Methodology for the Topographical Survey work for Land Survey
Identifying the Boundary corners of the Proposed Project
If the proposed project area are covered few villages and having Hundreds of individual survey nos., with the help of combined village map provided by the revenue departments and with the help of revenue surveyors, we can identify the all Corners of the boundary.
Fixing of Horizontal Control Points
The Horizontal Control points will be fixed by the DGPS on the permanent locations on all major corners of the area and also on the center of the proposed project area. The secondary control points shall be fixed on available permanent location by Total Station.
Traverse
Total Station having 5” or more accuracy shall be used for this activity.
The Traverse loops to be connected to DGPS pairs and closing error to be calculated.
The error shall be adjusted on all points fixed by Total Stations thru Bowditch Rule.
The accuracy will be 1:20,000.
Fixing of Vertical Control Points.
The GTS level Fixed by the Survey of India (SOI) shall be identified by the help of the Government Department. The same shall be transferred to the Project site by using Auto Level and will be connected to all the control points fixed by GPS and By Total Stations. The fly levels shall be run as Rise and Fall method and will be closed at starting points. The accuracy of the fly shall level shall be 6√k,where K is no of Km of fly level loop.
Detail survey
Total Station shall be used by this assignment. This activity shall be completed based on the points fixed by the Traverse. All the Road Network inside the project boundary shall be mapped with its Levels. The block levels shall be picked up at an interval of 25m in plain areas. And levels shall be picked up where ever any abrupt changes are available in ground. The outlets (weir) of the Tank/ponds shall be mapped with it Levels. All Utility lines, both overhead and underground such as Electrical Poles, Telephone Poles, Lamp Poles and any other Private/Unauthorized utility Poles with their routing network. Water / Sewerage / Oil / Gas Pipe Lines with diameter and material of the pipe. Manholes with their actual size and shape (ex. rectangular or square or circular) Special emphasis shall be laid in identifying and mapping of all religious places - temples, temple mast, mosque, church; its locations. Locations of drain clearly identifying the type (Built-up / Earthen, Rectangular / Trapezoidal etc., and whether Open / Closed), width of drain (waterway width and wall width in case of built-up drain) including the beginning and end of drain. While surveying the existing drains, care shall be taken to take the top and bottom points of the drain to get the true contour and shape of the drain. All water features such as ponds, tanks, lakes, streams, canals and wells etc shall be mapped. Mapping of all bridges and culverts along the fishing villages shall include location (chainage), and reference number, width of bridge / culvert (width of slab or diameter of pipe, no of pipes/spans), course of water path, skew of bridge / culvert, span arrangement. It will also include the Invert levels, High flood level, Bed Levels and direction of water flow.
Survey reports and drawings.
The contour map shall be prepared at an interval of 0.50m, Based on the blocks levels picked by total station. The Survey report shall consist of topographical survey drawings (soft), field book / level book, and all relevant details of the survey. Final coordinate and elevation list of survey stations in Excel format.
Accuracy of the Survey