How do you find the index contour?
On most maps, each fifth contour line, shown as a heavier or darker line, is an index line or index contour. These index lines will be marked with their elevation. Find the elevations of two adjacent index lines. The highest number shows the uphill rise.
What is an index contour and why are they important?
An index contour line on a topographic map is a darker, or bold line that usually occurs every fifth line on the map. These index lines have the specific elevation written along with them to make reading the topographic map easier.
What is the difference between index contour and intermediate contour?
The elevation difference between two adjacent contour lines is called the contour interval (CI). Such lines are called index contour lines. They are usually labeled with their corresponding elevations. Contour lines (thinner lines) between index contours are called intermediate contour lines.
Why do we need index contour lines?
To make topographic maps easier to read, every fifth contour line is an index contour. Because it’s impractical to mark the elevation of every contour line on the map, the index contour lines are the only ones labeled. The index contours are a darker or wider brown line in comparison to the regular contour lines.
What is an index contour and how do you recognize it?
A contour line shown on a map in a distinctive manner for ease of identification, being printed more heavily than other contour lines and generally labeled with a value (such as figure of elevation) along its course.
What do you understand by index contours and intermediate contours?
Explanation: Such lines are called index contour lines. They are usually labeled with their corresponding elevations. Contour lines (thinner lines) between index contours are called intermediate contour lines.
What is grade contouring?
Contour grading means grading which creates, or results in, land surfaces which reflect the pre-graded natural terrain or that simulates natural terrain, i.e., rounded non-planar surfaces and rounded, non-angular intersections between surfaces.
Why is index contour different from other contour lines?
The index contour represents the vertical scale on a map region by a thick solid line with the various elevations printed on it. Thinner solid lines, called intermediate contours, are used to depict lesser elevations that are referenced to the height information provided by the map’s legend.
What is the definition of an index contour?
An index contour is one of the ways that vertical dimension, or vertical scale, is demonstrated on a topographical map.
How are index contour lines different from other contour lines?
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 index contour lines?
index contour line A contour line accentuated by a heavier line weight to distinguish it from intermediate contour lines. Index contours are usually shown as every fifth contour with their assigned values, to facilitate reading elevations.