A geological survey is the systematic investigation of the geology beneath a given piece of ground for the purpose of creating a geological map or model.

Topographic Surveys are used to identify and map the contours of the ground and existing features on the surface of the earth or slightly above or below the earth's surface (i.e. trees, buildings, streets, walkways, manholes, utility poles, retaining walls, etc.).  If the purpose of the survey is to serve as a base map for the design of a residence or building of some type, or design a road o[..]

When We measure the height difference of road in varies places please Watch the video is completly

A longitudinal survey is a correlational research study that involves repeated observations of the same variables over long periods of time, often many decades. It is often a type of observational study, although they can also be structured aslongitudinal randomized experiments.