What Is A Supplementary Contour Line?

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.

The area of the map above boxed in orange shows an area that has a fairly steep slope, while the area boxed in purple is a relatively flat area..

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.

Can 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.

How do you read contour lines on a site plan?

Closely spaced contour lines indicate steep slope. Widely spaced contour lines indicate gentle slope. Equally spaced contour lines indicate uniform slope. Closed contour lines with higher elevation towards the centre indicate hills.

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.

How do you do a contour analysis?

GENERAL RULES OF CONTOURING: Prepare to contour. A. Search for continuity (time and space) on the weather map B. … Drawing the map. A. Use a pencil !! … Review your map. A. Do a gross check of isopleths for accuracy B. … Your map is now ready for interpretation!

What exactly does a contour line show?

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. The diagram illustrates how contour lines show relief by joining points of equal elevation.

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.

Why do we use 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.

What is meant by contour interval?

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

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…

How do contour lines work?

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. … In order to keep things simple, topographic maps show lines for certain elevations only.

How do you calculate contour lines?

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 elevation difference between contour lines?

The elevation difference between two adjacent contour lines is called the contour interval (CI). Usually the contour interval is noted on the map legend. 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.