Find your location on a map & identify features
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- Опубліковано 4 жов 2024
- Being able to locate your position and identify a ground feature on a map and, if necessary, adjusting for declination, are important skills all navigators should have.
In this video I have used a Cammenga lensatic compass but this technique will work with any reasonable quality compass. If you are using a baseplate compass:- where I have used the tritium mark use the orienting arrow.
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Please note there is an error on the video. At around 2:35 I say that you should rotate the dial anti-clockwise if your declination is west, however this would be the case if you were taking a bearing from a map and using it to look for a ground feature (grid to mag). In the video I’m taking a bearing from a feature and using this bearing on a map (mag to grid) so you should rotate the dial clockwise.
Thanks to Rick Panyk for spotting my error and letting me know.
(if you notice any errors on any videos please let me know - we all make then now and again)
This must be the best channel so far I watched on this subject. Simple and no nonsense.
When I use the Cammenga I found that orienting the map gives me more accurate results. Reason, I don't have to rely on the luminous marker to align to TN and hence can get direct reading under the thin black line. Just my personal experience.
The more I watch this channel, the more I like it. Thank you so much!! 😁👍🏻
Your adjusting compass for declination is another shortcut that works without having to orient the map. Your second set of lines plotted the compass bearing as if the map had been oriented. Shortcuts that work but confusing unless you explain why they work. You should orient the map for clarity.
Minor point. If you had the map north-up and you were on the other side, the shaddow wouldn't be so distracting. I always set the map to north-up and adjusted for declanation before starting any sighting. Good video all the same.
I love this channel it’s peaceful and refreshing compared to all the other content on UA-cam
Clear and concise explanation. Better than on the most of other channels.
I miss one little thing in this video. Your three lines intersect nicely in one point, your location. I know it's just an example and it's correct, no problem. But in reality those three lines will usually form a little triangle where your location is. That's what I miss in your explanation.
Magnetic Variation and re- section with an old prismatic , What fun we had
I like the ticking sounds of the rotating dial. Great video btw
Very cool, if been hiking and taking bearings of points, and when home checking where i was, great fun
I’m confused. You must walk on sighted compass bearing. Your method of not orientating map puts your sighted bearings onto the map as grid north (protractor) bearings. Which is fine. You accurately plotted your position on the map. If you checked your first set of drawn lines with a map protractor you would see the degrees were different from what you set compass at. The lines and location remain unchanged, declination adjustment is made from grid (protractor) bearing which will get you back to your sighted compass reading to begin with.
Thanks
Great video. I learnt all this during flight training. Its good that its no different to orienteering.
Question - which compass do you prefer using, the baseplate compass or the Lensatic compass in your video?
I have lots of compasses, but you’d expect that given my job. My personal compass is the Silva expedition 4 which I find to be ideal for trekking and walking around the countryside.
Mind you,
If I was a geologist I may use the Brunton TruArc 20.
If I was a soldier I may use the Francis Barker m73
If I was an orienteer I may use the Suunto Aim 6
If I was a rambler I wouldn’t use a compass at all, I’d just use a map.
Etc.
One that I want for my birthday:
Dalvey engraved Grand Voyager with full hunter and Albert in Blue Pearl :-)
Note: I’m not on commission nor do I receive any form of payment or benefit from any compass manufacturer.
@@TheMapReadingCompany Ill take a look at those compasses. Thanks.
Great video, learning a lot from your channel, thank you. How would you identify features with a baseplate compass such as my expedition 4?
Instead of pointing the tritium mark up the map (northwards) point the orienting arrow on a base plate compass (Silva, Suunto, etc).
The orienting arrow is in the center of the orienting lines, inside the dial
see here ua-cam.com/video/LVf0v0TqoOg/v-deo.html
Question: If there is a magnetic declination in your area and you're trying to get your location by triangulating from three visible landmarks without adjusting, will the lines still intersect perfectly? Or would they be way off and be an indicator of something needing adjusting?
If there is declination in your area you need to adjust for it one way from a map to a compass and in the opposite direction from a compass to a map.
See this video for a better explanation. ua-cam.com/video/FT8y31Hscow/v-deo.html
Here is an idea for you. Show us how to use a school protractor to get a bearing. If someone forgets the steps to use a lensatic compass they can go to a protractor.
If someone doesn’t know, or forgets how to, use a compass is it likely that they’ll remember how to use a (US) GTA 5-2-12 or (UK) RA protractor. Also how many civilians carry either of these?
But you never know :-)
I have a VERY long list of videos either partly filmed, waiting to be edited, planned, etc. So I'll add protractor to the "maybe" list.
I use a simple half circle, unbreakable plastic, grade school protractor. I have a military protractor that I can use.
Sir when using map and compass, can can you set declination before finding your location as in this case?
Where do you find the magnetic declination?
How do you orientate your map?
Hi Vincent thanks for joining the conversation.
To find the declination depends on where you live, for example:
If you live in America you can use this website
www.ngdc.noaa.gov/geomag/calculators/magcalc.shtml
If you live in the UK, try this
www.geomag.bgs.ac.uk/data_service/models_compass/gma_calc.html
This website uses the WMM (World Magnetic Model) 2020 so it’s slightly out of date but for trekking and walking the difference is so small it won’t be noticeable.
www.magnetic-declination.com
As for orienting your map: You only need to do that if you’re not using a compass. Just follow the steps in the video and it should work. If you’re not used to working with declination then you could do each step one at a time whilst pausing the video.
Sir at what point do you, set declination?
how do i know if magnetic declanation is applicable where i am standing ? what gives you this info?
1 Find two points of your map which you can identify on the ground and go to one of those points. This could be a road or wall junction, a trig point, a bridge, junction of two rivers, etc. Basically anything which is the same now as it was when the map was printed.
2 Take a compass bearing from your location to the other point.
3 Take a bearing from the map your location to the other point.
4 Compare the two bearings. The difference is the current local declination.
@@TheMapReadingCompany ahh thanks so much appreciate the reply
one last question ,
As an astro photographer i need to have my mount pointing towards Polaris but sometimes i dont have the luxury of seeing the north star , so which compass would you recommend to get me facing towards Polaris as close as possible ? , this is needed and most important when placing the tripod
thanks again kindest regards
I didn't understand one thing, when you put the declination of 15 degrees west, going from compass to map you should have subtracted it, turning the Cammenga bezel clockwise. Am I doing something wrong? Thanks for your help.
Ciao Luciano, declinazione ovest è una rotazione in senso orario. Guardare questo video, ci sono più dettagli su regolare una bussola (lensatic) per la declinazione. ua-cam.com/video/uzhTa-5rIEw/v-deo.html
😂 si lo so . . . . . . . il mio italiano è terribile
ua-cam.com/video/sFdN4SlHqcs/v-deo.htmlfeature=shared
@@TheMapReadingCompany il tuo italiano è ottimo 👍🏻
He's acknowledged the mistake in the video description area. I t did fuzz my mind a bit till I saw that cos i trust his advice more than my own.
But the tritium mark signifies what, I mean, NOTtritium, I suppose….
Yes the mark does have tritium in it - so it glows in the dark.
See this video: ua-cam.com/video/RjuEmOar-DQ/v-deo.html