New Delhi, Dec 7 : The National High Speed Rail Corporation Limited will adopt light detection and ranging survey (LiDAR) technique for the 800-km Delhi-Varanasi high speed rail (DVHSR) corridor project. This will be the second time that NHSRCL will be suing the LiDAR technique for a project in India. NHSRCL spokesperson Sushma Gaur said that the agency will be adopting LiDAR technique using laser-enabled equipment mounted on a helicopter for conducting ground surveys for the preparation of Detailed Project Report (DPR)A for the proposed Delhi-Varanasi HSR corridor. She said the alignment or ground survey is a crucial activity for any linear infrastructure project it provides accurate details of areas around the alignment. This technique uses a combination of Laser data, GPS data, flight parameters and actual photographs to give accurate survey data. "Based on the findings of the survey, designing of the vertical and horizontal alignment, structures, location of the stations and depots, land requirement for the corridor, identification of project affected plots/structures, right of way etc are decided," she said. She further stayed that the aerial LiDAR survey technique, for the first time for any railway project in India, was adopted for the 508 km Mumbai-Ahmedabad High Speed Rail (MAHSR) corridor primarily because of its high accuracy. She said that the ground survey using aerial LiDAR for MAHSR alignment was done only in 12 weeks against the 10-12 months if had been done through traditional survey methods. "Keeping in mind the magnitude of the project and adhering to the timelines to submit the DPR of DVHSR corridor, the ground survey using aerial LiDAR technique has already started," she said. Reference points on the ground have already been marked and data collection through equipment mounted on a Helicopter will commence from depending of the weather conditions in a phased manner. The requisite permissions from the Ministry of Defence for flying the Helicopter have been received and the inspection of the aircraft and equipment are underway, she said. The proposed Delhi-Varanasi HSR alignment covers mixed terrains including densely populated urban and rural areas, highways, roads, ghats, rivers, green fields etc, which makes this activity more challenging. The NHSRCL has been entrusted with the work for preparing DPR for the Delhi-Varanasi HSR Corridor by the railway ministry. /IANS