ADVANCED DTM GENERATION USING AIRBORNE LIDAR TECHNIQUE

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Simulations of the hydrological risks and thus the decisions of assessment strategies are crucial in the context of extreme meteorological events due to the consequences of the fast changes in the climate. The remote sensing methods, such as LIDAR backscatter technique are allowing the elaboration of a high precision (5cm vertical and 3 points/m2 horizontal resolutions) Digital Terrain Model (DTM) as basis of the hydrological modeling. In this paper is presented the airborne LIDAR technique, methodology of obtaining the DTM, the usefulness of the DTM outputs for hydrologic applications and the potential application for the Romanian Danube Flood Plain assessment strategy.

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  • « L’environnement est actuellement un sujet incontournable se situant au carrefour des intérêts du monde économique – politique - financier et social avec des implications majeures allant de l’échelle des intérêts individuelles jusque à l’échelle planétaire. La pollution environnementale et le changement climatique, avec leurs conséquences possibles dans le développement des phénomènes extrêmes (incendies, inondations, fonte des glaciers, vagues de chaleur, tempêtes,…) engendrent des déséquilibres économiques et sociales ayant des enjeux majeurs concernent tout individu, institution et nation » Dans ce contexte EnviroScopY SA ( ESYCH) est une nouvelle entreprise crée le 08.03.2006 ayant son savoir faire général dans le domaine des Sciences – Technologies - Management de l’Environnement , son métier dans le domaine de la Qualité de l’Air et sa vocation de créateur tant des Instruments High -Tech de monitoring des paramètres atmosphériques que des Modèles Complexes de Simulation comme aide à la décision des stratégies d’abattement. ESYCH s’adresse aux institutions impliquées de manière responsable dans l’assurance de la qualité de l’air ( et de l’environnement en général) qui ont besoin d’un support spécialisé (conseil), d’un partenaire de projet ou qui cherche de mesures et études avec des instruments et outils de modélisation complémentaires plus représentatives que celle actuelles. Les problématiques de l’ ozone en été et celle des poussières fines en hiver son pleinement visées. Les références de l’ ESYCH sont l’équipe des professionnels reconnus, l’ expérience et les publications attestant déjà l’utilisation avec succès des techniques et des outils proposées sur le terrain dans plusieurs projets effectués dans plusieurs pays. Au partenaire principal l’École Polytechnique de Lausanne (les laboratoires LPAS & EFLUM) s’ajoute un le CSEM (Centre Suisse d’Electronique et Microélectronique) , le parc scientifique de l’EPFL ( PSE ), et autres à l’étranger. Les opportunités de projets se situent tant en Suisse que à l’étranger dans le contexte du changement climatique et sa relation directe avec la pollution de l’air .
  • ADVANCED DTM GENERATION USING AIRBORNE LIDAR TECHNIQUE

    1. 1. ADVANCED DTM GENERATION USING AIRBORNE LIDAR TECHNIQUE A. Covasnianu , M.M. Cazacu, I. Balin contact: adrian.covasnianu@enviroscopy.com 1 st International Symposium of Technical Geography-Cluj Napoca 30-31th of May 2008 INCDD Tulcea
    2. 2. Contents <ul><li>What is LIDAR? </li></ul><ul><li>LIDAR used in applications </li></ul><ul><li>The principle of airborne LIDAR technique </li></ul><ul><li>Short introduction-REELD 2007 campaign </li></ul><ul><li>Flight parameters </li></ul><ul><li>Data-case study- Galati shipyard </li></ul><ul><li>Data processing </li></ul><ul><li>Quantitative data ESULTS </li></ul><ul><li>Flood simulation </li></ul>1 st International Symposium of Technical Geography-Cluj Napoca 30-31th of May 2008
    3. 3. LIDAR ( Li ght D etection and R anging) R ADAR : radio waves are transmited into atmos phere , which spreads a part of the energy back to the radar’s receiver LIDAR : transmits and receives electromagnetical radiation, but of a higher frequency ( from UV , VIZ and IR ) 1. What is LIDAR? 1st International Symposium of Technical Geography-Cluj Napoca 30-31th of May 2008
    4. 4. <ul><li>LIDAR technique can be used in the next applications: </li></ul><ul><li>The measurement of distance and elevation </li></ul><ul><li>Measurement of speed </li></ul><ul><li>Measurement of rotation </li></ul><ul><li>Measurement of chemical and concentration composition </li></ul><ul><li>Remote sensing applications </li></ul>2. LIDAR APPLICATIONS 1 st International Symposium of Technical Geography-Cluj Napoca 30-31th of May 2008
    5. 5. 3. The principle of airborne LIDAR technique Echo signals resulting from different types of targets LIDAR sensors, used for topographic applications operate in the near infrared band. Unlike photogrammetry, LIDAR data collection is not affected by sun angle and does not require collection to be performed in late fall or early spring for leaf-off conditions 1 st International Symposium of Technical Geography-Cluj Napoca 30-31th of May 2008 Airborne Laser Scanner – RIEGL LMS Q560
    6. 6. Airborne Laser Scanner RIEGL LMS Q560 <ul><li>Waveform analysis for unlimited number of target echoes </li></ul><ul><li>High laser pulse repetition rate up to 240 kHz </li></ul><ul><li>High mean measurement rate up to 160 kHz </li></ul><ul><li>High ranging accuracy up to 20 mm </li></ul><ul><li>Interface for smooth integration of GPS </li></ul><ul><li>Eye safe operation at any altitude </li></ul><ul><li>Parallel scan lines </li></ul><ul><li>Compact and rugged design, single power supply </li></ul><ul><li>Wide operating temperature range </li></ul>Range measurement performance Minimum range: 30 m Accuracy: 20 mm Precision: 10 mm Laser Pulse Repetition rate: up to 240 000 Hz Effective measurement Rate: up to 120 kHz at 45 deg scan angle and up to 160 kHz at 60 deg scan angle Laser Wavelength: near infrared Number of targets per pulse: digitized waveform processing: unlimited online monitoring data output: first pulse or last pulse 1 st International Symposium of Technical Geography-Cluj Napoca 30-31th of May 2008
    7. 7. 3. The principle of airborne LIDAR technique GPS corrections in real time from the satelites Laser scanning GPS reference station with double frequency GPS in double frequence GPS navigation system in real time Inertial device 1 st International Symposium of Technical Geography-Cluj Napoca 30-31th of May 2008
    8. 8. 4. Flight parameters  - h - - 2  tan(  /2)  h - Overlapping <ul><li>0 ft < h < 1500 ft (1500 ft) </li></ul><ul><li> = 60° to 80° (60 ° ) </li></ul><ul><li>Overlapping between 10% and 50% (20 %) </li></ul><ul><li>Speed : 60kts (52kts) </li></ul> Between 1 and 10 points/m² (4,5 points/ m² ) 1 st International Symposium of Technical Geography-Cluj Napoca 30-31th of May 2008
    9. 9. Data processing schematics <ul><li>The steps of the airborne LIDAR mapping are: </li></ul><ul><li>Recording the topographical data </li></ul><ul><li>Transforming the data into xyz files (ASCII files) containing values of latitude, longitude and elevation in WGS 84 coordinate system </li></ul><ul><li>Creating a 3d point cloud and in the end the DEM </li></ul>1 st International Symposium of Technical Geography-Cluj Napoca 30-31th of May 2008
    10. 10. 4. Brief history <ul><li>Due to the floods from spring 2006, Environmental Ministry and Sustainable Development from Romania decided to launch a study which will lead to reestablish the line defenses of the localities (the new ones), so that the next major floods do not put in danger human’s life. </li></ul><ul><li>The solution= A Digital Map of the Danube River and Danube Delta </li></ul>1 st International Symposium of Technical Geography-Cluj Napoca 30-31th of May 2008
    11. 11. REELD ( E conomical and Ecological Reconstruction of the D anube Riverside ) campaign -2007 <ul><li>covers an area of 530.000 ha </li></ul><ul><li>the band of the DTM is variable (from 1 km to 80 km) </li></ul><ul><li>extends over 1075 km (total length of the Danube river in Romania) </li></ul>Technical details of the campaign 1 st International Symposium of Technical Geography-Cluj Napoca 30-31th of May 2008
    12. 12. Airborne LIDAR PartenAvia (Apei SA) 4-5 pts/m2 1 st International Symposium of Technical Geography-Cluj Napoca 30-31th of May 2008 DTM-LIDAR flight parameters Value Flight alltitude 450 m Speed flight 45 m/s Band width 520 m Lateral coverage b ands/Overlapping 20% Distance between bands 415 m Laser emmision frequency 65 kHz Scanning angle 60 0 (+/ - 10 0 ) Scanning frequency 75 Hz (Standard deviation) total planimetric precision of the measured laser points 20 cm Medium density of laser points 2.8 pts / m 2 Medium distance between laser points (flight direction and perpendicular) 0,6 m
    13. 13. Flight tracks along the Danube river-Romanian section of the river We are here! 1 st International Symposium of Technical Geography-Cluj Napoca 30-31th of May 2008
    14. 14. Flight tracks 1 st International Symposium of Technical Geography-Cluj Napoca 30-31th of May 2008
    15. 15. 1st Internation Symposium of technical geography-CJ 30-31th of May 2008 Examples from the REELD 2007 campaign Case Study: REELD EXAMPLE – May 2007
    16. 16. Case Study: REELD EXAMPLE – May 2007 GALATI SHIPYARD Digital terrain model (DTM) Pure ground TULCEA County Buildings Danube planted forest Defence Dam Trees
    17. 17. TOPOGRAPHICAL PROFILES -EXAMPLES 1 st International Symposium of Technical Geography-Cluj Napoca 30-31th of May 2008
    18. 18. QUANTITATIVE DATA Profile -Channel (transversal) Profile Danube (transversal) Profile Channel (longitudinal) 1 st International Symposium of Technical Geography-Cluj Napoca 30-31th of May 2008
    19. 19. More data… Bands from LIDAR: length of 15 km and width of 500 meters each The intensity of LIDAR signal’s echo ( „albedo” ) . D a n ube - black colour in the left, that means lack of LIDAR signal. Altitude- Danube in black colour, the higher areas – green to red. Altitude class- low vegetation DTM- see clearly the Danube, the hills
    20. 20. Balta Crapina - localisation 1 st International Symposium of Technical Geography-Cluj Napoca 30-31th of May 2008
    21. 21. 9. Simulation of hydrological flood- Balta Crapina Crapina Area- Courtesy of INCDD Tulcea
    22. 22. Conclusion <ul><li>Airborne LIDAR mapping is quick and very precise way to produce high-resolution digital elevation data for flood risk management. This LIDAR data set allows planners and hydrologists to predict flood extends and plan remedial strategies. </li></ul><ul><li>Perspectives: 3D cities, projection of highways and high voltage transmission . </li></ul>1 st International Symposium of Technical Geography-Cluj Napoca 30-31th of May 2008
    23. 23. Special thanks to: 1 st International Symposium of Technical Geography-Cluj Napoca 30-31th of May 2008 Sintegra Company <ul><li>Aéro Photo Europe Investigation </li></ul>Danube Delta National Institute for Research and Development-Tulcea INCDD Tulcea

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