We begin with identifying Sites of Interest (SOIs) through the digital historical GIS project “The Battle of Hong Kong 1941: The Spatial History Project” ……. and then, we employ our GEO-spatial and GEO-morphological technologies!
The GEO-spatial and GEO-morphological technologies: We identified points of interest. In a search range of 300m, we generated 3D digital terrain models (DTM) (= the ground) by point-cloud data from airborne laser scanning (supported by CEDD of HKSARG) and post-processed by red relief image map (RRIM) algorithm. The models remove the forest on top of the DTM, and reveal the abnormal man-made hidden WWII structures in 3D and bring the public back to exactly where they are located. Next, we explored the SOIs and made a 3D-model of the WWII structures in the field by terrestrial laser scanning and close-range photogrammetry. Both were geo-referenced by precise global navigation satellite systems (GNSS) to make the 3D models now complete for historians to tell the stories.
The GEO-physical technologies: We study not only the hidden features by geo-spatial tech but also the buried features by ground penetrating radar (GPR), drone-infrared thermography (IR), drone-magnetometer and drone-metal detector. These technologies measure contrast of electrical, temperature and magnetic field, respectively, that led to the lost hints of WWII structures invisible in the DTM. Results will be shared soon, stay tuned!