Quick Answer: What Is The Factors Affecting Contour Interval?

What is meant by a contour line?

Contour line, a line on a map representing an imaginary line on the land surface, all points of which are at the same elevation above a datum plane, usually mean sea level..

What does the contour interval 40 feet refer to?

A map’s contour interval is the difference in elevation between two adjacent contour lines (usually 40 feet on 7.5-minute maps and 80 feet on 15-minute maps). Every fifth contour line is printed darker than other lines and is labeled periodically with elevation.

What are the methods of contouring?

Methods of ContouringDirect Methods. It consists in finding vertical and horizontal controls of the points which lie on the selected contour line. … Method of Cross-section: In this method cross-sectional points are taken at regular interval. By levelling the reduced level of all those points are established. … Drawing Contours.

What does it mean when contour lines are close together?

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 other name of contour lines?

A contour line (also isoline, isopleth, or isarithm) of a function of two variables is a curve along which the function has a constant value, so that the curve joins points of equal value.

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 is a contour interval and on what factors does it depend?

Answer. Answer: The contour interval depends upon the general topography of the terrain. In flat ground, contours at small intervals are surveyed to depict the general slope of the ground whereas high hills can only be depicted with contours at larger contour interval.

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 is difference between contour interval and horizontal equivalent?

Explain Terms Used in Contouring….What is the Difference Between Contour Interval and Horizontal Equivalent.S.NoContour IntervalHorizontal Equivalent3In a given map the contour interval is a constantThe horizontal equivalent varies with slope. Closer distance indicates steep slope and wider distance gentle slope2 more rows

What are 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…

What is the importance of contour lines?

The purpose of contour lines is to represent the tridimensional shape of the terrestrial surface on a bidimensional map. Contour lines are the intersection of an horizontal plane parallel to the reference level and the topographical surface to describe. Consequently: Contour lines are always closed curves.

How do you make a contour line?

Contour lines can be created by attributing each point with the lithic count amounts. Note: Overall contour accuracy depends on how well the data used to create the input raster represents the actual surface, therefore it is important to evaluate the data and its purpose to avoid accuracy issues in data representation.

What does the contour interval mean?

A contour line is a line drawn on a topographic map to indicate ground elevation or depression. A contour interval is the vertical distance or difference in elevation between contour lines. Index contours are bold or thicker lines that appear at every fifth contour line.

What are the factors on which contour lines are based?

FACTORS FOR DECIDING CONTOUR INTERVAL The contour interval is kept inversely proportional to the scale of the map. Purpose of the map. The contour interval on a map also depends upon the purpose for which the map is to be utilized. Nature of the ground.

What is a contour index?

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.

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 vertical equivalent?

Vertical Interval is the vertical distance between two contour lines. Horizontal Equivalent is the actual distance between two points on two contour lines. Slope of the land is known as the gradient. … Gradient = Vertical Interval/Horizontal Equivalent.

What is horizontal equivalent in contouring?

The horizontal distance on the earth’s surface between successive contours. The height interval between the successive contours is known as a vertical interval. For a given vertical interval, the smaller the horizontal equivalent, the steeper is the average slope.