17) What is the process of placing the contour lines proportionally between the plotted ground point is?

18) What is the distance between A and 42 m contour given that the distance between A and B is 10m and have reduced levels 41.3 and 43.8 m, contour interval 1m?

19) Which method of interpolation of contour is done with the help of tracing cloth?

20) Which contour line is usually thicker than the rest in a contour map?

21) Which method of contouring is unsuitable in hilly area?