Question: How Do You Find The Index Contour?

What is the index contour?

Index contours are bold or thicker lines that appear at every fifth contour line.

If the numbers associated with specific contour lines are increasing, the elevation of the terrain is also increasing..

What 2 types of lines show elevation differences?

Contour lines are used to show elevation on a topographic map. Lines or isolines on a map that connect points with the same elevation. What does each contour line on a map show? Each contour line shows a different elevation.

What information do contour lines provide?

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.

How do you calculate contouring?

Divide the difference in elevation between the index lines by the number of contour lines from one index line to the next. In the example above, the distance 200 is divided by the number of lines, 5. The contour interval is equal to 200 / 5 = 40, or 40-unit contour intervals.

What is the difference in elevation between index contours?

In most topographic maps every 5th contour line is drawn in bold print or wider than other contours. Such lines are called index contour lines. … Contour lines (thinner lines) between index contours are called intermediate contour lines. In the map shown below, the elevation difference between index lines is 100 meters.

How do you read contour lines?

How To Read Contour LinesIndex 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. … Supplementary lines appear as dotted lines, indicating flatter terrain.

Why do contour lines never 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.

What is the space between contour lines called?

Contour lines–usually curved, parallel brown lines–show the shape and elevation of the land by connecting points of equal elevation. … The space between the contour lines is called the contour interval and represents a specific (set) distance.

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.