How a Modern-Day Mapmaker Does His Job

Tom Harrison, a Californian cartographer, explains what goes into a good map and why making one can take nearly two years.

Tom Harrison (Rebecca Clarke )

Mapmaking is a huge production these days: Google reportedly has over 1,000 full-time employees and 6,000 contractors working on its digital maps.

So it’s easy to forget that detailed maps can be made by just one person, and that paper maps aren't a thing of the past: They are extremely helpful to anyone navigating without a cellular signal, and specialized maps can contain information, such as hiking trail junctions or topography, that can make trekking safer. Tom Harrison is a cartographer based in San Rafael, California who has been making and selling his own maps since the 1970s. His maps are made for hiking, backpacking, and mountain biking in the parks and wilderness of California.

For The Atlantic’s series of interviews with American workers, I spoke with Harrison about how he collects information and makes his maps, and why he doesn’t hire anyone to help him. A lightly edited transcript of our conversation follows.


Bourree Lam: How did you get into mapmaking?

Tom Harrison: I’ve been doing it for 30 years. I have a bachelor’s degree in geography, and my first job was being a California state-park ranger. And people were asking, “Where can you get a really good map of the park?” Well, the parks aren’t interested in making really good maps. The parks make what we call information graphics. So I thought, you know, there’s a business in this.

I was a park ranger for about seven years, and I loved being a park ranger, but I didn’t like working with the park service. So I left, got my master’s degree in geography and started making maps. They say write what you know about if you want to be a writer. Well, I mapped what I knew about. So I started mapping parks, and one thing led to another.

Lam: What is your process for making a map?

Harrison: The first thing is just to look and see how many people are going to an area, so you find the popular places. I find out which places people are interested in going, and I drive around to all the campgrounds and trailheads and look at the license plates to see where they’re coming from and if there’s a market to sell the maps.

Making a map is like any other kind of project you can think of—painting a house, making a quilt, preparing a big fancy dinner for friends. There’s a lot of work and research that goes into it. You have to look and say: How much has already been done, and do I have to do it all over myself? Is there information out there that I can get for free, or pay for?

A lot of research is looking into where the data is coming from, because maps are very information-rich graphics. There’s roads, and trails, and lakes, and elevations, campgrounds, all those squiggly lines we call contour lines on elevation. And the question is: How do you find that information and how do you make it all fit together? So there’s a huge amount of research into the best and easiest way to get that data, and how to make it all come together. And that's a tremendous amount of work.

Lam: How long does it take to make the map once you decided on a location?

Harrison: Usually about two years. Things have gotten a little easier over the years. I used to go out and hike every trail. I’ve done a lot of trail hiking with a measuring wheel and a GPS unit. There are some places in this country where the maps are quite old, and some of them don’t have the trails on them that the parks have. They don’t have the boundaries. And finding that information is really time consuming.

Over the years, I’ve figured out various ways of finding that data and double-checking that data. I don't have to go quite as often as I used to. You’ve got the field work, you’ve got the research, then you’ve got the compilation—bringing it all together.

Lam:  Has your mapmaking process changed since you started in the 1970s?

Harrison: Oh yeah. It changes about every 6 months. I figure out what I hope is a newer, easier, faster way of doing things.

One major thing I’ve changed in the last couple of years is using information that’s available from the different park and forest agencies. Those agencies use something called GIS, which means Geographic Information System. And it’s basically like a database of all the features in an area, and this information is attached to actual lines you see on a computer screen.

But reading that GIS data takes some pretty sophisticated software. So I started using that. Of course, most college students know how to do that these days, but I’m not a college student anymore. So I’ve learned how to find that data, and make it work in my drawing program. I use Adobe Illustrator, which is basically just a drawing program. But it has a plugin that reads GIS data. So I can bring it in and put it exactly where it fits on the map. That’s been a big change over the last couple of years.

Lam: I read this on your website, regarding employment: “The company consists of Tom and Barbara Harrison who do all the research, map production, business administration and general operations. We have worked as a team since 1976 and are very proud of the fact that just the two of us have been able to compete successfully in the outdoor-retail market. We don’t have any employees, and we have no plans to add employees. Sorry.”

Can you tell me about how you and your wife became a team? And why it’s going to continue being just the two of you?

Harrison: Well, I don’t really like to have employees. When we first started doing this 30 years ago, we were both right out of grad school. I started doing this, but wasn’t making any money for a while. Thank goodness she had a job to pay the rent and the bills. For about 7 years, I worked really hard trying to get the business going, and it was going pretty good.

Her job was starting to be kind of a pain, so I said, “Why don’t you just quit your job and come work with me?” So she started doing some of the things that I didn’t have time to do—some of the accounting, some of the cleaning up of the earlier files, prepping things. And then we just worked together like that for a good number of years.

And as far as employees, we work at home. I don’t really want to have an office—that’s kind of silly. I just work on a Macbook Pro laptop. I never wanted to have a big company or a big business. I just wanted to make maps and, with any kind of luck, support ourselves. So I just don’t see any need to have any other employee—we’re quite happy just the way we are.

Lam: What’s involved in creating not just a map, but a good map?

Harrison: One of the secrets of making a good, easy-to-read, map is what you leave off the map. A lot of maps have way too much stuff. When you’re reading a map, your eyes are going back and forth. And if you have too much stuff, your eyes go back and forth too much and your brain cannot process everything it's seeing.

Being a former park ranger, I know that people can get in trouble in the outdoors without any help from me or anybody else. People want to know, where does the trail start, where can I go camping, how far is it from this point to that point, is it up or down? Those are the basic things they want to know. So I try to put the important information in the visual foreground, and the stuff that carries the body of the map—the contour lines and the vegetation and streams and things—that’s in the background.

My customers are hiking, or riding their bicycles, or on horseback, and that’s the main thing they want to know. In California, a lot of search-and-rescue teams use my maps, because they can get to where they’re going fast—they can read them easily. So it’s just one of those things: It takes time and a lot of OCD to get the type exactly where you want it. And I do a lot of things so it flows and looks visually pleasing. At least to me, anyway.

Lam: What’s your favorite map that you’ve ever made?

Harrison: I like them all up until the last week or two, and then I hate it. I just want it on the press—I’m tired of looking at it. I don’t have a favorite one that I’ve made but some were easier than others.

It’s funny though, I look back on some of the stuff I made 25 to 30 years ago, and I used to think “Oh my god, it’s horrible, why did anybody ever buy that thing?” Today I think, “Oh, it’s much nicer.” But even today, we’ll go on press and a map will look good, and I’ll get home and say “Ehh, you know, I could have made that color a little bit stronger or a little bit weaker.” There's always something that you can tweak. You never ever find the mistakes until you’re on press, and you’ve got 6,000 sheets running off that press.

Actually, I like making all of them. They’re all interesting, they’re all a challenge, and if I didn’t like the area or the way the map looked, I wouldn’t make it. I only want to do things that are interesting to the public, of course, because I have to sell them. But also interesting to me, because I want to have some kind of feeling that this is worth doing. I spend a huge amount of time, money, and effort doing them.


This interview is a part of a series about the lives and experiences of members of the American workforce, which includes conversations with a tour guide, a park ranger, and a hotel manager.

This article is part of our Inside Jobs project, which is supported by a grant from the Rockefeller Foundation.

Bourree Lam is a former staff writer at The Atlantic. She was previously the editor of Freakonomics.com.