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 viz. buildings, roads, walkways, manholes, utility poles, retaining walls, trees, etc.
A topographic survey is usually performed by professional Land Surveyors with the goal of producing two-dimensional maps which represent three-dimensional components of the landscape. The purpose of a Topographic Survey is to collect survey data about the natural as well as man-made features of the land, and its elevations. The survey shows the relative positions and elevations of both natural and man-made features on a property.
Topographical surveys are also referred as contour surveys and they are always conducted before there is any change in the ownership of the land or even when the property owner is willing to make some changes in the land. The main focus of the topographical surveys is to provide 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.
Drones are now being used with laser scanners, as well as other remote sensors and digital cameras, as a more economical method to scan smaller areas. The possibility of drone remote sensing also eliminates any danger that crews of a manned aircraft may be subjected to in difficult terrain or remote areas.
Every site is different and presents specific risks and challenges. We have shifted from the primitive method of DGPS & ETS (Electronic Total Stations) to the modern innovative method of DGPS, mobile LiDAR and UAV/Drone for medium to huge and complex sites. Here, we establish control points by high precise Survey Grade Differential Global Positioning Systems in static mode, throughout the area to be surveyed. Then we capture 3D point cloud data using our Leica "Pegasus one" Mobile LiDAR mapping system along all motorable & developed roads in the area to be surveyed.
Thereafter, low altitude flying UAV/Drones are used for capturing ground data with sufficient overlaps so as to develop a dense 3D point cloud data. This combined technology gives an accuracy of about +/- 5 cm globally, which is quite good as compared to the speed of Topographic survey. Contours can be generated at required intervals say 0.5 m or 1 m, using this dense 3D point cloud data and drawings are prepared upto the scale of 1:500 sufficient for planning and development of any infrastructure project.