The lost highway
Dogs use their keen sense of smell, birds track Earth's magnetic fields, and we take a highly detailed map and stare at it with blind panic. If you need to bone up on your cartographic competence, be it for a trip across town or across the country, we'll help you get where you want to go.
For this 2torial, you'll need a local map and a U.S. road atlas, which will include a national map as well as more detailed maps for each state (and most major cities), arranged alphabetically. Both should be available
Use the grid
Before you go anywhere, you need to locate your destination and the point where you'll begin. To do this, use the map grid. The grid is indicated by a series of numbers (starting with "1") listed across the borders of two opposing sides of the map, and a series of letters (starting with "A") listed across the other two sides. Vertical and horizontal lines usually run between like numbers and letters across the map.
To use the grid, first consult the grid index, which is a list of streets (for local maps) or towns and cities (for state and national maps) with their corresponding grid position. For local maps, the index should be easy to find (check the map's back side if you don't see it). In a road atlas, a state index is usually printed in a box on the state's page, but if it's not, you should find a national index organized by state in the front or back of the atlas.
Once you've found the street, town, or city, note the grid location next to the name (for example, "Harrison Ave.--E-5" or, "Peterborough--S-12"). Find the corresponding letter and number on the map borders and trace the grid lines inward until they meet on the map. Within the square where they connect is the street, town, or city you're seeking.
Once you've found your location and destination, mark them on the map clearly so they'll be easy to spot later on. Now it's time to figure out how to get from here to there.
Consult the key
Speedy course or scenic route? Interstate, state highway, or back road? And oh, those one-way streets! To plan your trip, you have to know both the road systems and type of travel you're looking for. The best way to do both is to consult the map's key (also called a legend). Usually located in a small box at one corner of the map, it typically contains the following important data:
- The map's scale--usually 1 inch (2.5 centimeters) equaling a certain number of miles or kilometers
- Classifications for local roads, state and federal highways, interstates, toll roads, and so on (these will also include highway markers--symbols for the different highway systems that also contain the highway's particular number)
- Population symbols that mark a town or city's size and its position on the map
- Symbols for man-made and natural landmarks
Different map publishers will use different classifications in their map keys, but each should have a logical, easy-to-follow system.
Navigate the local roads
To the uninitiated, a local road map can look like an unending maze. Don't panic. While different maps will have different road classifications, they all generally work on one basic system: the bolder the road appears on the map, the more prominent it is. After you've found your location and destination on the grid and consulted the key, decide on your route by picking from these main road types:
Primary roads are usually marked with the boldest line (unless a highway passes through the town or city). These are main thoroughfares for the area. They're built for speed and usually have double lanes for each direction of traffic.
Secondary roads are marked with a less bold line. These are also for rapid transit, but are typically two-laned and can move through residential areas as well as business districts.
Minor roads are usually marked with a gray line. These are slower routes, but they can sometimes provide a good shortcut or a more scenic drive.
Unpaved roads and trails are great for scenic trips. They're usually marked by a broken line. Just make sure they aren't private (these should have a special classification), and if you're driving, make sure cars are allowed, and that there aren't any seasonal restrictions, like flooding or snow.
Hit the highways
Once you travel out of town, you'll probably be using some part of the nation's highway system (although with many state and national highways passing directly through urban areas, you might use them for speedy in-town trips as well). Here's how to locate the three main types:
State highways typically have a highway marker that's a number within a white circle or oval. These roads are usually two lanes (sometimes switching to four lanes in more urban areas), so they're not always the fastest routes for long distances.
Federal highways have a shield-shaped marker surrounding the highway number. Like state highways, they're usually two to four lanes. But what they may lack in long-distance speed, they can usually make up in the history behind them (and along them), as they were the first national highways built in the U.S.
Finally, there's the interstate highway system, four- to eight-laned behemoths that criss-cross and link up the country. These are probably your fastest choice for longer distances, because unlike most federal and state systems, interstates are limited access highways, which means you can only get on or off at specific intersection points, usually marked as white squares on the map's road line. The highway marker for the interstate system is a shield-shaped symbol (although unlike the federal highway marker, interstate markers are usually colored). The interstate will be the boldest road marked on any state or national map.
Understand the symbols and colors
Since road maps are pressed for space, they often employ symbols as shorthand for landmarks and structures. Usually these symbols are defined within the map's key. But map keys can be pressed for space, too, and the terse definitions given can be a little hard to understand for the beginner. Here are some guidelines to help you along:
Colors. While the basics are easy to understand--blue marks bodies of water, green marks natural areas, like local, state, and national parks and refuges--the other colors can be trickier. Different shades can mark urban areas, counties, states, federal land, reservations, and so on. Consult the key (if you're using an atlas, consult the master key, usually located in the first few pages).
Symbols. Most of these are also fairly straightforward. An airplane will denote an airport, a tent means a campground, and so on. For atlases, consult the master key if you don't see the symbol on the map key. Just be careful you don't get them mixed up on the map (for example, a camping symbol and a mountain symbol can look very similar on many maps, as can an airport and an air force base).
But once you get into the swing of map reading, you'll find navigating a snap. From the littlest country road to the largest eight-laned highway, it's always nice to know exactly where you are.
