The first features usually noticed on a topographic map might be the contour lines, shown in brown. Other major features such as vegetation (green), water (blue), and densely built-up areas (gray or red) are easily recognized. A grid also overlies the entire map. The grid generally represents a one-mile-square unit. This unit is an administrative land parcel system referred to as a section. Geodesic lines will also be evident, a universal land system established throughout the United States by the U.S. Geological Survey. Both natural and man-made features are shown by lines that may be straight, curved, solid, dashed, dotted, or in any combination. The colors used generally indicate similar types of information: topographic contours (brown); lakes, streams, irrigation ditches, and other water-related features (blue); land grids and important roads (red); and other roads and trails, railroads, boundaries, and other cultural features (black). Again, refer to a map’s legend, or go to the USGS website for legend clarification. Names of places, including cities, towns, counties, and other places or prominent landscape features, are shown in a color corresponding to the feature type. Many features and place names are identified with labels, such as Old Faithful Village, Mississippi River, Los Angeles, Substation, or Golf Course.
U.S. Geological Survey and Scales of Other Countries Most countries of the world have established a national map system similar in many ways to that of the United States. While the maps produced by various countries have much in common graphically, unique variations do exist. One should refer to the map legend to better understand the information presented. One of the distinguishing features of various countries’ map systems is whether maps use the metric system of measurement or the imperial (feet and inches) system. The United States is one of the few countries still using the imperial system.
What Is Scale, Why Is It Important, and How Is It Used?
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