This method is suitable for road, railway and canal surveys. In here, consider X, Y and Z as the center line of the road, railway or canal like what is shown in the figure below

The lines are drawn by cartographers to approximate the contours on the area that are inaccessible on the ground

shows the height, depth, size and location of any man-made or natural features on a given land area, as well as the changes or contours in elevation throughout the area

The work is then plotted on plan and the required contour line is drawn by the process called the interpolation.

It is the vertical distance between any two consecutive contour

In this method, a tacheometer or theodolite is utilized to determine the horizontal distances and elevations of points.

These are drawn to represent low spots like excavations around which contours close. The symbol used is the index or intermediate contour to which ticks are drawn perpendicular to the contour line on the downhill side.

Also known as block contouring. In this method, the area to be surveyed is divided into a number of squares of size 5 to 20 meters, depending upon the nature of ground and contour interval required

It refers to the constant vertical distance between two adjacent contour lines. must be always consistent within the limits of the map

These are lines in between index contours that are drawn in lighter weight. They conform to the contour interval specified for the map.

The process of tracing contour lines on the surface of the Earth.

An imaginary outline of the terrain obtained by joining points of the same elevation. It is generally labeled with a value (such as figure of elevation) along its course.

The physical configuration of the earths surface, depicted on a topographic map by contour lines and spot elevations.

refers to the configuration or shape and roughness of the ground. Information like these can be found on a topographic map which is one of the outputs of topographic surveys.

Also called as auxiliary contours which are used to show certain portions of the map area that are so flat or level to which the contours are too far apart

A map that shows contour lines. It gives idea of the elevations of the surface features as well as their relative positions in plan, which serves the purpose of being a plan and a section.

It is a bold or thicker line that appears at every fifth contour line.

It is the horizontal distance between two consecutive contour lines measured to the scale of the map.

An imaginary line on the ground surface joining the points of equal elevation which depicts the relief of terrain in a two-dimensional plan or map.

A point on a map where height above mean sea level is noted, usually by a dot and elevation value. It is shown wherever practical (road intersections, summits, lakes, large flat areas and depressions).

It involves finding points on the ground with the value of the required contour. Then, these points are marked with pegs and are plotted on the map using plane table. This method is much lower compared to its counterpart and it is not suitable for large areas.