LESSON 51

• LOCATING & PLOTTING OF CONTOUR LINES is one of the major steps involve in the construction of a topographic map.
• The process of locating contour lines proportionally on the map between points is termed INTERPOLATION
• METHODS PF LOCATING CONTOUR LINES:

  BY ESTIMATION

  RUBBER BAND METHOD

  ANALYTICAL METHOD

  TRIANGLE AND SCALE METHOD

  TEMPLATE METHOD
• BY ESTIMATION This method is suitable on small scale maps where the ground form is not too irregular
• ANALYTICAL METHOD Arithmetical computations are employed where high accuracy is desired in locating contour lines. This method is well suited for drawing large-scale maps
• CONTOUR TEMPLATE It consists of series of equally spaced parallel lines that are drawn on a transparent film or paper using specified scale.
• CROSS PROFILE METHOD is principally used in locating contours along a route or other narrow area of terrain.
• CONTROLLING POINT METHOD considered to be one with the most universal application.
• COORDINATE METHOD One way of locating and plotting the contours of a given area is to utilize a grid or coordinate system.
• TRACE CONTOUR METHOD one of the most accurate and direct procedure of locating contours
• Early pioneers of photogrammetry in the Philippines is BLCGS. What does it stands for?

  Bureau of Lands and the Coast and Geodetic Surveys