The contour interval is printed in the margin of each U.S. Maps in mountainous areas may have contour intervals of 100 feet or more. Note: Purple can be used to show information added over the original map detail (updates). A map of a relatively flat area may have a contour interval of 10 feet or less. Grey: on the back of the map for a glossary of terms, and abbreviations.Green: wooded areas, orchards, and vineyards.Blue: lakes, streams, falls, rapids, swamps and marshes, names of bodies of water and watercourses, magnetic declination and UTM (Universal Transverse Mercator) grid information.Brown: contour lines, spot elevations, sand and eskers.Orange: unpaved roads and unclassified roads and streets.Red: paved roads, highway numbers, interchange exit numbers, certain symbols, names of major transportation routes and a red tint for urban development.Black: buildings, railways, power transmission lines, geographical names (toponymy), certain symbols, geographic coordinates, precise elevations, border information, and surround information.On a polychrome map, each feature is represented by a colour. Use the contour interval and the map scale to measure the steepness between the marked points on each map. 1:50 000 National Topographic System map sample - 058F11 Resolute, Nunavut Feature types on a polychrome topographic map
