One of the skills that will help you this archery season is learning how to read a topo map. It doesn’t matter if you are using Google Earth, a hunting app, or a standard printed map; understanding how to look at the contour lines on a topo map and associate them with the terrain you are walking on. In addition, it will allow you to be better at land navigation and hunt a lot more effectively.
I have spent many days and nights pouring over topographic maps, planning navigation routes, estimating distances, and looking for obstacles and hazards that could affect me along the way. I learned a lot about reading topo maps and navigation during my 21 years in the U.S. Army. As a former Green Beret, I had to be able to plan, navigate, and execute missions anywhere in the world, and sometimes the only thing I had to use was a military 1:50,000 topo map.
The knowledge I gained in the Army has been an essential part of my success in archery hunting. I can look at a map and quickly identify what the terrain is like, where possible hunting spots are, and how I am going to get there. What you find on the ground when you get there might be different than you expected, but a little preparation goes a long way. It doesn’t take a lot of effort and you’ll learn how to too once you read this blog post. Continue reading or watch the video below to see how you can learn how to read a topographic map in the next 20 minutes.
- Always Orient Your Map to North First
- Contour Lines and How to Read Them
- The Legend, Scale, and Declination Diagram
- North and the Declination Diagram
- The 5 Major Terrain Features
- The 3 Minor Terrain Features
- The 2 Supplementary Terrain Features
- How to Use Map Colors for Hunting
- Map Symbols for Hunting
Always Orient Your Map to North First
The first thing you should do anytime you look at a map is to make sure it is oriented (facing) to the north. This is a critical first step if you want to be able to look at the map, then look at the terrain in front of you and associate it correctly and navigate without getting lost. This is the same whether you are using printed maps, maps online, or a mobile hunting app. Always make sure your map or app is facing north when you are looking at it so you can associate what you are seeing on the map with what you are seeing in front of you correctly.
To assist you with this, you should always carry a compass that allows you to set the proper declination for north. This will help ensure you are always heading in the right direction. More on this is below.
Contour Lines and How to Read Them
What are Contour Lines?
Contour lines depict the slope (up or down) of terrain. They show you the way terrain flows and its changes in elevation. They help define major and minor terrain features, their size, inclines, potential obstacles, etc. Each contour line depicts a specific elevation above sea level. These elevation variations change between each contour line. This elevation change between lines can range from as little as 10 feet to as much as 100 feet depending on the map you are using and will determine the degree of slope between them.
There are three types of contour lines:
- Index – These are the bold lines that normally have a round number in the hundreds depicting the elevation. Ex. 1000, 1100, 1200, 1300. Sometimes these lines won’t have a number on them and you will have to look at the closest numbered Index line and count to see what the elevation is for that particular line.
- Intermediate – These are the solid lines between the Index lines. There are normally four (4) supplementary lines unless the elevation changes sharply up or down.
- Supplementary – These lines are depicted on the map as dotted lines and they are used to show flat or more level terrain.
Reading Elevation Changes on a Topo Map
When looking at contour lines on a map, mobile app, or tools like Google Earth, it is important to understand the flow of contour lines and what they mean to elevation (how steep or flat the terrain is). The closer together contour lines are, the steeper the terrain will be. The farther apart they are, the more the terrain will slope. When these lines are really far apart, the terrain will be flatter or more level in appearance.
This can be deceiving when using mobile apps as you zoom into different areas. Make sure you always look at the contour lines to see what the distance in elevation is between each line. Most maps will have a legend that will show you the distance in feet between each line (this is called contour interval) and will show you the scale (miles, meters, yards, feet, etc.) of how distance is shown. If the contour interval is 20 feet, then you will know that when you see an index contour line (as shown in the picture below), the lines that are not marked are exactly 20 feet apart in elevation each.
This will give you an idea of how steep or flat an area truly is when using a map, online tool, or mobile application to scout or navigate through an area and will tell you what major and minor terrain features are there.
The Legend, Scale, and Declination Diagram
The legend on a map is normally at the bottom and will tell you how to associate the size of what is on the map with what you actually see. The legend also tells you the Datum, what the grid system is and what distance it represents, and the map’s declination. This begins with the map scale.
The map’s scale is very important to understand as it allows you to relate size and distance. For example, you might see that a map is a 1:100,000 scale (ratio). This means that 1 centimeter (cm) on the map equals 1 kilometer (km) on the ground. You will notice that other “scales” are listed on the map that will show you the distance on the map in meters, kilometers, and/or miles. What you normally will not see is nationally published maps, like those from the U.S. Geological Survey (USGS), showing distances in yards. Most distances, outside of miles, are shown using the metric system. This is important to know when navigating or estimating distance.
Most USGS maps (that you can get for free using the link in the paragraph above) use a 1:24,000 scale. This is why I recommend buying a cheap protractor that matches those maps and others used in the U.S. Protractors allow you to plot distances, and azimuths (direction in degrees and mils), and estimate distances between locations you are navigating to very quickly. I recommend a UTM and MGRS (military) capable protractor, like this one when using these types of maps for hunting.
North and the Declination Diagram
One of the most difficult concepts for new map readers is understanding the concept of the declination diagram on a map. To make it simple, the reason for this diagram is that there are three types of north. True north, which points to the North Pole; grid north, which is the north the map lines point to; and magnetic north. Magnetic north is the north you find on your compass. Magnetic north is different everywhere in the world and is not always pointing directly at the North Pole. In fact, sometimes it is way off.
This is why the legend contains what is called a declination diagram. This diagram shows you the difference between the north on the map and what your compass is showing you. This is different everywhere you go, so make sure you check the declination for the area you are hunting in before you go. This can get you seriously lost if you don’t know it and it probably has already.
You can see from the image above that there is a difference of over 10 degrees (or 195 mils). This difference when using a compass can really throw you off course. This is why it is important to use a compass that allows you to adjust it for declination. Once you do this, you can simply navigate and not worry about what north is. The other designation you see on the diagram is the difference between true north and grid north. That is only just over 1 degree (or 28 mils) on the example diagram above.
*NOTE: If you are using a mobile hunting app, make sure it includes all compass azimuths with the declination included.
The 5 Major Terrain Features
There are five major and 3 minor terrain features, but there are also several supplementary terrain feature variants of each that can be used to define a specific area or to see where there are potential locations where deer or other animals you are hunting may travel, bed, or feed. Each one of these features has a unique way of being displayed using contour lines. The way each one is shaped, its direction of slope, and its high in elevation it is can really make or break your route when hunting.
Here are the five major terrain features you will find on a topo map:
A hill or a hilltop is depicted as the highest point in elevation where the ground slopes down in all directions around it. It is a point of high ground that can be referenced for navigation purposes. Its line is connected, often in a circle shape, but sometimes cylindrical. It is always connected to itself and at the highest point of elevation for that particular spot.
A ridge is a line of high ground that goes on for a distance. It can be considered a series of hills, but a ridge is more of a continuous line of high ground with two opposing downward slopes in opposite directions. When someone says they are running or traveling along a ridgeline, they normally mean they are navigating along a contour line on the ridge at the same elevation and do not mean the top. See how the lines run below.
A bench is an area on a ridge or ridgeline that has a semi-level area on the side of the ridge. Some ridges can have multiple benches. These areas can be hard to identify on a map if it is small. This is shown on a topo map as a location where the contour lines spread apart farther than the normal flow of the ridge and can be just below a sharp incline and/or decline in elevation along the ridge.
Benches often are areas where deer will bed or use as lateral travel routes along the ridgeline. Mature bucks tend to bed on the military crest of a bench on its downward slope.
A valley is an area of low ground, sometimes with a stream or river in it, that has high ground around it on two or more sides. Large valleys are sometimes the low ground between two or more ridges or hills. The elevation is normally at its lowest point at the bottom of the valley.
A saddle is defined as the low ground between two or more opposing hilltops or it can also be a break of low ground on a ridge. Saddles are commonly used by deer as travel routes, more often during the rut, but they seem to provide cover in a lot of cases and that is why deer use them for travel.
A depression is a low point or hole in the ground surrounded on all sides by high ground. A dry lake bed is a great example of a depression. I couldn’t find a good example in my map recon, so I had to use the example from the Army Study Guide below. You will notice that a defined depression on a topographic map will have small lines facing inward around the entire depressed area (as shown below).
The 3 Minor Terrain Features
The three minor terrain features are all branches of the major terrain features. Some people call them different things, but these are their formal names.
Draw (or Ditch)
A draw is like a valley, but a lot smaller in size. A draw, sometimes called a ditch if it has a sharp grade or is small, is low ground that slopes away from high ground that surrounds it on at least two sides. Depending on the size of the landscape you are working with, draws can be very small or they can be extremely large. Small, sharp draws are sometimes called ditches. This is especially true if they have water in them like a small stream or creek. In hill or mountain areas, a draw will often have intermittent streams or springs running down it.
Spur (or Point)
A spur, sometimes called a point by deer hunters, is a sloping line of ground that branches off of a ridge or hill and can be small or large. A lot of times a spur is surrounded by two or more draws. Mature bucks tend to bed on the leeward (downwind) side of spurs (points). When you hear deer hunters talking about deer bedding on points, they are talking about a spur and vice versa. That being said, some locations that are referred to as points are the end of ridgelines and wouldn’t necessarily be classified as a spur.
A cliff is defined on a map by a series of contour lines that are extremely close together. The size of a cliff will be determined by the size of the contour line interval. A sheer drop-off type cliff will be annotated on the map just like a depression in the terrain, except the small tick marks, will be facing downhill instead of inward. Not many people have trouble identifying what a cliff is, but even if you don’t classify an area as a cliff when the contour lines are close together, you need to be wary of how steep the terrain is before trying to navigate up or down it.
The 2 Supplementary Terrain Features
The two (2) supplementary terrain features are man-made but are shown on a map because they can take up large areas and need to be identified as potential obstacles.
A cut is a man-made cut into the side of a ridge or piece of high ground. A lot of times this is depicted for railroad lines or large-scale construction projects or quarries. A cut is shown on the map with opposing contour lines with tick marks facing inward like that of a depression.
A fill is a man-made line of stone or soil fill that’s been added to provide support or level the ground in an area. Fill can commonly be seen on both sides of a highway, road, or rail line. Much like a “cut”, a “fill” is shown on a map with two opposing contour lines, but the tick marks will be facing outward in the direction of the fill versus inward like a cut. See the image below for a visual representation.
How to Use Map Colors for Hunting
While most map colors are self-explanatory like blue is used to identify water. Being able to identify vegetation and obstacles is extremely important. The color green is used to depict vegetation. The darker the green, the more dense the vegetation is. If there is a combination of light green and white, it identifies a sparsely vegetated area. The color white is used to depict an open area that is not vegetated or is an open area or area that is used for agriculture.
Map Symbols for Hunting
It is critical to know all of the different symbols you will find on maps when using them. There are way too many to list here. It is critical because as hunters, we need to know where the roads turn into trails, where there are gates, bridges, boat ramps, and more. All of these things are important and need to be identified properly. This is why I recommend downloading the USGS Topographic Map Symbols PDF. It shows you everything and is a great guide for beginners and advanced users alike.
Now you should have a good understanding of how to read a topo map for hunting. This will help you regardless if you are using old-style physical maps from the USGS or one of the new mobile hunting apps on the market. I highly recommend buying or downloading a few maps, getting a solid compass and protractor, and seeing what you can do to use maps for hunting like never before.
If you have any questions, please let me know in the comments below. Good luck!
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