THE USE OF LIDAR REMOTE-SENSING DATA PUBLISHEDC. POPESCU*, A. ŞMULEAC*, M. HERBEI*
Abstract: This paper deals with LIDAR (Light Detection and Ranging), a laser-scanning technology with a definite characteristic: it can acquire, process and deliver data in digital format. LIDAR is an optical remote-sensing method of extracting information about remote objects by measuring the properties of light scattered on the objects. LIDAR provides unlimited potential in infrastructure projects and is applied in an increasing range of fields. LIDAR uses the same principle as RADAR, the difference between the two methods lying in the electromagnetic radiation wavelength. LIDAR is based on three systems: laser scanning for precise distance measuring, the positioning system (GPS) and the Inertial Measurement Unit (IMU) for orientation measuring. To obtain data on field topology, the LIDAR system receives laser impulses in the 1040–1060 nm wavelength range (near infrared band).The advantage of this technology is that the laser beam penetrates the vegetation, no matter how dense it may be. The present paper uses 3D satellite images and their applications. It also speaks about the main aspects of altimetry data quality assessment of the Digital Terrain Model (DTM) obtained through laser scanning. The altimetry data were collected in the Vârful Căpăţînii area, in the south, and Zănoaga, up to the limit of Gorj and Hunedoara Counties in the north. The route covers about 4 km and the ground level is between 1474 m at Zănoaga and 1565 m above the Black Sea level at Vârful Căpăţînii. LIDAR technology helps creating numerous data sets that are useful for a wide range of applications. The quantitative and qualitative data obtained with LIDAR technology provide additional information about the condition of the vegetation, the quality of the environment (pollution), drainage basins (flood impact estimation), special constructions (pipes, bridges, high voltages transmission lines), studies about forest fire risk, infrastructure management (road, railway and telephone networks) and land inventory. The LIDAR-type satellite images were used with Global Mapper versions 15.2 and 16.1. For the 15.2 version we used the data set "ASTER GDEM (Global Digital Elevation Model) Worldwide Elevation Data (1.5 arc-second resolution). For the 16.1 version we used the data set "ASTER GDEM (Global Digital Elevation Model) version 2 – Worldwide Elevation Data (1 arc-second resolution), which was released on October 17th 2011. The first version was released in June 2009 and was generated with stereo pair images collected with ASTER instruments. The ASTER GDEM cover is from latitude 83º north to 83º south and includes 99% of the Earth surface.
Key words: LIDAR, 3DModel, GPS, ASTER GDEM2, DTM, Global Mapper, IMU