# What Do Contour Lines Indicate?

## What do contour lines tell us?

In cartography, a contour line (often just called a “contour”) joins points of equal elevation (height) above a given level, such as mean sea level.

A contour map is a map illustrated with contour lines, for example a topographic map, which thus shows valleys and hills, and the steepness or gentleness of slopes..

## Why are contour lines used?

Tell students that by reading contour lines, they can measure the steepness of a hill, the height of a mountain, and even the depth of a lake or ocean. Have students pinpoint a place where the contour lines are close together. Explain that the close lines mean the elevation is changing rapidly; those are steep places.

## What do close contour lines indicate?

Contour lines that are relatively close together indicate a slope that is fairly steep. Contour lines that are further apart indicates a slope that is relatively flat.

## What is the space between contour lines called?

The space between the contour lines is called the contour interval and represents a specific (set) distance. If the contour interval is 50 feet, the vertical space between the two contour lines is 50 feet.

## How do contour lines indicate elevation?

Contour lines are lines drawn on a map connecting points of equal elevation, meaning if you physically followed a contour line, elevation would remain constant. Contour lines show elevation and the shape of the terrain. They’re useful because they illustrate the shape of the land surface — its topography — on the map.

## What are the 5 Rules of contour lines?

Rule 1 – every point of a contour line has the same elevation. Rule 2 – contour lines separate uphill from downhill. Rule 3 – contour lines do not touch or cross each other except at a cliff. Rule 4 – every 5th contour line is darker in color.

## What are the 3 types of contour lines?

There are 3 kinds of contour lines you’ll see on a map: intermediate, index, and supplementary.Index lines are the thickest contour lines and are usually labeled with a number at one point along the line. … Intermediate lines are the thinner, more common, lines between the index lines.More items…

## Why can’t contour lines cross?

Contour lines can never cross one another. Each line represents a separate elevation, and you can’t have two different elevations at the same point. … Moving from one contour line to another always indicates a change in elevation.

## What is a depression contour line?

A closed contour, inside of which the ground or geologic structure is at a lower elevation than that outside, and distinguished on a map from other contour lines by hachures marked on the downslope or downdip side.

## How do you tell if contour lines are going up or down?

Remember contour numbering reads up hill – in other words the top of the number is uphill and the bottom is downhill. Also remember the closer contour lines are together, the steeper the slope.