add.......Mag to Grid, get rid. Grid to Mag, add. In other words, real life bearing (Mag'netic) to map (grid'lines)....get rid.
Very helpful, especially with magnetic declination in my area is 14 degrees west can mess us a compass reading to the map without subtracting. Thank you so much.
Great video. One of the very few to indicate that the orienting arrow has to point north on the map when lining up the median lines. Colin did get you on the fact that this isn't using a back bearing. 259 degrees would be your back bearing. To use resection using your back bearing you would just reverse the direction of travel arrow so that it points from the hill top to your baseline which is the river and line up your dial to 259 degrees and do everything else the same. aultguish1, be careful with your rhyme as it only works when you have a west declination. You do the opposite when you have an east declination. That could get you in some trouble :) sboxjunk, that's a popular mnemonic device "west is best, east is least", but that is when going from the map to the real world: true north from the map to magnetic north in real life. It is the opposite when going from real life (magnetic north) to the map (true north). He does it right in the video.
You are thinking about what to do when converting a map bearing to real life. He is taking a real life bearing and converting it to the map. Make sense?
So here is where the confusion lies. For west declination you add the amount when going from the map, to the real world. However, you do the opposite for west declination when going from the real world to the map.
So he took a bearing on an object and got a reading of 82 degrees. We know it is off by 3 degrees because of declination. He subtracted 3 degrees to plot a line of 79 degrees on his map. Now if it was reversed, lets say he looked at his map and saw an object at 79 degrees. He would then add 3 degrees and that would be the course he would walk to hit that target.
It can be confusing. Let's start with a fresh example. Let's pretend you have a 5 degree west declination for your area. Anytime you take a Magnetic reading with your compass and transfer it to the grid, you are going to subtract 5 degrees. So if you point your compass at a mountain top and it reads 360 degrees, when you look at your map the mountain top would be at 355 degrees on your map. "Mag to Grid" means to always subtract when going from magnetic to grid if you have a west declination. However, you don't subtract when going from the grid to mag. You do the opposite. So anytime you go from mag to grid you subtract and anytime you go from grid to mag you add. All of this is true if you have a west declination.
So how do you find your magnetic variation when away from the internet and in the middle of Wales? Also, does the magnetic variation have that declination all over the UK as well?
Magnetic variation depends on your location and is stated in the legend of the map for that particular area. The magnetic variation is different in other parts of the UK. Each OS map will state Grid North, True North, and Magnetic North and the difference in relation to each other at the centre of that particular map in the year the map was printed. The annual change will also be stated so the difference for subsequent years can then be calculated.
you can also find the declination if you take a bearing from an exact location on the map (where you are) to a known location again on the map. Then compare the magnetic and map bearings and you can find it without internet! ;) damn you read that on internet and i found that on internet :D
Nice well explained video , but you are not using back bearings , you are simply taking magnetic bearings and converting them to grid bearings then using a technique called re-section to find your position on a map
also each mark that looks like a degree is actually 2 degrees....so 3 degrees is a nice female singing trio approved by prince charles....sorry... 3 degrees is ACTUALLY 1 and a half "notches" on the compass
EXCELLENT!
THANK YOU!
Jack this a fantastic video - I've always struggled to get this element of navigaiton but you explain it really well!
Very well put together and presented video. Thanks for posting it. :)
Absolutely nothing wrong with what the guy done, brilliant wee vid.
Another way of remembering whether to subtract or add.......Mag to Grid, get rid. Grid to Mag, add. In other words, real life bearing (Mag'netic) to map (grid'lines)....get rid.
i would recommend to take 2 back bearings to get a better knowing of your location
Thank you, very helpful.
Excellent Jack
Well done. Thank you.
At last one I can follow
Very helpful, especially with magnetic declination in my area is 14 degrees west can mess us a compass reading to the map without subtracting. Thank you so much.
Really helpful video.Thanks
Thanks you explained it really well
Nice job!
It’s magnetic variation, difference between grid North and Magnetic North. MV!!
nice explanation. thanks.
Nice - Thank you
Further tip: The closer to you the landmark (from which you are taking the back bearing from), the more accurate will be your positioning.
Great!
brilliant
YAY JACK ! That was Sooooo helpful ! ! !
As a homage I'll always do it "JACKS WAY" %7™
3 degrees west declination, you should "add" not subtract
plus it would be a lot more accurate with a SIGHTING COMPASS that has a mirror and sight marks to look through
Why should you need three landmarks? Two should be sufficient, surely?
Great video. One of the very few to indicate that the orienting arrow has to point north on the map when lining up the median lines. Colin did get you on the fact that this isn't using a back bearing. 259 degrees would be your back bearing. To use resection using your back bearing you would just reverse the direction of travel arrow so that it points from the hill top to your baseline which is the river and line up your dial to 259 degrees and do everything else the same. aultguish1, be careful with your rhyme as it only works when you have a west declination. You do the opposite when you have an east declination. That could get you in some trouble :) sboxjunk, that's a popular mnemonic device "west is best, east is least", but that is when going from the map to the real world: true north from the map to magnetic north in real life. It is the opposite when going from real life (magnetic north) to the map (true north). He does it right in the video.
You are thinking about what to do when converting a map bearing to real life. He is taking a real life bearing and converting it to the map. Make sense?
So here is where the confusion lies. For west declination you add the amount when going from the map, to the real world. However, you do the opposite for west declination when going from the real world to the map.
So if you have a west declination, you don't add both times or both ways. You add one way, and subtract the other way.
So he took a bearing on an object and got a reading of 82 degrees. We know it is off by 3 degrees because of declination. He subtracted 3 degrees to plot a line of 79 degrees on his map. Now if it was reversed, lets say he looked at his map and saw an object at 79 degrees. He would then add 3 degrees and that would be the course he would walk to hit that target.
It can be confusing. Let's start with a fresh example. Let's pretend you have a 5 degree west declination for your area. Anytime you take a Magnetic reading with your compass and transfer it to the grid, you are going to subtract 5 degrees. So if you point your compass at a mountain top and it reads 360 degrees, when you look at your map the mountain top would be at 355 degrees on your map. "Mag to Grid" means to always subtract when going from magnetic to grid if you have a west declination. However, you don't subtract when going from the grid to mag. You do the opposite. So anytime you go from mag to grid you subtract and anytime you go from grid to mag you add. All of this is true if you have a west declination.
nice
6×Sin 25°=6ו42=2•25 miles
So how do you find your magnetic variation when away from the internet and in the middle of Wales?
Also, does the magnetic variation have that declination all over the UK as well?
Magnetic variation depends on your location and is stated in the legend of the map for that particular area.
The magnetic variation is different in other parts of the UK. Each OS map will state Grid North, True North, and Magnetic North and the difference in relation to each other at the centre of that particular map in the year the map was printed. The annual change will also be stated so the difference for subsequent years can then be calculated.
you can also find the declination if you take a bearing from an exact location on the map (where you are) to a known location again on the map. Then compare the magnetic and map bearings and you can find it without internet! ;) damn you read that on internet and i found that on internet :D
It’s printed on the map you Mong!
You're not taking "back bearings"
Nice well explained video , but you are not using back bearings , you are simply taking magnetic bearings and converting them to grid bearings then using a technique called re-section to find your position on a map
DENBIGHVIDS / WXPM: Same thing, just different names.
also each mark that looks like a degree is actually 2 degrees....so 3 degrees is a nice female singing trio approved by prince charles....sorry... 3 degrees is ACTUALLY 1 and a half "notches" on the compass
Use Mils. Used it for 50 years in the British Army. Best in the world!
The top of the names do not indicate North. He aligned the orientation lines of the compass incorrectly.
You're wrong , names on maps are written from left to right , or west to east , so the top of a name does point north
Pp