A topographic survey determines the location of natural and man-made features (such as buildings, improvements, fences, land contours, trees, streams, etc.) of the land along with its elevations. This type of survey may be required by a government agency but it is mostly used by engineers and/ or architects for the design of improvements or developments on a site.
In other words, a topographic survey or contour survey provides you with the exact figures of the size, height, position of the different changes that have occurred in course of time with regard to their presence of their natural existence. Sometimes, these surveys are also used for the formulation of an optimal plan for drainage, ditches, grading and other features.