In contour, we details discuss about use of contour, contour interval, properties of contour lines, ridge & valley line, overhanging cliff, vertical cliff. Etc.

In levelling, we are details discuss about elevation & altitude, reduced level, mean sea level, bench marks(B.M), horizontal line, vertical line, level line, back sight reading, fore sight reading, intermediate sight reading, method to find reduced level, height of instrument, rise and fall method, inverted staff, correction required in levelling work, distance of visible horizon, reciprocal leveling, collimation error, angular / inclination error, sensitivity of bubble tube, the sensitivity of level tube increases with?.