Have You Ever... Learned How to Read a Topo Map?

This is part two of our interview with Amelia Hagen-Dillon of Cairn Cartographers. If you missed part one, it's worth checking out. So I thought it would behoove us non-cartographers to learn some basic skills to help us understand maps. And while we're at it, play a little trivia! Keep track of your answers and submit them in a comment below.

Let's get started! For those who might not know what "Topo" means, let's start with some basics before jumping into the interview with Amelia. 

What is a topo map?
Wikipedia defines a topographic map as "a detailed and accurate graphic representation of cultural and natural features in the ground." Um, so in lay(wo)man's terms, it's basically a map that gives enough information to help us get a sense of the terrain of the mapped area. A topo map is the next best option to having a 3D pop-up replica in our pocket, The type of graphics used (like contour lines and shaded/darker regions) tell us if an area is steep, has rolling hills, deep canyons, etc.

TRIVIA QUESTION 1: Which one is the topo map? The image on the left or the right?

How do you pronounce "topo?"
I've heard people say it like "toe-po" or "tah-po."

TRIVIA QUESTION 2: What do you think is the correct pronunciation for "topo?" 

Okay Amelia, pretend I'm an alien on Earth and I've never seen a topo map. Will you walk me through all of the major characteristics I should understand about how it works?
At the most basic level, a map is an abstract representation of a landscape. I think of maps in two ways: 1) as a way of depicting a landscape on a scale we can wrap our brains around and 2) a way of putting one’s immediate surroundings into the context of a bigger picture.

The most basic components of a map are the scale and the orientation. The orientation just means which way is which. For most maps, including ours, this means north is at the top of the page. This is usually shown with a compass rose. One important thing to notice is the declination. Without being too long winded, declination is the difference between true north and magnetic north, it depends on location and changes over time so most maps will have the current declination for the given area in the compass rose. You can read more about declination here.

compassrose_scale.jpg

The scale is a way of determining how the map compares to the actual landscape. You’ll often see this as a number. 1:24,000 for example is the scale of the old USGS quads which means one inch (or mile, or foot or yard or meter or kilometer) on the map is equal to 24,000 of the same unit in the actual landscape. Scale is also usually given with a scale bar which shows how much a familiar distance would cover on the map. For example, a map with a scale of 1:63,360 one inch on the map is equal to one mile on the landscape.

What do you think is the most important information I need to understand, in order to
read a map?

The most important information on a map really depends of what the map is for. There needs to be something that the viewer can recognize as familiar so they can put things in context. On a map of an urban area this might be major road networks or familiar landmarks. For a map of the wilderness, it’s topography, vegetation and water (in the form of streams, rivers and lakes).

In the image below, there are many creeks all over the map. Do you think any of those are rivers? Well, rivers tend to be indicated with a thicker line than the ones used to indicate creeks below. Also, none of these are labeled as a river; they are all labeled as creeks. 

When I’m making a map, I think about what is going to be obvious to a person looking around them at the landscape, and then I try to convey that information on the map. Topography is probably the biggest thing that can be shown with contours, shaded relief or both. We use both on our maps. As a result, we get a lot of people telling us our maps actually look like the landscape, so it’s easier for them to read than a map with contours alone.

readingamap.jpg

Another big one is vegetation. The green and white/gray in the background on our maps shows forested and non forested areas. It’s based on the data from the old USGS quads but we update it because it can be helpful to see big meadows or avalanche chutes and figure out where you are using them. We use the most detailed hydrography data we can get and we update the biggest rivers using the most recent aerial images to make it as accurate as possible.

If I'm lost on the trail, how would I use my map to figure out where I am?
The first thing I do is look for a landmark around me. This might be a bend in the river that I can see or a spot where the trail is right next to the creek, or maybe a long flat section on a ridge. Anything I can notice about where I am and then I imagine how that would look on my map. Then I orient the map and try and locate the landmark on the map. Here’s the thing: our brains don’t like to admit they are wrong. If you think you’ve been heading down one ridge your brain will try to convince you the map matches the landscape even if it doesn’t. This is why GPS can be great tools. Even the most basic GPS will give you your coordinates and you can locate yourself on the map with those.

In the image below, you can see correlating landmarks on the map and the photo. By identifying a landmark like Haystack Butte, you can then identify Elk Creek drainage and road.

TRIVIA QUESTION 3: Where was this photo taken from? A, B, or C? (Extra credit: How do you know?)

What should I look out for that indicates a trail is difficult?
This depends on what you think makes a trail difficult! If long steep climbs intimidate you than trails that cross a lot of contours or are in the darker shaded parts of a map are probably going to be steeper. Personally, I think the hardest trails are the ones that aren’t frequently maintained and are hard to follow. It can take so much mental energy to be constantly searching for the trail or climbing over downed logs. On our maps, we symbolize trails by class, so more frequently maintained trails are a different color than trails that might be hard to follow so people can have an idea of what to expect as far as trail conditions go.

What are maps useful for?
I think maps are most useful for planning a trip when you need to be able to see a large area all on one page and a GPS or computer screen isn’t big enough. I also love having a map when I reach a high point or somewhere with a big view and I want to be able to identify landmarks in the landscape around me.

Do we still need maps if we have GPS? 
When I tell people I make maps, often their first response is, “Aren’t maps being replaced by GPS?” You can read a whole blog post about how I think maps and GPS are both important tools, here.

Why is a map important to have in the wilderness?
The fact that a map can’t run out of batteries or break is always a big plus! If you need to figure out where you are or how to get to where you want to go, a map and the skills to read it will help. For me, I really love to know where I am in context of a larger landscape. A map is the best tool to help me understand that.

 

I hope this interview provided you a basic understanding of maps. Here are two final trivia questions:

TRIVIA QUESTION 4: Where did Amelia meet her partner Jaime?

TRIVIA QUESTION 5: How many times does Amelia mention the word "context?" In what context?  ;-)


Submit your FIVE trivia answers in the comments below FOR A CHANCE TO WIN A CAIRN CARTO MAP OF YOUR CHOICE!

  • Include your full name, email address & your answers in your comment below.
  • Submit your answers by March 5, 2015

UPDATED on 3/5/15:

ANSWERS:
1. The map on the RIGHT
2. The pronunciation of "topo" depends on where you're from. No wrong answer!
3. C
4. In Yellowstone, during a summer internship
5. Three. The word "context" is mentioned in reference to a larger landscape.

WINNER:
Samuel Mandell! You get to choose a map from Cairn Cartographics' collection! (I'm glad we live together because we can share. Yay!)


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