Orienteering 101 – Understanding the Topographic Map

The topographic map is a wonderful invention full of useful information once you learn how to read one.  They come in different shapes, sizes, and scales, but they all share certain conventions that make it easy to pick up a map from different manufacturers and read them without a problem.

They are used by the military, surveyors, and anybody who has the need of knowing where they are and where they’re going.  If you plan on doing a back country hiking trip, a canoe trip, or anything in the woods or wild it would be foolhardy to leave without one of these in your pack even if you’re carrying the latest and greatest GPS.

A topographic map is simply a two dimensional representation of the Earth; however, the way it’s drawn represents three dimensions, which is handy if you want to know how high a mountain or how deep a valley is.  There are some colors that represent various features on a map.  These can change a little from map to map, but these are the basics:

Black – man made features.  Names on the map, elevations, buildings, rail systems, transmission lines, etc.

Red – Paved roads, highway numbers.

Brown – contour lines, elevations.

Blue – water.  Lakes, ponds, streams, etc.  Also swamps and marshes.

Green – wooded areas, orchards, vineyards.

White - some maps will show white patches, which are unforested areas such as grasslands.

Depending on who put the map out there may be other colors as well, but these are the majority.

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Legend

There are also many symbols on a map and most maps have a key or legend telling what the various icons on the map stand for.  It’s best to consult the map you’re reading so you’ll know what the symbol refers to.  The above Legend is for a hiking trail map put out by National Geographic.  I won’t go into the markings here too much, but if you have questions about the map you have in front of you try doing a Google search to find out what the symbols are for.

Another important section of the map is the Scale.  This will tell you how far one inch or one centimeter is on a map.  When you’re plotting a route it’s important to figure out the distance you’ll be traveling over land as accurately as possible.

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Scale

When I looked at the scale above I was confused for a minute by the scale.  1:63360 is kind of an odd number.  After a minute of thinking about it I realized that the answer is right next to it.  1 inch = 1 mile.  This map is designed to be read in miles and not the metric system like I’m used to, which is why it confused me for a second.  Remember that I said 1: 63360 really means that 1 inch on the map equals 63360 inches over land?  Well if you divide 63360 by 12 you get 5280, which is the number of feet in a mile.

The NatGeo map I’ve been referencing so far is a very nice map.  The paper is heavy and the detail on the map is excellent for the scale, plus it has grid squares, which makes lining the protractor up pretty easy.

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I prefer the 1:24,000 map because it gives a lot more detail. On the flip side it doesn’t cover as much territory as one like the 1:63360 maps.

Luckily they also put the metric scale in there as well, which is what I use because I’ve measured my pace count in meters.

Contour Lines

Another important piece of information you should find somewhere on your map is the contour interval.  This is the distance between each contour line on the map unless otherwise noted.  This map has the contour interval at 50 feet.  Other maps have contour intervals of 20 feet, so be sure to study your map closely.

But what are contour lines exactly?  This is one of the features of a topographic map that make it such a powerful tool.  Contour lines are simply lines on a map of even elevation.  Thus, if I stood on a hill and took a piece of string and walked all along a height of 873 feet laying out the string as I went until I got back to where the string started, that would be a contour line.  Using the map above if I walk uphill until  my elevation was 50 feet higher there would be another contour line.

This doesn’t mean that I walk 50 feet, it means that I’ve risen 50 feet in height.  I might have to walk 100 yards to gain 50 feet in elevation.  Conversely, I might only have to move 20 horizontal feet to gain 50 feet in elevation.

Question:  is it possible to not move on a horizontal axis at all and still gain or lose 50 feet?

Answer:  yes, it’s called a cliff.

 If you’re looking at a map and there are big looping contour lines spaced far apart you’re looking at fairly flat land.  If you’re looking at a point on the map where the contour lines are very close together you’re probably looking at a mountain or a deep hole.

As you’re looking at contour lines you’ll notice that about every fifth line has a number associated with it.  These are called index lines.

Thus, if you’re planning to hike through unknown territory if you can get your hands on a topographic map you’ll have a much better idea of what you’ll be walking over.  If you’re studying a regular road map you might never know that part of the route you’re looking at is over a mountain, whereas one look at a topographic map would show that you’re in for a big elevation change in a very short distance.

 

mapexplained2 United States Department of Commerce Coast and Geodetic Survey

 

In the map above I’ve outlined a few of the terrain features you might see on a map.  Near the lower right portion you can see a hill top labeled 910.  This means the hill top is at an elevation 910 feet.  You can see that it looks like a small circle with another line circling it and so forth.  Each line represents a rise of 20 feet as you can see from the scale below where it says Contour Interval:  20 Feet.

scale1-24k

 

Near the middle top of the map I’ve labeled a terrain feature “Very Steep Terrain.”  You can see how the contour lines run pretty close together meaning it’s quite steep.  If you saw a bunch of lines all converge into one line that means there’s a cliff at that location.

Look the example above over and you can I’ve pointed out a trail, valley, hill top, building, index lines and some other things.  With this information you can now start to get an idea of what your terrain looks like.

If I were standing on the road exactly where the arrow points from the word “Road” in the map above and I was facing due north (up) what do you suppose I’d see?

If I looked left I probably wouldn’t be able to see the lake because I’ve got a spur of the hill coming down from behind me blocking my view.  I’d see a hill with trees with the hill tapering off.  If I looked right I’d see an open field in the foreground and then a hill rising into a mountain – all tree covered.  Looking due north I’d see an open field in front of me rising into a smaller hill than what’s to my right or east.

What else can I tell just by looking at the map?  I can see that the road (the red line) runs through a valley next to a couple of lakes.  I know that the terrain to the north and east is very hilly or mountainous, and that there’s a hill behind me.  So there’s plenty of information you can glean from a topographic map if you know how to read it.

Take the time and get yourself a topographic map of your area.  Sit down and give it a good look and you might be surprised at some of the terrain in your area.

A  good exercise is to plan a hiking route or a  bug-out route through terrain you haven’t seen before then actually go out and see what the terrain looks like.

One quick note about forested areas:  the map doesn’t tell you how dense the forest is.  In northern Maine the forest in some places is very thick and difficult to move through and in other places it’s a little more open.  The only way to really know for sure is to go out and have a look or talk to someone who’s been there.  A person who’s hiked the area you’re looking at can  be a wealth of information.

Questions?  Comments?

Sound off below!

-Jarhead Survivor

  • Mike the Gardener March 25, 2013, 9:17 am

    A tremendously helpful post … my friend and I are trying to learn everything we can about reading maps and this definitely helps.

    Reply
  • S.Q. Whrill March 25, 2013, 10:23 am

    I was in the civil air patrol (sp) and we were taught map reading
    I was about 10 or 12 at that time. great fun and learned alot
    about survival from that

    Reply
    • Jarhead Survivor March 25, 2013, 9:42 pm

      I’ve been working with my 11 year old nephew a little showing him how to read a compass and stuff. He loves it.

      Reply
  • j.r. guerra in s. tx. March 25, 2013, 1:48 pm

    Good to know – much obliged for the time to write this.

    I’ve wondered (and I apologize for drift here, feel free to ignore it), which hilly mountainous terrain is preferable to travel along, the crests (or military ‘crest’) or valleys. I recall reading a jungle travel book which mentioned the hiker had a lot of trouble, keeping himself oriented on which drainage he was traveling along because they hills wound upon themselves and the sun was often hidden from view because of canopy above.

    Reply
    • Jarhead Survivor March 25, 2013, 9:46 pm

      Hi j.r. – hmm, it’s a tough question and it depends on the terrain. If the ridge is thick with vegetation and lots of cliffs and stuff like that I’d probably prefer the valleys. But I almost always prefer the higher ground if possible because it’s easier to stop when there’s an opening and reorient yourself to your map. Always be on the look out for terrain features on land that can be seen on a map such as a river, lake, mountain, etc.

      Navigating in the mountains can be very tricky that’s for sure. Great question!

      Reply
      • j.r. guerra in s. tx. March 26, 2013, 1:32 pm

        Thank you J.S. for your reply. Where I live, we have hardly any elevation at all (stand on a telephone book and you get a view) so our contour maps have wiiiiiidddee gaps, lol. I’m just building up my knowledge base – which is why I often come here, lots of good information – discussion.

        Thanks again.

        Reply
  • George Henson March 25, 2013, 4:06 pm

    Thanks for your help. I was in boy scouts when I first started reading maps. Since becoming an adult I frequently use topo maps to find my way up 14 thousand foot peaks here in Colorado. This can be very helpful not only to keep from getting lost, but also avoid places that can cause serious body injury. Thanks for the report. I will be back for additional info in the future.
    George

    Reply
    • Jarhead Survivor March 25, 2013, 9:46 pm

      Thanks George. Sounds like you’re pretty squared away with your map reading skills.

      Reply
  • JL March 25, 2013, 4:37 pm

    This is very helpful, I am learning to read maps.
    There is a show called “Are You Tougher Then A Boy Scout ” you should check it out.
    I’m taking a little break from Facebook, but I will catch up on your posts when I re-enable it.

    Reply
    • Jarhead Survivor March 25, 2013, 9:47 pm

      Hi JL – I don’t watch tv, but it sounds like an interesting show.

      Keep at it as map reading is literally one of those skill sets that could literally save your life.

      Reply
  • des March 26, 2013, 2:40 pm

    Good article.
    From reading some of the comments its totally understandable why pacing and compass is such a useful weapon in your navigation arsenal.
    But understanding how to read the map recognising features especially in hilly/mountainous terrain is invaluable practice to navigating.
    I spent a short time at fort ord in california in the late eighties and we trained with a unit who escapes me now but we did a lot of stuff at hunter ligget training area i think…unfortunatley i dont have any old maps from there.
    Cheers

    Reply
  • Sgt. Survivor March 26, 2013, 10:15 pm

    Hey, I am loving this series. My question is, where do I come up with good topi maps? I have been looking for a while now and I haven’t found a decent topi map for my area (far east/central Oklahoma). Anyone who has a good source, it would be much appreciated. Some friends and I from the base go hiking over weekends and have been navigating using maps without legends that we have printed of of various websites. Thanks again!

    Reply
    • Joseph March 30, 2013, 3:24 pm

      The following link shows a high resolution topo for a random spot along Ferry Lake in eastern Oklahoma.

      http://www.mappingsupport.com/p/gmap4.php?utm=15N,322440,3954927&t=t4&z=15&coord=utm

      Full disclosure time: I am the developer of the Gmap4 software that is showing you the map. This project is part of my way to “pay it forward”. Translation: Gmap4 is free for non-commercial use. It is popular with people that enjoy a wide range of outdoor activities.

      Gmap4 is a browser app, not a native app. Gmap4 runs in most browsers on most devices from smartphones to desktops. Note that the browser does have to be online. When Gmap4 is running in the browser on a smartphone it automatically uses a phone-friendly ‘scroll’ interface. (If your phone does not like the scroll menu then touch Menu ==> Button Interface.)

      The button in the very upper right corner lets you change map types. In addition to topos for the USA, you can also look at vector topos for all of Canada. You can also surf the worldwide topographic OSM Cycle maps that include crowd-sourced trail data. The Menu button gives access to various features. A rightclick will show some useful info.

      The Menu ==> “Draw and Save” feature lets you add data to the map and then save your data as either a GPX file or a delimited text file. You can also save your data right in the Gmap4 link itself and not have to bother with any data file.

      Gmap4 can display these types of files: GPX, TPO, KML, KMZ, Google MyPlaces, and a delimited file format.

      I enjoy looking at topo maps and one of the main reasons I wrote Gmap4 was to make it easy for people to include map links when they post in forums like this one. Here is the recipe for making a link that will start Gmap4 and display a map:

      1. Simply use zoom/pan or Menu==>Search to find the area you want to see when the map opens.
      2. Click the button in the upper right corner and select “t4 Topo High” or one of the other choices. Also adjust the zoom to your liking (mouse wheel or sliding control in upper left corner).
      3. Click Menu ==> “Link to this map”. The link that is displayed will reproduce the same map you see on your screen.

      These Gmap4 links can be used in forum posts, emails, blogs, websites, etc.

      The Gmap4 homepage has a FAQ, examples, quick start info (in the Help file) and more to quickly get you up to speed.

      Gmap4 default map: http://www.mappingsupport.com/p/gmap4.php

      Gmap4 homepage: http://www.mappingsupport.com/p/gmap4.html

      Joseph, the Gmap4 guy
      Redmond, WA

      Reply
  • Sgt. Survivor March 26, 2013, 10:15 pm

    Hey, I am loving this series. My question is, where do I come up with good topi maps? I have been looking for a while now and I haven’t found a decent topo map for my area (far east/central Oklahoma). Anyone who has a good source, it would be much appreciated. Some friends and I from the base go hiking over weekends and have been navigating using maps without legends that we have printed of of various websites. Thanks again!

    Reply
  • Sgt. Survivor March 26, 2013, 10:15 pm

    Hey, I am loving this series. My question is, where do I come up with good topo maps? I have been looking for a while now and I haven’t found a decent topo map for my area (far east/central Oklahoma). Anyone who has a good source, it would be much appreciated. Some friends and I from the base go hiking over weekends and have been navigating using maps without legends that we have printed of of various websites. Thanks again!

    Reply
  • Sgt. Survivor March 26, 2013, 10:17 pm

    Sorry about the multiples, my browser hung up and lost its mind…

    Reply
  • TOM S March 26, 2013, 10:30 pm

    Great article. Never had a clue. After reading your clear and simple explanation, I was able to see everything you did. Makes me want to look into this a lot more.

    Reply
    • Jarhead Survivor March 27, 2013, 2:59 pm

      Thanks Tom. You should check it out. It might seem intimidating at first, but after you do it for awhile it’ll seem like second nature.

      Reply
  • irishdutchuncle March 27, 2013, 12:13 pm

    back when I was taking flying lessons, I realized how really unfamiliar I was with my home territory. (I often couldn’t say what the places were, that I was flying over) since then I’ve aquired street maps for the whole region. (always a huge help to me before my wife got a phone with GPS) I really, really like knowing where I am. (especially after dusk) I love the ammount of detail there is with a toppo map. sometimes the street maps will say the name of a mountain. the toppo map shows me where one mountain ends, and the next begins. (way cool)

    Reply
    • Jarhead Survivor March 27, 2013, 2:58 pm

      It looks very different from the air doesn’t it? When I was riding around helicopters in the service I can remember being confused because looking at the ground from the air didn’t match my mental image of what it would look like.

      Studying a map will help with that.

      Reply
      • irishdutchuncle March 28, 2013, 8:58 am

        now there’s Google Earth. that’s almost like being there.

        Reply
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    Reply