How to estimate distance

How can I estimate the distance to an object in the field. I would like to know how to determine distance for long and short distance objects.

I was looking at my map last trip and trying to determine my location by triangulation, but all the peaks in the distance were so far away that they sorta blended and I could not tell what was what. Closer in there was a set of peaks and I could not determine if they were the first set on my map or the second set on my map. This is sort of new to me, but I find it very challenging. I have been googling with the intent of finding some source of info on distance determination, but I can't find much. I did find the online Army field manual and it was pretty cool.

Without a rangefinder of some sort, I doubt you can really determine distance to an object with any accuracy.

I'm no expert, but I believe the key to locating yourself on a map is being able to identify multiple landmarks and using a compass to translate those sight lines to the map.

I notice that the lighting makes a big difference. It must be the shadows. I also think everyone has different depth perception abilities. I do not recall having much trouble with this myslef, if the lighting is right.

If your map is to scale you should be able to get a good idea based on the legend. The legend on the map tells you a certain amount of inches or centimeters equals X amount of miles or kilometers. Where I hike there are groomed trails which are often marked with sign posts and so it isn’t much of an issue. We aren’t encouraged to hike off trail because of the fragile wild plants etc.

Howie

Scale also causes mis-perceptions. If there's nothing near the object for which you know the size (a person, some trees, a building) it's very easy to misjudge size.

For example, I'm sitting in a motel room in Las Vegas (national accounants' conference, no say in the location, and I'm required to attend because I chair our state's committee; my impression so far is that if Nellis AFB needs a new weapons range, I know where they can get one without wasting any perfectly good desert.)

But I digress. As I look out my window, I can see the mountains. There are no trees on the mountain, and no buildings anywhere near; there's also what appears to be a good amount of desert between the edge of town and the beginning of the range. Based on my perceptions and affected by the height of similar-appearing mountains in Tennessee ("similar" meaning how far above the plain they appear), I'd guess these mountains are about 4,000 feet high, and about 10 miles away. However, I'm willing to bet (hey, it IS Vegas) that I'm at least 10,000 feet and at least 40 miles off.

I tend to keep track of how long I have been hiking. I seem to travel about 3 km per hour depending on the difficulty of the terrain. I leave from a set place and after an hour I check and see if my surroundings match with my map. Of course, if I am hiking through the woods I may not be able to see much. However, on a groomed trial I am going to have a pretty good idea where I am anyway. Sure I cannot judge by eye the distance from a mountain, but if that mountain has a name I can use it for a reference along with a river or some other landmark. Of course I have to correctly identify said mountain, and that can be problem <img src="/forums/images/graemlins/smile.gif" alt="" /> It gives a guy something to think about. Keeps one from getting bored. If this was easy, everyone would be doing it <img src="/forums/images/graemlins/smile.gif" alt="" />

Howie

I can do it with my mil-dot scope. Otherwise, I am terrible.

Rootball

This is the root of the compass/GPS thing. Map and compass navigation only allow you to get somewhere from a KNOWN position. If you are lost, a map and compass are almost worthless unless you can SEE some identifiable point. The problem is with viewing angle. You may see a "peak" that isn't really a peak when looking up at it. I have pulled out a map and compass when I KNEW where I was and I could not locate my position on the map using triangulation. I guess the Earthling firestraw can also be used as a straight edge - you have a pencil right? and a protractor?

Without the ability to measure angle to an object, its tough, but if you can get a compass bearing, walk a measured distance "perpendicular" to the object, take another bearing and use a trigonometry table. lets see you would divide the measured distance by the cosine of the included angle, which will be less than one, so the calculated distance will be larger than the measured distance. This will give you the distance to the object from your final position, but only if you made a right angle triangle at the starting point.

jim <img src="/forums/images/graemlins/cool.gif" alt="" />

P.S. I am so sick and tired of hearing people spout off about maps and compass. Lets hear what an expert has to tell us about becoming found when lost with a map and compass - come on - you guys - put up or shut up. <img src="/forums/images/graemlins/tongue.gif" alt="" />

And just whom on this board, or another resource, would you consider an expert?

Perhaps MSN can gather us some input from her SAR buddies.


T

Just how do you suppose soldiers fought wars before GPS was invented? They moved by map and compass. Likely experts at it if they expected to win.

Howie

Yeah Jim, Thats what I'm asking about. I get out map and compass, get everthing oriented and start to look for somehing that I can identify on the map, but it rarely plays out when I test it against other nearby peaks or features. I have always found it interesting to try and use my map. I always carry a freekin map - I might as well get it out and try to use it now again. I know most areas are so well groomed that a backcountry map is used as a road map and not much more. But I do some bushwhackin' and like to be able to use my map even where are no trails to follow. Besides that, its fun and I like it.

Have you thought of using an aviation map?. Hiking shops (around here at least) have more detailed maps also. The forestry people have to have good maps too. I find not all maps are equal.

Howie

Here in New Brunswick when I get lost I make some assumptions and test out those assumptions using a map and compass and watch and counting paces until I get to a backroad or stream or ocean. In the big country out west or up north I would surely die, but here a map and compass and watch work well for me, and are more fun than GPS. Winter is tougher though, with deep snow.

As far as estimating distance to some distant point goes, not being sure where that point is on a map, that's a good question. I haven't had much need to do that. I think your suggestion of pacing sideways and using the change in bearing is a good one. "Six degrees subtends One Tenth of an Arc", so if you paced off 100m and got a change in bearing of 3 degrees, it would be 2 km away. 1 degree would be 6km away, but that would be prone to error. For very distant peaks you would need to do some hiking with some accurate pacing and bearings, and then use a protractor, and you would want a very accurate compass to save a lot of pacing. Kind of gets into surveying and map making the old fashioned way. Fun stuff. Maybe something for measuring angles of inclination also. I could see something like that as a fun hobby for some people. Personally I like to be able to sneak a peek at the answers, so I would still carry a good map. <img src="/forums/images/graemlins/wink.gif" alt="" />

The problem with this is that if you are lost with a map, then you aren't an expert. An expert wouldn't be lost in the first place. I am not an expert. I also have never been lost, so I never needed to be found, (except that time in Yosemite when I was 11, a boy scout, no map, and on a trail that many people hiked on). Maybe I will change my tune when I actually get lost. But then, I wouldn't be an expert. <img src="/forums/images/graemlins/shocked.gif" alt="" /> <img src="/forums/images/graemlins/shocked.gif" alt="" /> <img src="/forums/images/graemlins/grin.gif" alt="" /> <img src="/forums/images/graemlins/grin.gif" alt="" /> <img src="/forums/images/graemlins/grin.gif" alt="" />

I thought I was lost once. The trail left the woods, crossed a wide meadow, and went back into the woods on the other side. There were no blazes, cairns, or signs in the meadow. I consulted the map, got what I thought was the bearing, and set off across the meadow. Got to the other side: no blaze. Walked right about a hundred yards, then left a hundred yards. No blaze. I could feel the panic rising. Luckily, I'd read a book, and it's advice was perfect: when you start to panic, sit down, eat some GORP, and think about things; if you can't figure it out, turn around and head back to known territory. So I sat down under a tree, ate a snack, puzzled things out on the map, and calmed myself down. I had a plan; I stood up to execute it, turned around - and saw the blaze on the tree I'd been leaning against. <img src="/forums/images/graemlins/blush.gif" alt="" />

I never forgot the panic feeling, and realized how it could lead to problems. So, when several of us began teaching others to backpack, we ran a drill that called for each participant to walk about a half mile by themselves (with a map and compass.) The route took them to a trail intersection; they had to decide which way to go. (We stationed a leader about a quarter mile down the right trail, to stop them and get the group back together; another leader was about a quarter mile down the wrong trail, to corral those who chose poorly and take them back to figure out where they went wrong.) This forced them to choose, all alone, and then deal with the panic they invariably felt as a result of being unsure they had taken the correct trail. Better to get them used to the feeling in controlled environment, we felt. It seemed to work.

One of the limitations of a map and compass is that it is very easy to walk off a map's boundaries... in which case all you have is a compass. You really should have a full set of maps of an area, even if you don't "think" you're going to need all of them.

A GPS isn't perfect either... you still need coordinates if you want to get from point A to point B, and a GPS won't tell you if there are impediments in the way (like cliffs/dropoffs, rivers, etc.).

Topo maps give way more information than just a trail. You can get lost with a map and compass, sure, but you can get information from a map that you can't get from a GPS. Map and GPS is a good combo, but you could run out of batteries, drop the GPS, have an electronic malfunction, fail to pick up a sattelite, etc etc etc...

It really is very difficult to judge distance to a landmark in the field, and when you are hiking in heavily wooded areas, you can't triangulate unless you can find 2 very clear landmarks, like radio towers or Fire Observation towers, etc. Trails certainly are not well represented -- location wise -- on topo maps, so you can't rely solely on the direction a trail is actually going versus the direction is it "supposed" to go. The best way to keep from getting lost with a map and compass is to familiarize yourself as much as possible with all information you can gleen about a trail/route/area from topo maps, aerial views (GOOGLE Earth), trail guides, etc. etc.

No magic answers, I'm sorry to say. We usually have Aerial ops to compliment our ground crews.

MNS

The one time that I needed to locate myself on a map and had good success doing so was at Lake Superior Provincial Park on the Coastal Trail. We had been hiking most of the day and were looking to make camp. I kept expecting to come to a river and follow the trail upstream to the campground, but the river just wasn't to be found. I was able to use a couple of islands on the map to triangulate my position and learned that we were about four miles short of where I thought we should be. I determined that we hadn't passed a landmark that I thought we had, and that we should be coming to it very soon. After we resumed hiking we came to that landmark. As it turned out, I had located our position within a few hundred feet and we decided to make camp at an alternate site.

This trail is rather unique, however. It is unusual to have sight lines to such easily identified landmarks in the distance.

Jim,

I do not know what an expert is but I have been orienteering since 1980. Before that I was a navigation instructor in the military.

I keep "in touch" with my map and have never been lost so bad that I could not determine my location within a half hour. My primary navigation is map reading only. I rarely use my compass.

The worst type of error is a parallel error. That is when you are in the drainage, but think you are in a parallel drainage. Linear features like ridges and drainages seldom have the same orientation. Shoot a compass bering on the linear feature and not for a map feature with the same orientation.

I can make up situations where I would need a GPS, but normally I avoid those situations. I have never been caught high in limited visibility with only a narrow safe bail route. I have bailed on trips and will again, but I bail before the situation gets grim. This is supposed to be fun. <img src="/forums/images/graemlins/blush.gif" alt="" />

The military liked to set up navigation problems where you were likely to fail. The lesson was supposed to be that it is safer to dig in and call an artillery strike on your own location that to try to navigate in impossible conditions. <img src="/forums/images/graemlins/shocked.gif" alt="" />

Howie,

The battle of Bunker Hill was actually fought on Breeds Hill. They got a little lost. <img src="/forums/images/graemlins/blush.gif" alt="" />

Again with the compass vs. GPS rivalry??? <img src="/forums/images/graemlins/wink.gif" alt="" /> <img src="/forums/images/graemlins/grin.gif" alt="" />

The point you ignore is that we might as well invert this and say: "GPS only allows you to get TO a KNOWN position." GPS won't help you one whit to determine the distance between you and some mountains in the distance that you may or may not be able to identify, unless you remembered to pre-program a waypoint. (I know some GPS systems have basemaps, etc., but I'm talking about the essential satellite technology here).

GPS, when it works, tells you where you are very precisely. But it delivers this datum in the form of a rather abstract system of imaginary lines that we have plotted on the planet--latitude and longitude. The real problem (assuming you're lost) is, how do I get from here to where I want to be?

Did I remember to turn the unit on and click a waypoint for my car? Do I know how to convert 42.45464587 degrees into minutes and seconds so I can apply it to the tic marks on my map? Did I remember to bring my t-square? <img src="/forums/images/graemlins/wink.gif" alt="" />

I like GPS. It's what I use for navigation (and for fun) most of the time, as long as I have the time and ability to pre-program waypoints. But it's silly to frame this as an either/or choice between GPS and compass. Basic competence with map and compass will remain a valuable skill for any backcountry traveler--especially trip leaders.

You know what instrument will be less common? Altimeters. If you're carrying a GPS and can get a decent signal, the elevation data is usually pretty consistent, in my experience. So long as you brought a decent topo, that information can be quite a bit more relevant than your angle of repose towards Greenwich, England. <img src="/forums/images/graemlins/grin.gif" alt="" />

I am practicing/ training my mind and eyes. Someone on another forum suggest this technique and I think it has merit ....
Go to a known area/ ridge or high trail. Using GPS ''goto'' a known mountain top, tower, ect that you can see. The GPS will tell you what the line of sight distance is. Study the details and train the mind and eyes to work together.
I did this today on a trail back. I was on a high trail on the side of a mountain and got to a fantastic vista where I could see to a mountain top that I have camped on many times. I guessed the distance from where I was and then checked my answer with the GPS. My answer was really close - but of course I know the area. I was exactly 3.25 miles from the object. I made a relation in mind to this number and what I was looking at.

it is my opinion that they should both be used together. the gps will always be able to direct you to your last way point . as you hike the map and compass is used to keep you from getting lost. they really are not that good when you are lost especially in some of the areas i travel in, heavy forest that is very flat for miles.

in this day and age there is no real excuse for not having and being competent with both. some one had mentioned that the army fought the 2nd ww without gps but i guess they dont realize just how much time was actually spent by the army lost. also in the kuwait war one of the biggest problems that came out where the lack of enough gps,s to use in the featureless desert and blowing sand.

buy a gps learn how to use it , carry a map and compass and learn how to use it ,this is very simple thinking to me.

I'll pass. I had one for a while and all it did was hitch a ride in my pack. So I sold it and haven't missed it. The few times I tried to use it I found it annoying to fiddle with.

paddy to me it seems you might be a little bias , can you say that you gave it a real good shot at learning how it worked and used it regularly as you went . also mine is a simple one and does not have alot of extra,s that i do not require.here is an example of why mine is very important to me.

i am hunting north of our town the area is very flat and no mountains or land marks are visable , i wound an animal and it takes off running. the trees are thick and you can not see the sky. withouy my gps and marking the spot where it all began i would not want to bet that i could find my way out. yes you can put up flag tape as you go but as it gets dark will i be able to find it by headlight what if a storm blows in i always know that no matter what i will have a way to get back. yes most definate i would watch my compass as i went but with all the twisting and turning will i be able to retrace that route probally not. this gps gives me peace of mind and it is a good feeling that yes i may get a little twisted up and i probally wont have to set off my p.l.b. and wait sheepishly for the calvery to come when i am only a mile or 2 from my truck. [img][image]http://i297.photobucket.com/albums/mm236/northernbc/DSC00097-1.jpg[/img][/image]

Forgive the language note, but:

It seems to me folks should learn the difference between bias and biased. Moreover, the fact that someone expresses an opinion different than one that you hold doesn't necessarily indicate bias.

thank you and absolutly forgiven you all have been very helpfull. thanks to all your help i can post pictures ,make paragraphs,and kind of use punctuation. i do not use a computer at work and obviously have had no training.

so what was he, biased . i'm a little more familiar with my bias-ply's or whatever they are. cheers lyall

azcanyon - I think I understand your post. Your post indicated that a gps could not tell me the distance to a distant peak, whether known or not. I should have been more detailed in my original post - I want to be able to know line of sight distance, not walking distance. I have been doing exactly that in trying to train my eyes and mind to learn distances. As a matter of fact I was on a ridge trail three weeks ago and came to a beautiful vista. I oriented my map with compass and, having hiked for a long time in the area, identified a distant peak. While the gps was locating sat's, I measured out the utm coords. When gps was ready to navigate I entered the utm coords that I had come up with for Big Fodderstack and then hit 'goto'. The gps told me that I was looking at a peak that was 3 point 2 something miles away. I studied this view for a while - commiting to memory as much detail as possible. Of course it would have been just as easy to do this without the gps and just measure to scale. But why not?

to me when i am out distance and time are very closely related figure on 3 mph and add 1/2 hr for every 100 ft of elevation try to practice looking back when you can to see aprox how far you have travelled in 1 hr this can help you to recognize the aprox distance and time on similar terrain.

Of course I'm biased. I like my opinion better than yours. That's why I have it. <img src="/forums/images/graemlins/grin.gif" alt="" />

well paddy-crow i have been home sick today probally just annoying everyone and that last post actually made me laugh out loud most excellent thank you

I'm glad you took it how it was intended.

I'm trying to maintain a bit of humor despite difficult times. Sometimes when it rains, it pours...

I will admit to be in exactly the same boat as paddy about it <img src="/forums/images/graemlins/smile.gif" alt="" />

There's always a roll of lime green and blaze orange flag tape in my hunting pack for exactly the situation
you describe, and I don't follow a blood trail without. You have a light, you should be able to find the flags.

However you're spot on that the situation you describe is a perfectly good use for a GPS unit. Nothing at
all wrong with that..

you are right about the flagging tape it is essential to carry i was just trying to envision a situation where a gps would work where a map would not.

I tried to look through the tread to see if anyone had mentioned the eye-blinking method, but I did not find it. If it is already mentioned, bear over with me.

The method uses the fact that the distance between the eyes of people is usually 1/10 of the distance of the arm up to the thumb. First you need to spot something that you know the height of at the target. If there is a building, count the number of floors, then you know the height aprox. If there are trees, you know the height usually in that district. For longer distances you must know the height of mountains, just look at the map. (f.ex an island on a lake, find the difference from the water level)

Then you do this: With one eye closed and arm stretced out, raise the thumb up (no not the middle finger <img src="/forums/images/graemlins/grin.gif" alt="" />) and use one eye, then the other. If you keep your hand steady, the finger will point to a different place from one eye to the other. If you know that a tree is say 60 feet high, and the finger "moved" a treelength to the side then the distance there is 600 feet. For greater accuracy use a pointed object, pencil, knife, straw.

I was with some people once and one asked the distance to a house. Several guesses came up. I used my eyeblink-method and said 400 yards. One decided to check by walking and counting steps. He came back a litle later, rather baffled and said it was 405 yards. He had counted his steps both ways. I had luck on that one <img src="/forums/images/graemlins/grin.gif" alt="" />

Cheers back at you. And FWIW, I share your opinion about the usefulness and convenience of GPS vs other methods of navigation/orientation. I just don't want to get rid of the other methods!

Absolutely why not. In fact, the GPS can provide a level of feedback, of detailed confirmation, that you'd never be able to get without it. Your posts here indicate (in my humble opinion, anyway) that you're on the right track. The trick is in being able to connect your real world observations with "map information." And when I say map information, I'm including GPS data, whether in the form of lat/long, waypoints, or programmed basemap.

There's no real shortcut to learning to do what you're learning to do, which is compare the information in your maps (in whatever form) to the things you see and are trying to walk upon.

It all gets rather philosophical and complex, I know. But the "training" you described about comparing your topo to what you're seeing in front of you is the right way to go.

I think that's a really good idea, judging distance using the standard issue Mark I eyeball. By estimating first, and then checking with a map and/or some other means, I think you could get very good at judging distance to objects over time, even with standard issue computer hardware. Mine is actually in exceptional shape. Hardly been used. lol

It is similar to testing your judgement in other areas before confirming with instruments. Time of day. Time and/or distance since you last checked. Air temperature is another good one. Besides training your senses and judgement this might also be a good way to check to see if you are starting to lose it for one reason or another. I don't use a GPS where I hike. If I went someplace else I might carry one as backup. I don't think I will ever use one as my primary means of navigating. I think it would just make the brain go soft. Keeping my brain active performing more natural functions by processing natural information in a natural setting is one of the main reasons I go hiking in the great outdoors. GPS ain't natural. Map and compass and watch and dead reckoning aren't completely natural either, but they are close enough. We don't want to stop thinking in terms of, well just in terms of whether it feels right, and where we might get to by sunset, and what the weather is doing, and how many extra days travel we might have if it snows hard tonight. I think a GPS can take away more information than it provides if you're not careful.

I would definitely carry a GPS in situations I needed it. I make it a point not to I guess. I do use alot of other instruments, like a watch and compass and a thermometer, and even a heart rate monitor, both for more accuracy and as fun learning tools, but for some reason not a GPS. I draw the line there. If I did as much as possible I would only use it for confirmation, to train the brain, but a good crutch can leave you a cripple. Where I hike and for what I do I don't need one. I often bushwack, and almost always make a point of getting lost when I do, but always within a well contained play area. This keeps my brain, well, less dull. I don't use flagging tape either, but I sometimes follow others. If I was out there performing some specific task like hunting it would be different, and then I would use GPS for sure, but I am really only out there to mess around. With a GPS I would have to go farther and deeper for it to be as much fun, and I am not sure it would be.

I've often thought if I ever sailed the world I might do it without too much information or too much instrumentation, to rediscover the world for myself, the old ways. I'm convinced it can be done just as safely. It just takes longer. I wouldn't get as far, but whatever I discovered I could call my own. <img src="/forums/images/graemlins/wink.gif" alt="" />

Have you read about the South Pacific islanders who navigate by their butt? They feel the timing and sequencing of the waves that are constant throughout their area. They used to use this method to help travel hundreds of miles on open sea. Some have kept this lore alive and can still use it. Amazing . . .

That is pretty amazing. I know from sailing small boats, and bigger boats also, you get alot of information from the seat of your pants. Kinesthetic sense is wicked important for sailing, mostly for good boatspeed and good boathandling, but its fascinating that it can be for navigation also. I think kinesthetics is a combination of the entire body dynamics, plus the inner ear. Besides hearing and kinesthetics the ear is also what gives you wind speed and direction, and changes in wind speed and direction. If you cover your ears sailing, or paddling for that matter, its like sailing in the dark. Of course sometimes you have to, especially for paddling, because if you let your head and ears get cold you can lose your sense of balance big time, and judgement. Hats with earflaps are good so you can flap up and flap down. Even when hiking in a cold wind I flap up now and then or take my hat off when I can, probably just out of habit more than anything, to get a better sense of what the wind it doing. That's what thousands of hours of sailing will do to you I guess. I get hit by a wind shift and have to keep myself from tacking or gybing. lol