Travel Advice - Map use – Browse the legend to understand the symbols used on the map

Your ability to use maps during travel depends on understanding of the marks and symbols used to create these miniature displays of the real world.  Symbols on maps represent a unique graphic language.

There is no explicit agreement between cartographers on the marks and signs that are used to represent real world features on maps. In fact, similar looking symbols may be given a different meaning on each map you examine.

Cartographers attempt to employ visual logic when creating maps by associating real world features with the type of symbol used to represent them on maps.

• Lines, for example, are used to symbolize linear features such as rivers, roads, and borders.
• Areal features, such as parks, are shown by filled area symbols (e.g. a polygon filled with color) that represent the location and boundaries of the object at map scale.
• Point phenomena, for example, park entrances, points of interest, or other discrete features, are shown with a point symbol, such as a dot or a small square.
• Some features displayed on maps, however, are not shown by easily interpretable symbols (e.g., height above sea level is often shown by lines of constant elevation, called contours)

 In order to understand the meaning of the various symbols used on a specific map, you need to refer to the map legend.

• The legend is a small table that should include a graphic depiction of every symbol shown on the map and a brief description of the feature that it represents.
•  Look for the legend in or near the margin of the sheet or page.
• It will usually be surrounded by an outline and prominently displayed. If you use an atlas product, it is likely that a full legend will be found in the book’s front material.

When you examine the map’s legend, you will notice that geographic features considered by the cartographer to be important during map use are represented by symbols that are visually more important (larger or more conspicuous) than items of lesser significance.

• For example, different types of roads (highways and streets) are represented with line widths and colors are used to make one symbol appear visually more important than the other.
• Similarly, the symbols used to display road numbers (called road shields or markers) are drawn so that the numbers of the most important routes (e.g. national routes and Interstates) are more visually dominant than the numbers of less important routes.

If the map does not have a legend, you should be safe in assuming the following:

1. Large names represent more important or prominent items on the map (e.g., the biggest cities are shown with the largest symbol and the biggest type used for cities on the map).

2. Major highways or toll roads are shown by larger, more contrasted lines. Shields indicating road numbers for major highways are larger or more colorful than those used for roads of lesser significance.

3. Lines on maps usually represent roads, rivers, canals, or boundaries. A little visual inspection can help you tell which symbol represents which feature. Rivers are symbolized in blue and have a more complicated geometry than most roads.

4. Points of interest (locations that a traveler might want to visit) are shown by point symbols (a dot or a square) if they represent building such as visitor centers, museums, etc. If the feature is a park, it will be shown with a colored area symbol showing the extent of the feature.

5. Many points of interest are shown by symbols that look something like the real feature. Forests may be represented by a small, pine tree-like symbol. A forest that provides campsites might be shown with a small, pine tree-like symbol accompanied by a tent symbol. A roadside rest may be represented by a stylized picnic bench.

6. Most mapmakers create abbreviations for points of interest that you can figure out, as they follow a pattern. For example, many map publishers use SP for State Park, NP to indicate National Park, and NF to represent National Forest.

Finally, read the rest of our articles on how to use maps.  Click here for a list of our map-use articles.

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