Author Topic: Sighting compass to improve accuracy (and realistic expectation of accuracy)  (Read 5578 times)

ninthace

  • Veteran Member
  • *****
  • Posts: 11824
The last time used a compass as a primary navigation aid for walking was 30 years ago when I had to cross a lump of Dartmoor in thick fog with a group as an officer under training with the RN. I have often used it to support my map reading to:
Make sure I was on the right path i.e heading in the expected direction in reduced visibility,
To help me identify features,
To get an idea of my whereabouts along a route,
To find my way across large fields where the exit wasn't obvious.
On all these occasions a standard Siva compass has been adequate. However, since the advent of gps with map displays, the sole use I have put my compass to is to find out what distant features are called.
Last time I used a sighting compass for navigation it was bolted to the bridge wing of one of HM's war canoes.  That was also the last time I really worried about variation  and deviation.
Solvitur Ambulando

Owen

  • Veteran Member
  • *****
  • Posts: 1760
Deviation in the UK isn't very large so you can get away with ignoring it, in some parts of the world it's far from an irrelevance. In parts of Canada it's 45 degrees.
If you always walk on manicured footpaths you won't need a compass. In other parts of the country that's not often possible. Up here in Scotland paths can be very faint or non-existent and visibility is often obscured by thick mist even in summer. I think I've been walking on a compass bearing about half a dozen times this year alone. Yes I could have gotten my phone out and used viewranger but that's more often than not buried deep in my rucksack and getting the compass out of my pocket is just far less faff.
I do have viewranger as well as several GPS's, I tend to use the Garmin in winter as I find it easier to use than the phone. Hopefully everything will be covered in deep snow and I'll be on my skis, which does complicate the navigation. That's where the Garmin comes in handy. The maps on viewranger are far far cheaper than on the Garmin so in Sweden I use viewranger (£15 for viewranger, £180 for Garmin).
The viewranger app was free and the maps are cheap but the phone was expensive. UK maps came with the Garmin but again the set was expensive. The Satmap was expensive, the maps were expensive and it wasn't waterproof, still you learn by your mistakes. A silva compass is still far cheaper, just needs a little practice. 

Snowman

  • Sr. Member
  • ****
  • Posts: 435
I know that the GPS vs. compass argument has appeared several times on this forum, but saw an article recently where a member of the Scottish MR made what I think are very pertinent points regarding use of technology in the mountains:


http://news.bbc.co.uk/1/hi/scotland/highlands_and_islands/6353559.stm

Snowman

  • Sr. Member
  • ****
  • Posts: 435
... however with regard to the original query, I have to admit that while I have a sighting compass, I've rarely used it.    I have a Suunto Nato compass and also a Recta compass that I bought because it has a declination correction feature, which I have found of rather more use than a sight.    These are my instruments of choice when trekking and I usually take them both.


I have used bearings for navigation and do think it's a useful navigation aid - I also did some ocean sailing back in the '70s when the height of technology was still the map, compass and sextant, and bearings with a sighting compass were vital when close to shore.   However I've never had to use one for navigation on land, since as has been pointed out, accuracy is a little debatable whatever compass is used.


As I said, I do have a sighting compass but I bought that primarily when trying to get my kids into the outdoors, so took them letterboxing on Dartmoor (a lot of the directions for letterboxes are given as bearings).








John Murphy

  • New Member
  • *
  • Posts: 18
I know that the GPS vs. compass argument has appeared several times on this forum, but saw an article recently where a member of the Scottish MR made what I think are very pertinent points regarding use of technology in the mountains:





But that article was written over 10 years ago!Technology has moved on since then. :)  Although I have always used map and compass and gps as a backup as it gives you an accurate position when needed.

Pitboot

  • Sr. Member
  • ****
  • Posts: 464
Technology has certainly moved on. However, stupidity has not! On more than one occasion I have been asked to confirm a location or direction for people relying on a phone based nav system.
First case, the battery had run out and it was getting dark.
Next case, the app was not working properly, although it was "fine when we left the car."
And most recently a gps user could not find enough sats for his unit to give an accurate fix, although I could see there was an eight figure grid reference displayed on the screen!
My humble map and compass does not need a battery, is always reliable, and as long as I retain my mental faculties, will get me home.

John Murphy

  • New Member
  • *
  • Posts: 18
Technology has certainly moved on. However, stupidity has not! On more than one occasion I have been asked to confirm a location or direction for people relying on a phone based nav system.
First case, the battery had run out and it was getting dark.
Next case, the app was not working properly, although it was "fine when we left the car."
And most recently a gps user could not find enough sats for his unit to give an accurate fix, although I could see there was an eight figure grid reference displayed on the screen!
My humble map and compass does not need a battery, is always reliable, and as long as I retain my mental faculties, will get me home.


But that has nothing to to do with the technology! It is human stupidity. That has been the bain for MRT for years and getting worse. Plus with a map and compass if you do not know near enough where you are to start with especially in conditions (whiteouts etc) where you cannot see more than a hundred yards. Taking cross bearings would be impossible to accurately position yourself. Even in clear weather getting it down to 20 yards is good considering.

Owen

  • Veteran Member
  • *****
  • Posts: 1760
... however with regard to the original query, I have to admit that while I have a sighting compass, I've rarely used it.    I have a Suunto Nato compass and also a Recta compass that I bought because it has a declination correction feature, which I have found of rather more use than a sight.   




The problem with any handheld sighting compass is the small size of the bezel (the round bit with the degrees marked on it) it's just too small. Back in the days of the original Victorian ordinance surveyors who made the first maps they used a tripod mounted theodolite with a 9 inch bezel and a sighting telescope.
Getting a bearing from a map is one thing following it over rough ground in zero visibility is another thing; that requires practice.     

rambling oldie

  • Full Member
  • ***
  • Posts: 114

If you always walk on manicured footpaths you won't need a compass. In other parts of the country that's not often possible. Up here in Scotland paths can be very faint or non-existent and visibility is often obscured by thick mist even in summer.


There can also be difficulties in the well populated south.  I walk in Hampshire and two areas popular   with car-borne families and dogs include Alice Holt Forest and Hankley Common (the latter was Scotland in Skyfall and the recent Macbeth)  There are very clearly marked trails, proper footpaths and a lot of other paths that are well trod but go absolutely any'bloody'where!  To follow a pre-planned route prepared on OS Maps can be tricky without careful compass use.  My recent recce for my rambling group went seriously awry (my bad map reading I have to admit) and I may one day go the GPS route.  
It's all good fun though!  

Snowman

  • Sr. Member
  • ****
  • Posts: 435

But that article was written over 10 years ago!Technology has moved on since then. :)  Although I have always used map and compass and gps as a backup as it gives you an accurate position when needed.




Why is the movement of technology over 10 years relevant?    A GPS is still fundamentally the same as it was 20 years ago, an electrical circuit that uses batteries to pick up (US owned) satellites, which was the point that the Scottish MR guy was making.


As previously mentioned, I did a bit of ocean sailing back in the 70's, and by the 80's we were getting electronic navigation aids (Decca originally and of course later, satellite).    However no-one ever went to sea without knowing how to navigate using traditional charts, parallel ruler and compasses, and I would expect (and hope) that they still do.    OK the danger resulting from failure is more acute at sea, however that doesn't negate the possibility of equipment failure on land.


Like you, I do have a GPS for backup, but it doesn't come out of the rucksack very often.




Jim Parkin

  • Full Member
  • ***
  • Posts: 236
Technology has certainly moved on. However, stupidity has not! On more than one occasion I have been asked to confirm a location or direction for people relying on a phone based nav system.
First case, the battery had run out and it was getting dark.
Next case, the app was not working properly, although it was "fine when we left the car."
And most recently a gps user could not find enough sats for his unit to give an accurate fix, although I could see there was an eight figure grid reference displayed on the screen!
My humble map and compass does not need a battery, is always reliable, and as long as I retain my mental faculties, will get me home.

Living about 90 mins walk from kinder Low, I have several times been asked to point out where we are by people with a GPS actually showing where we are.  Usually in good visibility.  What they are actually asking for is to relate the map features to what they see.  I tend to use a GPS for logging my walks. 

As an aside, one of my friends told me that he was on a night hike across Kinder, and had put his compass next to his phone, whereupon it got demagnetised... he spotted this, and used his backup compass.  He had my eldest two kids with him at the time. 

jethro10

  • Full Member
  • ***
  • Posts: 134
Technology has certainly moved on. However, stupidity has not! On more than one occasion I have been asked to confirm a location or direction for people relying on a phone based nav system.


And I've been asked twice this year to confirm a location to two groups using maps and compasses.
Again, stupidity.


jethro10

  • Full Member
  • ***
  • Posts: 134



Why is the movement of technology over 10 years relevant?    A GPS is still fundamentally the same as it was 20 years ago, an electrical circuit that uses batteries to pick up (US owned) satellites, which was the point that the Scottish MR guy was making.


Without taking sides, the improvements are very relevant.
Electronics reliability.
Electronic sensitivity more likely to get a lock
More powerful chips to detect and remove 'noise'
Battery efficiency of the circuits
Longer battery life from the batteries
Systems that use GPS and Glonass for quicker, more reliable and more accurate locks.
All these make it less likely to fail and more likely to get a lock.


Another big one is price. When 3 of us were out walking today. We had 3 phones with maps and the routes on, and 2 of us had dedicated sat nav devices, because we wanted to for convenience and they cost relatively little compared to in the past and with wage inflation. If 5 devices packed in today, I'd more worry about an Alien invasion that taking off my rucksack to dig out a little used map.


This part of the article is very misleading compared to 2017.. Stupidity remains broadly the same however.......


J


Snowman

  • Sr. Member
  • ****
  • Posts: 435
I still don't get the relevance?    What difference does 'more powerful chips ...' make to the comments made by the MR guy?   My old GPS is a Garmin, one of the first handhelds and is significantly older than 10 years.   The only difference I see is that a) it doesn't have a pretty map interface, b) it's bigger (but so what?) c) it uses batteries quite quickly and d) it takes a couple of minutes from turning it on to picking up sufficient satellites to give an accurate position.    With regard to the accuracy, I've never noticed that it wasn't accurate so why should technology that's 20 years older be significantly better?    Batteries?   Great but suppose you forget to replace them before a trip, or you carry replacements but one is a dud?


As to wonderful advances in technology, I've worked with computers for very many years now and have seen sufficient software and hardware failures to prefer not to place my life in their hands.



I also find it interesting that the best way to avoid failure is for everyone in your party to carry at least one GPS receiving device.   Ever go out solo?


Anyway, it was never my intention to resurrect all the old arguments of GPS vs. traditional.    I will sign off on this one by merely stating that my point is that while both navigational methods have a place, I agree completely with the MR guy that an over-reliance on technology carries potential risks.   I pointed out that I have a GPS, although I only use it as a backup.   I pointed out that at sea, that risks associated with reliance on technology are not acceptable - now I'm sure someone has an uncle Bert who pops over to the Channel Islands for his cheap booze but relies on his electronics, however the navigational requirements of the UK's Yachtmaster certification suggest that such risk is not considered 'advisable'.    Just because a Scottish MR representative questioned reliance on technology 10 years ago, that doesn't make it any less relevant today.


Please don't keep up this 'technology is the answer to life, the Universe and everything' argument.   Technology is not failsafe.


Out.








jethro10

  • Full Member
  • ***
  • Posts: 134
I still don't get the relevance?   



Please don't keep up this 'technology is the answer to life, the Universe and everything' argument.   Technology is not failsafe.


Out.


Don't worry, you don't have to get it. Do a bit of research if it interest you.
No I never go solo, you're screwed if something happens. Stupid thing to do to me.


And technology isn't the holy grail, agreed, but it makes most of us live a whole lot longer and more comfortable. I applaud it.

 

Terms of Use     Privacy Policy