View Full Version : Land navigation

09-18-2010, 09:48 AM
Quick Land Navigation Primer copyright 2005 Robert Henry

Grab your compass and a topographical map.

Ready? O.K. let's do a basic exercise in Map and compass.

I'll assume that you know the basic symbols and colors on a topographic map- green means vegetations (woods, pasture, etc.), brown is generally used in contour lines, blue is water or marsh, black is generally used for manmade items such as roads, houses, etc.

On the bottom of the map will be a whole lot of information that is helpful to you. Let's start by figuring out what scale the map is. This will be notated in a ratio such as 1:50,000 which means 1 inch on the map equals 50,000 feet on the ground. Common scale sizes for topographic maps also include 1:24,000 scale which I prefer. The smaller scale maps, such as the 1:24,000 scale will show you more detail than the larger scale maps. The downside is that if you have a large area of operations, you may need to carry two maps. For our purposes, I think it's important to have the higher amount of detail that's available on the 1:24,000 maps. You'll have to decide for yourself.

I highly recommend that you cover all your maps with a clear plastic covering. Office supply stores have this available fairly cheap. It helps protect the map against moisture and also gives you a surface to make temporary notations on with a dry erase marker.

It might be a good time to say that you should never make any permanent notations on the map regarding routes, caches, rally points, location of your retreat, etc. Heck, just the way you fold the map tells a lot of information.

So let's look how we would plan travel on the map.

First things first, let's get the map and compass "on the same page" sort of speak.

There are three Norths, Grid North which is North on a map, Magnetic North which is North that your compass points to, and True North which is the North pole. We will only concern ourselves with Grid North and Magnetic North. Unless you plan on buggin out to the North pole, True north shouldn't have a lot of meaning to you.

We will start by laying our map out on the ground. North on a map is generally up. The legend on the bottom of the map will show an arrow for grid North also.

Next, take your compass out and find North on your compass (magnetic North). Rotate your map until North on the map (Grid North) is the same as North on your compass. The easiest way to show people how to do this is to lay the straightedge of the compass on one of the North-South lines on the map, then rotate until the compass reads North. Double check that the compass is still following the north-south line.

Back to the bottom of the map. We need to find the G-M angle. In some areas this won't be much of an issue, in other areas it will, it's always important to check the map though. At the bottom of the map you will see a small angle that shows Grid North and Magnetic North. This angle will have a notation such as "+1 degree" This angle refers to the difference between Grid and magnetic North (G-M angle). Often times, it is so small you do not have to worry about it. If it's more than 1/2 a degree, I usually factor it in, unless the trip is a very short one.

O.K., so the map and compass are both "on the same page" or orientated. Every time you work with a map, this ought to be the first thing you do.

Now, pick a point on the map, any point. If you got it covered in plastic, mark that point with your dry erase marker. We will call that Point A. Pick another point on the map, a distance away from Point A. Mark that, we will call that one Point B.

Using the straightedge on your compass, draw a line between Point A and Point B.

If your map is still orientated (doesn't hurt to double check), you can figure out how you would get from Point A to Point B simply by lining your compass up on the line you drew. Let's say it's 60 degrees. That's your compass bearing, or azimuth. That's the direction you would need to walk on the ground to get from Point A to Point B.

OOPS! Did we forget the G-M angle? The G-M angle told us to ADD one degree, so now our azimuth is 61 degrees.

So, if we were at Point A and wanted to walk to Point B, the compass bearing of 61 degrees would get us there.

But how far is it?

Knowing the distance is important for many factors, including what to carry, how long the trip will take, etc.

Go back to the bottom of the map and you will find a distance line. Using the straightedge of your compass again, measure the distance of the line you drew between Point A and Point B and find the distance on the distance line on the bottom of the map. That's how far you have to travel to get to Point B from Point A.

Now you have a compass bearing and a distance. Now you can travel from Point A to Point B. Simple enough?

In the future we will look at how to find our position on the map when we don't know where we are.

All for now, as always, I hope this information helped you. Till next time.

Matt In Oklahoma
09-18-2010, 05:54 PM
If you have never doen this do not wait till "the moment" to try it. Like most things ya gotta get out and do it and work your way through the learning curve!

09-18-2010, 09:56 PM
A very good basic start. An easier way of dealing with the differnce between grid & magnetic north is to buy a compass that is mechinically adjustable for declination, such as the Siva Ranger 14 and others. Once the declination is set you don't need to orient the map to determine bearings. Like a lot of things there is more than one way to skin a cat.

09-18-2010, 10:08 PM
Dug my GTA 5-2-12 circa 1981....now i just need to get me some maps for my area. Been a long time since I did some REAL map reading.

09-18-2010, 11:48 PM
Correct. Down here it is less than 1 degree so we rarely factor it in.

09-19-2010, 10:26 AM
Using the map and compass would be an excellent VIDEO!!!! Thanks.

09-19-2010, 12:15 PM
For some good basic info & to find out what the declination is for your zipcode visit www.compassstore.com. For hands-on help check for an orienteering club or a search and rescue group.

09-20-2010, 08:39 PM
Land navigation? Compass? Maps? I've got a GPS, what could go wrong? :p Just kidding.

Great post Lowdown3, basic land nav is something people tend to overlook. Even here in the army I've seen people that are clueless about it. Like everything else, you learn best by doing. Pace count, intersection, resection and everything else covered in the post would make a great video series I think. Take care.

01-22-2011, 12:11 AM
Map Compass 101
Let's look at the most basic uses of a map style compass and how to use it for simple navigation in the wilderness.


Map & Compass 201: Declination
Let's discuss declination. Remember: Declination East: Compass Least. Declination West: Compass Best. I will discuss this principle and how to put it to use to help you become more accurate and more successful using your map and compass. This is a continuation of Map & Compass 101. For your local declination:www.ngdc.noaa.gov/geomagmode*ls/struts/calcDeclination


source of videos

01-23-2011, 09:15 AM
These are excellent videos!. I have seen them about 2 years ago, but re-watching them refreshed my memory. PakRat makes great videos.

Matt In Oklahoma
01-23-2011, 09:32 AM
The other day between a topo map recon of my new place and driving around I located a large set of powerlines about 700yds north of my place that runs about 20+ miles to within a short distance from my work (I was actually looking for secondary water sources). Depending on the event that would cause me to be on foot this may be a great option that will take the guesswork outta the land nav and I even will be able to follow them at night without light and compass. It appears that they keep it fairly clear of brush.

01-23-2011, 09:45 AM
I read somewhere that all DirectTV dishes point in a Southwesterly direction. Good to know if you're lost without a compass or landmark.

Matt In Oklahoma
01-23-2011, 10:02 AM
@monkeybird Ok you should be proud of yourself you made me go out in the cold LOL
I have dishnetwork and it sure enough it points SW

01-23-2011, 10:56 AM
Up here I often use and indeed need an altimeter. If you'll look closly at the 7 1/2 minute maps you'll see real quick that there are some that have 40 foot contour intervals and some that 80 foot contour intervals. Knowing your pacecount with and without a pack on and having Ranger beads or some other method of documenting your time/progress will be a big help too.

08-23-2013, 10:05 AM
So anyone looked at USGS to buy their maps from? $8-$15 plus a $5 handling fee and it can take a couple of weeks. You can download the PDF for FREE and then send it to Office Depot and they will print it out for you for about $20.


If you have access to a Plotter Printer like I do you can print them out yourself. See my map I printed yesterday. I need to refold it correctly so don't beat me up on that.


Not sure if you can see it but there is a light blue color around the map this is the actual map border that was scanned. The plotter I used has a 36" roll so there is some extra white space that i can cut off.

I need to get a map case and of course a quality compass. Any other suggestions?

I just measured the length of the map 27.75" x 22.5"...Does anyone know what the actual map dimensions should be? I may need to tweak the printer options to make sure I have an accurate print.

I just checked the States Geo site and it lists the map as 27 x 22 so I think I am pretty close. They are much cheaper from the state vs the fed. $9 total to have them shipped to me.

Matt In Oklahoma
08-23-2013, 03:50 PM
I get maps from them as well. The map case and quality compass, do you have any friends in the military?

08-26-2013, 09:21 AM
I get maps from them as well. The map case and quality compass, do you have any friends in the military?

All my friends are out of the military unfortunately...i wish i would have stayed in too...this year would be 20 for me...oh well.

I will check the local Surplus and see if they have any map cases...Compass will have to be a Camenga.

Matt In Oklahoma
08-26-2013, 04:01 PM
Try them then
I have not used any of their stuff except the grid overlays