The difference between contouring and levelling is that
1
contouring focuses on distance measurements while levelling focuses on elevation
2
contouring is an angle measuring operation while levelling is for measuring heights
3
contouring focuses on finding points having a given elevation while levelling is to find the elevation of given points
4
contouring focuses on finding points having a given elevation while levelling is to find the elevation of points having same contour interval