1st LiDAR mission

 

The first mission planning across the area of Kalochori, western of Thessaloniki, with3D Lidar data acquisition along with very high resolution color (RGB) imagery was organized.  The date of the Lidar mission was Friday the 2nd of May 2014 covering a 25km2 flight plan over the examined area while aerial photography acquisition was performed on 11/05/2014. Upon the issuance of the proper flight permission from the Hellenic National Defence General Staff flight missions were scheduled based on high resolution cloud coverage meteo forecast on 3 hours time intervals from Meteo Lab of the University of Athens. Flight Planning for both sensors was conducted using modern software tools allowing best fit to the geometry and terrain relief of the area. Flight & Sensor Control Management System provided precise flight guidance, an intuitive interface for sensor operation and data quality control during laser and imagery data acquisition. With the use of Leica ALS60 Airborne Laser Scanner, Multiple Pulses in Air (MPiA) sensor there was production of High Density Surface Models (DSM) and DTM at a 1x1 m grid spacing. The process for resolving the lidar trajectories and the computation of the point clouds produced a highly accurate DSM, and has generated realistic 3D+ environments and Info Clouds containing elevations. The combination of DSM/DTM with Airborne Color Imagery acquired with the Z/I DMC gave accurate orthomaps production. The imagery from the DMC native 1:1 color resolution (RGB) was ready for the exploitation process within the end-to-end workflow with use of GPS/INS. After post-processing, the imagery was brought into all stages of the photogrammetric workflow – aerotriangulation and orthorectification at pixel size 0,1m at engineering-scale accuracy. Precise sensor stabilization during camera exposure was essential for good quality, no matter the sensor used. The post-processing has used the concurrent data of the 2nd May from the two GPS GNSS base stations of the project and the 57 GCP measured with GPS GNSS. It was a very dense and accurate GPS campaign in the area of Kalochori. The 3D city model of the broai region obtained from the LiDAR data will allow compilation of a building stock inventory in terms of structural height and plan dimensions. The latter will be utilized for investigating seismic response of structures as affected by soil-structure interaction within a future stage of the INDES-MUSA project.