INTEGRATED GEOPHYSICAL AND REMOTE SENSING STUDIES ON GROTTA GIGANTE SHOW CAVE (TRIESTE ITALY) P. Paganini, A. Pavan, F. Coren, A.

Transcription

1 INTEGRATED GEOPHYSICAL AND REMOTE SENSING STUDIES ON GROTTA GIGANTE SHOW CAVE (TRIESTE ITALY) P. Paganini, A. Pavan, F. Coren, A. Fabbricatore

2 Aerial lidar survey - strumentation Piper Seneca II - PA34 200T, property of OGS, has been modified for the installation of strumentation, with a camera hatch 60 x 20 cm, in the bottom of the fuselage.

3 Aerial lidar survey - strumentation Hyperspectral sensor Aisa Eagle 1k Digital camera EOS 1Ds Mk iii Laser sensor Riegl LMS-Q560

4 Aerial lidar survey - strumentation Laser scanner RIEGL LMS-Q560 Scan speed: pt/s Max range: m Precision: 10 cm Field of view: 60 Riegl LMS-Q560 laser sensor Hard Disc recording system

5 Aerial lidar survey - principles Laser scanning system is made by four principal components: Laser Ranger; Positioning Unit (GPS) Inertial Unit PC, for data recording

6 Aerial lidar survey - principles Laser has a beam aperture of 0.4 mrad, which means 0.3 m 800 m AGL. System records the first, the last and up to two intermediate pulses. This allows to calculate: - Vegetation height - Ground height

7 Aerial lidar survey - principles First pulse Second pulse Third pulse Fourth pulse All pulses together

8 Aerial lidar survey data processing Ground GPS (master) Air GPS (rover) Data acquisition Inertial data Laser data Processing Calibration OUTPUT Classification Final Output (ground, DTM, DSM, )

9 Aerial lidar survey - outputs La classificazione del dato laser DSM DTM

10 Aerial lidar survey - outputs Grotta Gigante 820 m 1220 m Survey area: Points acquired: Point density: 1 km2 15 mln 15 p.ts/m2

11 Aerial lidar survey data visualization trees building cars Points on ground surface Points NOT on ground

12 Aerial lidar survey data visualization doline Digital Terrain Model (DTM)

13 Aerial lidar survey data visualization entrance exit Colours Building Rendering by vectorialization class intensity ortho images

14 Photographic system Photographic system ic composed by a digital camera 20 Mpxl, connected to a positioning and inertial system. In this way it is possible to precisely determinate the position and attitude of the camera, at every shooting istant. Pictures taken by plane must be processed and each pixel of the image has to be referred to a topographic surface. For this purpose is used a Digital Terrain Model, made from airborne laser scan data.

15 Photographic system Pictures are acuired in strips, projected in order to have a specific ground pixel on the final image. It is possible to obtain images with 10 cm of pixel, or even less.

16 Photographic system Ortofhoto Le immagini vengono prima raddrizzate utilizzando l informazione del sistema di navigazione e del modello digitale del terreno. Succesivamente vengono mosaicate, cioè unite per formare l ortofoto piano finale.

17 Photographic system

18 Total Station survey Topographic overview of the survey area Polygonal for laser scanning stations Georeferentiation of targets Georeferentiation of point cloud

19 Total Station survey - strumentation TOPCON IS Photo Fieldbook: 360 panoramic images Intelligent Scan: automatic recognition of the point in the cloud. Image Drive: visually operated using the controller icontrol: remoted operated, using WiFi devices or compatible controllers. 2 integrated cameras: wideangle and optical zoom 30x.

20 Terrestrial lidar survey - principles Similar to a motorized total station (million of points in few minutes); Calculation of laser pulse time flight; Angular precise measurement, given by mirror rotation; Point cloud acquired in a local coordinate system.

21 Terrestrial lidar survey - strumentation TOPCON GLS 1500 Wireless LAN & USB connectivity Biaxial compensator Scan speed: p.ts/sec Max range: % reflectivity % reflectivity Accuracy: 150m Data storage on SD card Precise Scan Technology RIEGL LMS-Z420i Scan speed: p.ts/sec Max range: m Precision: 10 mm FOV: 80 vertical, 360 orizontal Integrated metric camera LEICA HDS6000 Scan speed: p.ts/sec Max range: 79 m Precision: 6 mm FOV: 310 vertical, 360 orizontal

22 Terrestrial lidar survey survey properties 2 operating team, contemporary acquiring with 3 terrestrial laser scanners; 10 days of survey, total 100 h of acquisition; > 1 km of polygonals, for the topographic overview of the survey area; > 70 terrestrial laser scanner stations; > 4.5 billions of points acquired; 5 mm precisions on detailed scans (@150 m); medium point cloud density: p.ts/m2.

23 Terrestrial lidar survey overview Ortophoto 10 cm entrance Overlay CTR 1:5000 exit Overlay laser survey

24 Terrestrial lidar survey data visualization

25 Terrestrial lidar survey data visualization Entrance level

26 Terrestrial lidar survey data visualization Entrance level 28 m 46 m 112,8 m 250 m

27 Terrestrial lidar survey data visualization 3D view of the exit stairs

28 Terrestrial lidar survey path vectorialization

29 Terrestrial lidar survey path vectorialization ingresso uscita galleria artificiale

30 Terrestrial lidar survey path vectorialization Entrance path Exit path 101,1 m: from entrance to bottom of the turistic path 850 m: lenght of turistic path

31 Terrestrial lidar survey Giant Cave volume calculation

32 Terrestrial lidar survey data visualization Laser scan image, points coloured with photo. 38 m Traditional photography Colonna Ruggero

33 Terrestrial lidar survey data visualization Laser scan image Photography Laser scan image Photography

34 Terrestrial lidar survey data visualization

35 Terrestrial lidar survey data visualization

36 Terrestrial lidar survey data visualization

37 Terrestrial lidar survey to be continued 113,5 252,0?!?

38 Gravimetry Gravimetric measurements were carried out by means of a Lacoste&Romberg mod.d45microgravimeter. Approx. 200 stations were carried out. In order to calculate the Bougueranomalies at a density of 2.4 g/cm3, a topographic model derived from O.G.S.'s laser scan data was used.

39 Terrestrial lidar survey comparison Drawing by G. A. PERKO 1906

40 Terrestrial lidar survey comparison

41 Terrestrial lidar survey comparison

42 3D Laser Scan Technology Aerial and terrestrial laser survey in Grotta Gigante Thanks for watching