pelatihan : techniques in active tectonic study juni 20-juli 2, 2013
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Pelatihan : Techniques in Active Tectonic Study Juni 20-Juli 2, 2013 Instruktur: Prof. J Ramon Arrowsmith (JRA) Dari Arizona State University (ASU) - US. Tempat Pelaksanaan: - PowerPoint PPT PresentationTRANSCRIPT
Pelatihan :
Techniques in Active Tectonic StudyJuni 20-Juli 2, 2013
Instruktur: Prof. J Ramon Arrowsmith (JRA)Dari Arizona State University (ASU) - US
Tempat Pelaksanaan: Ruang Pangea, Laboratorium Gempabumi (LabEarth) –
Puslit Geoteknologi LIPI dan Kuliah lapangan akan dilakukan disekitar Sesar Lembang, Jawa Barat.
* Lebih jelas baca TOR/KAK dan daftar acara
High resolution topography exercise and discussion
Airborne Laser Swath Mapping (ALSM)
1 5 - 2 0 c m
D irec tio n o f
F lig h t
G P S R e fe re n c eB a se S ta tio n
Laser
L ase r P u lseL ase r
S p o t S ize
S can L in e
1. Laser scanner
2. Inertial Measureme
nt Unit (IMU)
3. GPS
-Phillips, UNAVCO
R. Haugerud, U.S.G.S
D. Harding, NASA
Answer science question
Gridded productsGeodesy and signal processing
Point Cloudxn, yn, zn, in
ALSM workflow:
Survey->Process->Classify->Interpolate/Grid->Analyze
Ecology Applications:
• 3D vegetation information & interactions between vegetation and topography
• 3D vegetation structure:
– estimation of stand height
– total aboveground biomass
– foliage biomass
– basal area
– tree density,
– canopy base height
– canopy bulk density
Stoker et al., 2006
Comparisons of Techniques for measuring surfaces and detecting changes in surfaces*
GPS InSAR ALSM TLSSample
Density
1 site/10 km2 10,000 pixels/ km2
1-10 hits/ m2 1000 hits/ m2
Position
Precision
1-20 mm 2-3 m 5-15 cm 0.6-5 cm
Change
Detection
1 mm 1-2 cm 10 cm 1 cm
Scale Global 100 km 10-100 Km 1 km
* Ball park numbers for typical applications
-Phillips, Meertens, and Jackson, UNAVCO
• x,y,z + attributes
• Filtering algorithms allow classification by return type:– Ground, vegetation, building …
LiDAR “point cloud”
Digital Elevation Models• Digital representation of
topography / terrain– “Raster” format – a grid of
squares or “pixels”– Continuous surface where Z
(elevation) is estimated on a regular X,Y grid
– “2.5D”
• Grid resolution is defined by the size in the horizontal dimension of the pixel– 1 meter DEM has pixels 1 m x 1m assigned a single
elevation value.
Source: http://www.ncgia.ucsb.edu/giscc/extra/e001/e001.html
• 1 meter grid
• LiDAR returns from EarthScope data collection
• Example from flat area with little or no vegetation so ground is sampled approx. 5+ times per square meter
• How do we best fit a continuous surface to these points?
• Ultimately wish to represent irregularly sampled data on a regularized grid.
1 meter1
met
er
Facilitate community access to high-resolution, Earth science-oriented, topography data, and related tools and resources.
http://www.opentopography.org
Let’s tour OpenTopography
http://rapidlasso.com/