Compasses to point true north for first time in 360 years in UK
theguardian.com
theguardian.com
That said, orienteering is one of the most valuable skills I think a person can learn but it can be hard to grasp learning solo. For those not familiar there are really two ways to go about it: - Dead Reckoning - Terrain Association
Dead Reckoning is all about planning waypoints and using your compass and pace count to get you there. For example: I need to walk 5km at 220° then 2km at 90°, etc.
On top of that, it's easy to make simple mistakes when planning your route. Errors when converting from grid to magnetic(and visa versa) can put you off by a few grid squares so it's important to understand terrain association which is a technique of studying the terrain on a map, plan a route and use those visual terrain features to guide you(If the river is supposed to be on your left but it's on your right, something is wrong).
Having both techniques in your back pocket are essential, but like any skill, they're perishable so you have to practice often.
Some key mistakes people tend to make when orienteering: - When you're dead reckoning through the forest, make sure you switch which side you favor. For example, if your compass points directly at a tree do you step to the right of it to go around or to the left? Most people will pick their dominant side and tend to veer to the right over time. This won't be corrected by staying on a specific azimuth. - Night time is challenging when orienteering in a forest with no roads/creeks/etc to handrail. You often can't see more than 10-20 meters and there's no terrain for you to associate with. - After you plan your waypoints out, do it again from scratch. You likely made a mistake. The protractor you used to get your heading represents your grid angle, every map will have a GM Adjustment(grid to magnetic) you'll need to make.
Source: I'm a former US special ops soldier with hundreds of hours using a map and compass humping through the woods.
I'm a sucker to GPS as well!
Are the maps specialised for orienteering? Since I've never seen that info on a standard street paper map.
Is it something that a digital compass could automatically do? Especially since the article is indicating that magnetic north drifts.
Useful tool: http://www.magnetic-declination.com
The older the map the less useful it is. You then have metal in the local rocks which can cause problems.
Terrain recognition is far easier, there is far more error correction built in, but if you are hit by a patch of fog and visibility is down in to 30m (let alone 3m!) you need dead reckoning.
Trouble is even a 1 degree error can turn into significant errors after a very short distance.
The magenta dashed line going from top to bottom at a slight angle on the left of this image indicates degrees magnetic declination. https://www.faa.gov/air_traffic/flight_info/aeronav/media/VF...
As for specialized maps for orienteering: Orienteering maps are different than normal street maps. They always have gridlines, very precise scales and clear markings of major and minor terrain features[2].
Then, on top of the data presented on a map you have maps of different scales. For example, one inch of a 1:24,000(pronounced - one over twenty four thousand) map represents 24,000 inches on the ground. A 1:250,000 map it very zoomed out relative to a 1:10,000 map.
If you're hiking 500 miles of the PCT you may want a 1:100,000 or 1:250,000 scale map because you don't need to know every twist and turn because you're following a trail.
But if I dropped you off in the middle of nowhere and said walk due west to a specific point 10 kilometers due westyou'd want a map that's 1:10,000-1:24,000 scale because you need to see specific terrain features.
To answer your question more directly: There are what you would "orienteering-specific" maps because they represent some critical data well. For orienteering you use the one that works for you based on what information you need to get you from point A-B
[1] - https://www.idownloadblog.com/2017/04/28/how-to-iphone-compa... [2] - https://pubs.usgs.gov/unnumbered/70039582/report.pdf
https://maps.ngdc.noaa.gov/viewers/historical_declination/
edit: Some more on this stuff here (probably to be taken with a grain of salt, but neat no less)-
Magnets are more or less bound to point somewhere on a planet containing a core of molten iron, but my understanding is that it could easily have been towards Australia, or Mexico or anywhere.
If magnetic north was located in Mexico it would still be of use, assuming it was relatively constant.
...and the map is also the same device.
[1]: https://en.wikipedia.org/wiki/MEMS_magnetic_field_sensor
Enclosures are all either plastic, aluminum or magnesium. Circuit board will be copper. Maybe some internal structural elements or RF shield cans are made of steel?
Microphones are MEMS these days, so no magnets there. Speaker magnets are tiny and also tend to have weird magnetization patterns that seem useless for making a compass (e.g. disc with a circular channel for the coil where N-S are inside of the channel)
In other words, the skill is about as rare or rarer than the equipment.
Though every few million years, the north and south magnetic poles swap, for unclear reasons.
Also, it cycles at 300,000-400,000 years not millions.
[1] https://futurism.com/earths-magnetic-poles-overdue-switch
I hoped "every few million years" was vague enough that I didn't have to look it up, but sometimes you gamble and lose :)
It could be. Since we've never seen a shift, we don't really know how it looks.
And a shift takes a few thousand years, so we can probably be centuries into it before it's clear what's happening.
I doubt the geological record is fine grained enough to tell fast oscillations apart from a slow drift.
"Almost always" is a term of art in probability theory, where it means p = 1 despite the existence of possible outcomes that defy it. For example if you keep tossing a (fair) coin it will /almost always/ eventually come up "Heads". But I guess here you mean something else and I'm not sure what.
That's a somewhat misleading term! I much prefer "probability one".
> But I guess here you mean something else and I'm not sure what.
Read it literally. The everyday definition of "almost". In other words, "the vast majority of the time".
"almost always" is more like a 95% threshold, sometimes higher but with an implication that failure is realistic.
“probability one” is misleading, too, as laymen would assume the reverse cannot happen.
The interpretation of “almost always” as ”p = 1 despite the existence of possible outcomes that defy it” likely is based on http://mathworld.wolfram.com/AlmostEverywhere.html (which has “almost surely” as the mathematical expression, but I would immediately read “almost always” with the same meaning)
In the real world it cannot happen. It can only happen in an unbelievably unlikely mathematical abstraction. So I would call that layman understanding closer to the truth.
"From these models and extrapolating down into the Earth, it is known that regions of reversed flux at the core-mantle boundary have grown over time. In these regions the compass points in the opposite direction, in or out of the core, compared to that of surrounding areas. It is the growth in area of such a reversed flux patch under the south Atlantic that is primarily responsible for the decay in the main dipolar field. This reverse patch is also responsible for the minimum in field strength called the South Atlantic Anomaly, now centred over south America. In this region energetic particles can approach Earth more closely, causing increased radiation risk to low Earth orbit satellites."