Topographic Maps

Contents

Introduction

Map Scale

Map Symbols

Available Products and Coverage

To Obtain Maps

Information

Introduction

Whether on paper or on a computer screen, a map is the best tool available to catalog and view the arrangement of features on the Earth's surface. Maps of various kinds--road maps, political maps, land use maps, maps of the world--serve many different purposes.

One of the most widely used of all maps is the topographic map. The characteristic that distinguishes topographic maps from other maps is the use of contour lines to portray the shape and elevation of the land. Topographic maps render the three-dimensional ups and downs of the terrain on a two-dimensional surface.

Topographic maps usually portray both natural and constructed features. They show and name natural features, including mountains, valleys, plains, lakes, rivers, and vegetation. They also identify the constructed features, such as roads, boundaries, transmission lines, and major buildings.

The wide range of information provided by topographic maps makes them extremely useful to professional and recreational map users alike. Topographic maps are used for engineering, energy exploration, natural resource conservation, environmental management, public works design, commercial and residential planning, and outdoor activities like hiking, camping, and fishing. The U.S. Geological Survey (USGS) produces topographic maps at several different scales to meet these various needs.

Map Scale

The most important consideration in choosing a map, with its defined map scale, is its intended use. Different scale maps provide different levels of detail in terms of features presented.

Simply defined, map scale is the relationship between distance on the map and distance on the ground. That is, there is a direct relationship between a unit of measurement on the map and the actual distance expressed in the same unit of measurement on the ground. If, for instance, 1 inch on the map represents 1 mile (which converts to 63,360 inches) on the ground, the map's scale is 1:63,360.

The USGS has produced topographic maps for the entire country at different scales. The most commonly used topographic map produced by the USGS is the 1:24,000-scale quadrangle map. These maps cover 7.5 minutes of latitude by 7.5 minutes of longitude. There are more than 54,000 1:24,000-scale maps that cover the contiguous United States and Hawaii. Alaska is covered by maps at 1:63,360 scale. Maps at this scale provide detailed information, including the locations of major roads, rivers and lakes, vegetated areas, boundaries, and important buildings, as well as campgrounds, caves, ski lifts, watermills, and even drive-in theaters. Footbridges, drawbridges, fence lines, private roads, and changes in the number of lanes in a road are also shown at this scale.

In addition to the 1:24,000-scale maps, complete topographic map coverage of the United States is available at scales of 1:100,000 and 1:250,000. Information content on these smaller scale maps is essentially the same, though features are generalized or omitted as the scale of the map decreases and the area covered increases.

Map Symbols

All features are represented on USGS topographic maps by a set of standard symbols. For example, the topography (the shape of the land) is shown by contour lines. Usually brown, these lines show the ground surface at a constant elevation. Woodlands are shown in a green tint; waterways, in blue. Buildings may be shown on the map as black squares or outlines. Recent changes in an area may be shown by a purple overprint. A road may be printed in red or black solid or dashed lines, depending on its size and surface.

Available Products and Coverage

To Obtain Topographic Maps

To purchase USGS topographic maps or other USGS printed products, contact your nearest USGS published products Business Partner.

Information

Detailed information about topographic maps is available at http://topomaps.usgs.gov/.