The purpose of a topographic survey is to show the ground elevations and existing features located on a parcel of land. Sufficient data is collected to enable the generation of elevation contours and to establish drainage patterns on the subject property. The locations of above-ground and underground utilities are usually shown on the survey. The location of flood-prone areas (as determined by FEMA) are also shown on the survey. Topographic surveys are most often used for engineering and design purposes.