47) What term is given to the graphical representation of the features on the earth surface as projected on a horizontal plane in surveying?

48) Which term is used for representing surface of the earth on a small scale in surveying?

49) Which method of surveying the area is sub divided into network of triangles?

50) Which survey deals with the collection of the details of cyclonic affected area, flooded area etc, is done by aeroplane in air?

51) Which survey deals with the star's in the sky?