This topic has been archived, and won't accept reply postings.
Bit of a navigating nerd discussion...
Some navigation instruction manuals discuss techniques for estimating distances visually. Now, whilst I understand how they work, I can't, at the moment, think of many reasons why I might want to, if navigating by map and compass (and you're tracking progress by pacing/timing).
I've seen it suggested that you can distinguish landmarks in this way, but, if you're having to identify landmarks, it suggests you don't know where you are, and so wouldn't know how far it ought to be to each landmark...
If I were exploring an unmapped area, I could use estimated distance and bearings to sketch my own map.
If I'm wandering idly without map & compass, I might estimate distance to see how long it will take me to get somewhere.
Then it struck me that some of the techniques discussed seeing features on a human at different distances, and I wondered if they had a military origin (replace 'distance' with 'range', and 'landmark' with 'target').
Any other suggestions?
Some navigation instruction manuals discuss techniques for estimating distances visually. Now, whilst I understand how they work, I can't, at the moment, think of many reasons why I might want to, if navigating by map and compass (and you're tracking progress by pacing/timing).
I've seen it suggested that you can distinguish landmarks in this way, but, if you're having to identify landmarks, it suggests you don't know where you are, and so wouldn't know how far it ought to be to each landmark...
If I were exploring an unmapped area, I could use estimated distance and bearings to sketch my own map.
If I'm wandering idly without map & compass, I might estimate distance to see how long it will take me to get somewhere.
Then it struck me that some of the techniques discussed seeing features on a human at different distances, and I wondered if they had a military origin (replace 'distance' with 'range', and 'landmark' with 'target').
Any other suggestions?
In reply to captain paranoia:
Suppose it depends on what scale you are estimating over.
It's not unusual to have a good idea roughly where you are (ie what end of a valley), but to need to narrow down your location more precisely as you get near to a critical point in the route. One way to do that is obviously to look around at the major landmarks and use those.
The ability to estimate distance can help here. For instance, identifying that a particular peak is likely 5km rather than 1km away, or that you are 400m rather than 800m away from a ridgeline, can be quite handy.
Suppose it depends on what scale you are estimating over.
It's not unusual to have a good idea roughly where you are (ie what end of a valley), but to need to narrow down your location more precisely as you get near to a critical point in the route. One way to do that is obviously to look around at the major landmarks and use those.
The ability to estimate distance can help here. For instance, identifying that a particular peak is likely 5km rather than 1km away, or that you are 400m rather than 800m away from a ridgeline, can be quite handy.
In reply to captain paranoia:
You're right, it is an important basic military skill because it tells you can I shoot him, can he shoot me, where should I aim, how do I set my sights etc etc
Having said that, I use it frequently for nav too. Just to confirm things really. Say I'm at a known point,looking for a feature and I think I can see it on the ground but I'm not 100%. Does my visual estimate of it's distance from me agree with the distance on the map? If it does, good. If it doesn't check everything again. It's just one more piece of the puzzle. Obviously you can check with pacings in this way but it's quite time consuming and laborious, you don't want to do it any more than you have to imo.
You're right, it is an important basic military skill because it tells you can I shoot him, can he shoot me, where should I aim, how do I set my sights etc etc
Having said that, I use it frequently for nav too. Just to confirm things really. Say I'm at a known point,looking for a feature and I think I can see it on the ground but I'm not 100%. Does my visual estimate of it's distance from me agree with the distance on the map? If it does, good. If it doesn't check everything again. It's just one more piece of the puzzle. Obviously you can check with pacings in this way but it's quite time consuming and laborious, you don't want to do it any more than you have to imo.
In reply to hamsforlegs:
Similarly, if you're looking for features to relocate yourself with then the ability to judge how wide the gap between two things is - ridges, tributary streams etc - can be rather handy.
Also I guess that having a good sense for estimating distances by eye feeds into good general awareness of that sort of thing, which in turn is useful for having a feel for how far you've gone in bad visibility or whatever.
Similarly, if you're looking for features to relocate yourself with then the ability to judge how wide the gap between two things is - ridges, tributary streams etc - can be rather handy.
Also I guess that having a good sense for estimating distances by eye feeds into good general awareness of that sort of thing, which in turn is useful for having a feel for how far you've gone in bad visibility or whatever.
In reply to captain paranoia:
Thanks for the replies; they seem to tally with other (unexpressed thoughts) that it's a useful confirmatory skill, and good to have a general sense of how far away things are, as general 'situational awareness' feel of where you are, a bit like having an idea what the terrain should be like from the contours.
I've been trying to think how I use it for navigation, and I suspect that I do judge distances, and assess how long it ought to take to get there, and know roughly when I ought to be there ('not there yet', 'have we gone too far?', without doing any formal pacing or timing; the sort of subconscious stuff you end up 'just doing'.
It doesn't seem to be used for a specific navigation technique (like resection with bearings, for instance).
My ponderings about the military origins were more about how the technique came to feature in a navigation manual, not the actual uses by the military; they're fairly clear...
Thanks for the replies; they seem to tally with other (unexpressed thoughts) that it's a useful confirmatory skill, and good to have a general sense of how far away things are, as general 'situational awareness' feel of where you are, a bit like having an idea what the terrain should be like from the contours.
I've been trying to think how I use it for navigation, and I suspect that I do judge distances, and assess how long it ought to take to get there, and know roughly when I ought to be there ('not there yet', 'have we gone too far?', without doing any formal pacing or timing; the sort of subconscious stuff you end up 'just doing'.
It doesn't seem to be used for a specific navigation technique (like resection with bearings, for instance).
My ponderings about the military origins were more about how the technique came to feature in a navigation manual, not the actual uses by the military; they're fairly clear...
Post edited at 14:02
In reply to captain paranoia:
Because you can use them to confirm where you are?
Most people don't just rely on a single technique for knowing where they are, but combine all sorts of information to locate themselves and then to confirm this.
If you are in a location and can see somewhere that tempts you to extend your walk, or that looks interesting, it can help you decide if you want to alter your plans or not.
General interest?
Because you can use them to confirm where you are?
Most people don't just rely on a single technique for knowing where they are, but combine all sorts of information to locate themselves and then to confirm this.
If you are in a location and can see somewhere that tempts you to extend your walk, or that looks interesting, it can help you decide if you want to alter your plans or not.
General interest?
In reply to captain paranoia:
Slight hijack being as some nav geeks may read this thread:
How for on the ground on a 1 in 25K map is 1mm and 1cm?
Slight hijack being as some nav geeks may read this thread:
How for on the ground on a 1 in 25K map is 1mm and 1cm?
In reply to wilkie14c:
??
Use the scale.
1mm on the map is 25000mm on the ground.
Your compass might even have the numbers printed on the ruler for you?
??
Use the scale.
1mm on the map is 25000mm on the ground.
Your compass might even have the numbers printed on the ruler for you?
In reply to captain paranoia:
You're coming at it from the perspective of one that is used to navigating on paths or has lots of features around. If you're somewhere fairly featureless, then it becomes pretty useful.
You're right about the military link. I used to work for military survey (which gave birth to the OS and wrote those manuals for the British army). Soldiers have a strong impetus to measure distance to set their sights correctly, I suspect an over emphasis on that may have leaked through.
You're coming at it from the perspective of one that is used to navigating on paths or has lots of features around. If you're somewhere fairly featureless, then it becomes pretty useful.
You're right about the military link. I used to work for military survey (which gave birth to the OS and wrote those manuals for the British army). Soldiers have a strong impetus to measure distance to set their sights correctly, I suspect an over emphasis on that may have leaked through.
Post edited at 15:46
In reply to wilkie14c:
Kind of relates back to the op actually, I find it handy to be able to visualise 100m on the ground and to know that it is 4mm on the map.
Kind of relates back to the op actually, I find it handy to be able to visualise 100m on the ground and to know that it is 4mm on the map.
In reply to captain paranoia:
I've been reading Ultimate Navigation by Lyle Brotherton and a lot of the techniques discussed in the book I have never used and probably never will.
I've been reading Ultimate Navigation by Lyle Brotherton and a lot of the techniques discussed in the book I have never used and probably never will.
In reply to wilkie14c:
Not wanting to come across as a "Nav-Geek", but....
1 in 25k is an angle of slope, all be it a very shallow slope.
What I think you meant was 1 to 25k 1:25k), which is a description of scale.
;~))
> Slight hijack being as some nav geeks may read this thread:
> How far on the ground on a 1 in 25K map is 1mm and 1cm?
Not wanting to come across as a "Nav-Geek", but....
1 in 25k is an angle of slope, all be it a very shallow slope.
What I think you meant was 1 to 25k 1:25k), which is a description of scale.
;~))
In reply to captain paranoia:
I would suggest that all UK based navigation is a result of Military 'Thinking' We have good maps (compared to many other places) and teach navigation the way we do because of this. The Alps and such places come from a guiding tradition, hence waymarked trails etc, It tends to be more route finding than navigation as such.
I would suggest that all UK based navigation is a result of Military 'Thinking' We have good maps (compared to many other places) and teach navigation the way we do because of this. The Alps and such places come from a guiding tradition, hence waymarked trails etc, It tends to be more route finding than navigation as such.
In reply to higherclimbingwales:
Yes, good old General Roy. To mark the 250th anniversary, I remeasured his fundamental baseline which kicked off the first triangulation of the UK and went for 5 miles across Hounslow Heath (now Heathrow airport), marked by 2 upturned cannons. He used glass rods, I used GPS. He was 4 inches out!
> The ordnance survey was a military body hence the name - ordnance.
Yes, good old General Roy. To mark the 250th anniversary, I remeasured his fundamental baseline which kicked off the first triangulation of the UK and went for 5 miles across Hounslow Heath (now Heathrow airport), marked by 2 upturned cannons. He used glass rods, I used GPS. He was 4 inches out!
In reply to captain paranoia:
I think we all do this all the time without realising it. You're on a route and have looked at the map and don't want to be a novice and stop to look at the map every two minutes. You've studied the map and have an idea in your head of what you should see on your route but not exactly on your route. The river junction should be 100m to your right, the steepening on the contours should be 400m after the junction, the small cliffedge should be less than fifty metres to your left. As you go along you instinctively look at these things, if they seem in the right place (based on your estimation of distance), you don't even notice you've done it, so you just carry on safe in the knowledge you've got it right. But suddenly the cliff edge is visible 400m away, or the river junction is right at your feet - you're not where you thought you would be. We all do this all the time.
I think we all do this all the time without realising it. You're on a route and have looked at the map and don't want to be a novice and stop to look at the map every two minutes. You've studied the map and have an idea in your head of what you should see on your route but not exactly on your route. The river junction should be 100m to your right, the steepening on the contours should be 400m after the junction, the small cliffedge should be less than fifty metres to your left. As you go along you instinctively look at these things, if they seem in the right place (based on your estimation of distance), you don't even notice you've done it, so you just carry on safe in the knowledge you've got it right. But suddenly the cliff edge is visible 400m away, or the river junction is right at your feet - you're not where you thought you would be. We all do this all the time.
In reply to tlm:
I think I've figured out how I subconsciously use distance estimation, but I'd be interested in the technique you use to confirm where you are.
I agree that we fuse various methods to locate ourselves, but navigation manuals usually concentrate on explaining procedural methods; things we can do with measured values. They rarely discuss the subconscious things we do.
> Because you can use them to confirm where you are?
I think I've figured out how I subconsciously use distance estimation, but I'd be interested in the technique you use to confirm where you are.
I agree that we fuse various methods to locate ourselves, but navigation manuals usually concentrate on explaining procedural methods; things we can do with measured values. They rarely discuss the subconscious things we do.
In reply to Jonny2vests:
As for tlm, I'd be interested to hear the technique you use to apply estimated distance.
As I said, I'm beginning to get how I use it, and I'd like to hear how other people use it, too.
I'd also like to hear of any explicit, procedural techniques for using estimated distance to aid location (e.g. like resection using bearings).
The author of one manual mentioned here has confirmed that the distance estimation methods come from a military perspective, but also have application in search & rescue (estimating location of casualty to search teams); essentially the same purpose.
> If you're somewhere fairly featureless, then it becomes pretty useful.
As for tlm, I'd be interested to hear the technique you use to apply estimated distance.
As I said, I'm beginning to get how I use it, and I'd like to hear how other people use it, too.
I'd also like to hear of any explicit, procedural techniques for using estimated distance to aid location (e.g. like resection using bearings).
The author of one manual mentioned here has confirmed that the distance estimation methods come from a military perspective, but also have application in search & rescue (estimating location of casualty to search teams); essentially the same purpose.
In reply to captain paranoia:
So that you can fit the landscape to the map. The vast majority of navigation is about precisely that and has nothing at all to do with compass use.
So that you can fit the landscape to the map. The vast majority of navigation is about precisely that and has nothing at all to do with compass use.
In reply to Robert Durran:
Unless you have near zero visibility, then navigation becomes all about compass use!
Unless you have near zero visibility, then navigation becomes all about compass use!
In reply to Al Evans:
Indeed, in poor visibility having an estimate of your speed and how far things are becomes more critical. Not that I've ever started descending into the wrong valley, oh no.
Indeed, in poor visibility having an estimate of your speed and how far things are becomes more critical. Not that I've ever started descending into the wrong valley, oh no.
In reply to captain paranoia:
I seem to remember all sorts of techniques that generally took a lot of practise. If you knew the length of a football pitch, you could count how many there were to a target. Then just knowing what say a person looks like at 300m. You had to adjust for staring into sunlight and things like that, which foreshorten estimations.
I remember a pacing and compass technique for estimating gap distances across rivers, so you knew how much bridge to order, something to do with constructing a 3,4,5 triangle. If you have a decent map of course, then you were sorted. And there were all kinds of techniques using binocular graticules and angle subtension.
I seem to remember all sorts of techniques that generally took a lot of practise. If you knew the length of a football pitch, you could count how many there were to a target. Then just knowing what say a person looks like at 300m. You had to adjust for staring into sunlight and things like that, which foreshorten estimations.
I remember a pacing and compass technique for estimating gap distances across rivers, so you knew how much bridge to order, something to do with constructing a 3,4,5 triangle. If you have a decent map of course, then you were sorted. And there were all kinds of techniques using binocular graticules and angle subtension.
In reply to Al Evans:
Or if the map you're using is essentially a blank sheet of paper, people tend to be so UK centric in these discussions.
For me, 'navigation' is something you do when you can't map read (relate map and ground). I used to teach land navigation (things like dead reckoning and basic astronomy), for which the downright luxury of being able to map read when applicable, was a pre-requisite, and taken for granted.
Navigation begins when map reading ends.
> Unless you have near zero visibility, then navigation becomes all about compass use!
Or if the map you're using is essentially a blank sheet of paper, people tend to be so UK centric in these discussions.
For me, 'navigation' is something you do when you can't map read (relate map and ground). I used to teach land navigation (things like dead reckoning and basic astronomy), for which the downright luxury of being able to map read when applicable, was a pre-requisite, and taken for granted.
Navigation begins when map reading ends.
In reply to Jonny2vests:
Absolutely correct, people mistake map reading for navigation far too often.
Absolutely correct, people mistake map reading for navigation far too often.
In reply to Robert Durran:
As above, could you elucidate the technique you use, please?
BTW, despite how it might appear from the question, I'm not a novice navigator*, but I navigate using a bunch of techniques I've invented for myself over the years, many of which are standard techniques (and generally, I use terrain association in upland areas, and feature association in lowland areas, and rarely resort to compass and pacing/timing).
My interest in finding 'formal' descriptions of techniques comes from reading up on 'proper ways of navigation' to help teach DofE groups. And, in that reading, I've found a number of distance measurement techniques described, but then not used in a overt/procedural navigation technique.
* for my sins, I've ended up as an administrator on the micronavigation forum...
> So that you can fit the landscape to the map.
As above, could you elucidate the technique you use, please?
BTW, despite how it might appear from the question, I'm not a novice navigator*, but I navigate using a bunch of techniques I've invented for myself over the years, many of which are standard techniques (and generally, I use terrain association in upland areas, and feature association in lowland areas, and rarely resort to compass and pacing/timing).
My interest in finding 'formal' descriptions of techniques comes from reading up on 'proper ways of navigation' to help teach DofE groups. And, in that reading, I've found a number of distance measurement techniques described, but then not used in a overt/procedural navigation technique.
* for my sins, I've ended up as an administrator on the micronavigation forum...
In reply to Jonny2vests:
Thanks for the reply, Jonny; it's not the technique for estimating distance I'm interested in; those are well documented in the manuals, and exploit basic geometry and visual acuity.
What I'm interested in is how you then apply that distance estimation to assist in navigation; how do you use the estimate to locate yourself, or confirm your location?
Thanks for the reply, Jonny; it's not the technique for estimating distance I'm interested in; those are well documented in the manuals, and exploit basic geometry and visual acuity.
What I'm interested in is how you then apply that distance estimation to assist in navigation; how do you use the estimate to locate yourself, or confirm your location?
In reply to nickinscottishmountains:
I think you're right; we do an awful lot of comparison subconsciously. Somehow, our brain reads the map, and is able to compare what the map says with what the ground in front of us looks like, and track our way through it.
I guess I'm really trying to figure out just what it is we do, so that maybe I can kick-start the learning process. Subconscious processing usually requires a lot of experience before it becomes subconscious...
> I think we all do this all the time without realising it.
I think you're right; we do an awful lot of comparison subconsciously. Somehow, our brain reads the map, and is able to compare what the map says with what the ground in front of us looks like, and track our way through it.
I guess I'm really trying to figure out just what it is we do, so that maybe I can kick-start the learning process. Subconscious processing usually requires a lot of experience before it becomes subconscious...
In reply to Jonny2vests:
The most obvious technique would use a 45 degree triangle; pick a prominent landmark on the far bank, and take a bearing when looking directly across the river. Then walk along the river bank until the bearing to the landmark has changed by 45 degrees. The river width is the same distance as you have walked down the bank (assuming the river is straight...). This is the same technique as can be used to measure the height of a tree, only applied in a different geometric plane...
> I remember a pacing and compass technique for estimating gap distances across rivers, so you knew how much bridge to order, something to do with constructing a 3,4,5 triangle.
The most obvious technique would use a 45 degree triangle; pick a prominent landmark on the far bank, and take a bearing when looking directly across the river. Then walk along the river bank until the bearing to the landmark has changed by 45 degrees. The river width is the same distance as you have walked down the bank (assuming the river is straight...). This is the same technique as can be used to measure the height of a tree, only applied in a different geometric plane...
In reply to captain paranoia:
So you want a technique that will aid teaching how to relate map and ground? Well you could sit in a classroom creating contour profiles or discussing how some clever acronym might describe the techniques one might apply, but in the end its an experience based skill. You just can't beat sitting on a viewpoint or walking along a ridge, making up simple exercises and just doing it.
> As above, could you elucidate the technique you use, please?
So you want a technique that will aid teaching how to relate map and ground? Well you could sit in a classroom creating contour profiles or discussing how some clever acronym might describe the techniques one might apply, but in the end its an experience based skill. You just can't beat sitting on a viewpoint or walking along a ridge, making up simple exercises and just doing it.
In reply to captain paranoia:
Oh I see. I don't think you can easily pin scenarios to it, as you say, its a bit of a throwback to the military origins of navigation, and I imagine it gets used in an almost subconscious sense. There is of course trilateration, which is like a resection with distances, but you'd have to be pretty desperate to resort to that.
> Thanks for the reply, Jonny; it's not the technique for estimating distance I'm interested in; those are well documented in the manuals, and exploit basic geometry and visual acuity.
> What I'm interested in is how you then apply that distance estimation to assist in navigation; how do you use the estimate to locate yourself, or confirm your location?
Oh I see. I don't think you can easily pin scenarios to it, as you say, its a bit of a throwback to the military origins of navigation, and I imagine it gets used in an almost subconscious sense. There is of course trilateration, which is like a resection with distances, but you'd have to be pretty desperate to resort to that.
In reply to Jonny2vests:
Yeah; GPS and Loran are good at that, but drawing circles on maps isn't my idea of fun...
However, I suspect that it's just what our brains are doing...
I've been trying not to say that, as I didn't want to influence people's thinking...
> There is of course trilateration, which is like a resection with distances, but you'd have to be pretty desperate to resort to that.
Yeah; GPS and Loran are good at that, but drawing circles on maps isn't my idea of fun...
However, I suspect that it's just what our brains are doing...
I've been trying not to say that, as I didn't want to influence people's thinking...
In reply to captain paranoia:
Something that might be of interest is "resolvable distance"(taken from Gordon Brown's "Sea Kayak"):
100m: can identify people by facial recognition
200m: can make out faces and colours of clothing
500m: can identify people by movement and mannerisms, small buoys are visible, paddle blades visible
1km: people are dots,can count individual windows on houses, large buoys can be seen
1.5km: can count individual trees, can see "paddle flash"
2km: can count individual houses, distinguish cars from bigger vehicles, almost at limit of kayak to kayak visibility
3km: limit of kayak to kayak visibility, may see "paddle flash", can separate trees from other greenery
Something that might be of interest is "resolvable distance"(taken from Gordon Brown's "Sea Kayak"):
100m: can identify people by facial recognition
200m: can make out faces and colours of clothing
500m: can identify people by movement and mannerisms, small buoys are visible, paddle blades visible
1km: people are dots,can count individual windows on houses, large buoys can be seen
1.5km: can count individual trees, can see "paddle flash"
2km: can count individual houses, distinguish cars from bigger vehicles, almost at limit of kayak to kayak visibility
3km: limit of kayak to kayak visibility, may see "paddle flash", can separate trees from other greenery
In reply to Al Evans:
I suppose it comes down to definitions, but I have always looked on map reading (in particular relating the map to the ground) as the most basic and most frequently used skill of navigation. I probably use a compass a handful of time per year, but I am navigating all the time every time I am out in the hills.
> Absolutely correct, people mistake map reading for navigation far too often.
I suppose it comes down to definitions, but I have always looked on map reading (in particular relating the map to the ground) as the most basic and most frequently used skill of navigation. I probably use a compass a handful of time per year, but I am navigating all the time every time I am out in the hills.
This topic has been archived, and won't accept reply postings.
Elsewhere on the site
Loading Notifications...