For what purpose is contour lines used on a map?

For what purpose is contour lines used on a map?

Contours are imag- inary lines that join points of equal elevation on the surface of the land above or below a reference surface, such as mean sea level. Contours make it possible to measure the height of mountains, depths of the ocean bottom, and steep- ness of slopes. A topographic map shows more than contours.

What do contour lines on a topographic map show quizlet?

Contour lines are used to show elevation on a topographic map. Lines or isolines on a map that connect points with the same elevation….Contour lines rules:

• Contour lines never cross.
• All points on a contour line are at the same elevation.
• The space between contour lines depends.

What is a contour interval on a topographic map?

Individual contour lines on a topographical map are a fixed interval of elevation apart known as a contour interval. Common contour intervals are 5, 10, 20, 40, 80, or 100 feet. The actual contour interval of a map depends upon the topography being represented as well as the scale of the map.

What do the contour lines do as they cross over a stream?

When contour lines cross a stream, they form a “V” that always points uphill. As a general rule, water flows downhill perpendicular to contour lines.

How must contour lines bend on a topographic map to indicate a stream valley?

A contour line that bends to form a V shape indicates a valley. The bend in the V points toward the higher end of the valley; this V points upstream, or in the direction from which the water flows, if there is a stream.

How do you identify contour lines on a map?

Ever noticed those squiggly lines all over your hiking map? Other than the obvious trails and rivers, these squiggly lines are contour lines. Put simply, contour lines mark points of equal elevation on a map. If you trace the length of a line with your finger, each point you touch is the same height above sea level.

How do you read elevation contour lines?

You can figure out the elevation of any point by finding the nearest labeled line, counting the number of lines above or below it, multiplying by the contour interval, and adding or subtracting the result from the nearest marked contour line. The more closely spaced the contour lines, the steeper the slope.

What do dotted contour lines on a map indicate?

Index lines are the thickest contour lines and are usually labeled with a number at one point along the line. This tells you the elevation above sea level. Intermediate lines are the thinner, more common, lines between the index lines. They usually don’t have a number label. Supplementary lines appear as dotted lines, indicating flatter terrain.

What are the lines on a topographic map called?

The thin brown lines snaking around a topographic map are called contour lines. All points along the same contour line are at the same elevation above sea level. Think of a contour line as a closed loop.

What is the distance between contour lines?

The distance between contour lines represents a change in elevation. Many maps are in either a 1:24 000 scale (in the US) or a 1: 25 000 scale (metric); on these maps, the contour interval is 10 feet. (This can be found along the edge of the map.)

What kind of map uses contour lines to illustrate elevation?

A map with contour lines on it is called a topographic map. Topographic maps use a combination of colors, shading and contour lines to represent changes in elevation and terrain shape. Essentially, topographic maps represent the three-dimensional landscape of Earth within the two-dimensional space of a map.