Methods of Contouring(2+ Method)

Contouring in surveying refers to the process of determining and representing the elevations of points on the Earth’s surface.(Methods of Contouring)

It’s crucial for creating accurate topographic maps and understanding the terrain. Here are the main methods of contouring used in surveying:

Direct Surveying Method:

Levelling:

  • This method involves using a surveying instrument called a level to measure height differences between points.
  • It is used to establish a series of benchmark elevations, from which contour lines can be interpolated.

Indirect Surveying Methods:

Photogrammetric Contouring:

  • Utilizes aerial photography and photogrammetry techniques to determine elevations.
  • Aerial photographs are analysed to create a digital elevation model (DEM) from which contour lines are derived.

Lidar (Light Detection and Ranging):

  • This method uses laser pulses from an aircraft or satellite to measure distances to the Earth’s surface.
  • Lidar data is processed to create highly accurate DEMs and contour maps.

GPS (Global Positioning System):

  • GPS receivers can used to determine the elevations of survey points.
  • When combined with ground control points, GPS surveys can contribute to contour mapping.

Interpolation Methods:

Digital Terrain Models (DTM):

  • Based on the data collected from direct or indirect methods, DTMs use interpolation algorithms to estimate elevations between measured points, creating a smooth representation of the terrain.

Contouring Software:

  • Various software packages are available that automate the process of contour generation from survey data, whether collected through direct leveling, photogrammetry, Lidar, or GPS.

Manual Contouring (Traditional Method):

  • In some cases, especially in smaller-scale surveys or where digital data not available, contour lines may manually sketched based on field observations and direct measurements.

Each method has its advantages and limitations, depending on factors such as terrain characteristics, required accuracy, and available resources.

Modern surveying practices often integrate multiple methods to achieve the most accurate and detailed contour maps possible.

Thank You.

Video Tutorials Here…

Leave a Comment

Share via
Copy link
Powered by Social Snap