What are the factors affecting the choice of contour interval?

What are the factors affecting the choice of contour interval?

The Contour Spacing Depends On The Following Factors:

• The Scale of The Map. The contour interval is inversely proportional to the scale of the map.
• Nature of The Ground.
• Purpose and Expansion of the survey work.
• Time available and Eligible Expenses for field and office work.

How is contour interval selected?

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. Pick two contour lines that are next to each other and find the difference in associated numbers.

Why do cartographers only name some of the contour lines on maps?

Labeling contour maps Labels are a critical component of elevation maps. A properly labeled contour map helps the reader to quickly interpret the shape of the terrain. If numbers are placed close to each other, it means that the terrain is steep.

What are the 3 rules for contour maps?

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.

How does accuracy affect the choice of contour interval?

Accuracy need of surveying work also decide the contour interval. But in case of location surveys where the desired accuracy is less, higher contour interval should be used. Time and Cost. If the contour interval is small, greater time and funds will be required in the field survey, in reduction and in plotting the map …

What is contour map surveying?

In land surveying 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.

What kind of maps do cartographers make?

Cartographers make many different types of maps, which can be divided into two broad categories: general reference maps and thematic maps. General reference maps show general geographic information about an area, including the locations of cities, boundaries, roads, mountains, rivers, and coastlines.

What is contour gradient surveying?

A line marked on the ground surface at a given constant slope.

How do you determine the contour interval of a map?

FACTORS FOR DECIDING CONTOUR INTERVAL. Contour interval on a map is decided on the following considerations: 1) Scale of the map. The contour interval is kept inversely proportional to the scale of the map. Smaller the scale of the map, larger the contour interval.

What is the height difference between contours called?

The height difference between contours is called the contour interval. In the simplest system there is a single value assigned to the contour interval. The choice of contour interval depends upon several factors. First, the accuracy and completeness of the landform data must be determined.

What are contour lines on a map?

Contour lines are imaginary lines which represent the intersections that arise from horizontally slicing up landforms into equal vertical intervals like a layer cake. Figure 10. Imhof defines them as, “… lines on the map depicting the metric locations of points on the earth’s surface at the same elevation above sea level.”

What are the advantages of contours in landscape painting?

The new method was the use of contours and depth contours or isobaths. Contours have the immense advantage over other methods of terrain depiction because they record and convey the geometric form of the terrain including elevations and the angles and directions of slopes.