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v.lidar.growing(1) Grass User's Manual v.lidar.growing(1)

v.lidar.growing - Building contour determination and Region Growing algorithm for determining the building inside

vector, LIDAR

v.lidar.growing
 
v.lidar.growing --help
 
v.lidar.growing input=name output=name first= name [tj=float] [td=float] [-- overwrite] [--help] [--verbose] [--quiet] [--ui]

--overwrite
 
Allow output files to overwrite existing files
--help
 
Print usage summary
--verbose
 
Verbose module output
--quiet
 
Quiet module output
--ui
 
Force launching GUI dialog

input=name [required]
 
Name of input vector map
 
Input vector (v.lidar.edgedetection output)
output=name [required]
 
Name for output vector map
first=name [required]
 
Name of the first pulse vector map
tj=float
 
Threshold for cell object frequency in region growing
 
Default: 0.2
td=float
 
Threshold for double pulse in region growing
 
Default: 0.6

v.lidar.growing is the second of three steps to filter LiDAR data. The filter aims to recognize and extract attached and detached object (such as buildings, bridges, power lines, trees, etc.) in order to create a Digital Terrain Model.
 
 
The modules identifies which is the internal area of every object on a LiDAR point surface. The classification categories from v.lidar.edgedetection are now rasterized. For each cell, it is evaluated if it (the cell) contains a point with double impulse (difference between the first and last pulse greater than a given threshold). Starting from cells classified as OBJECT and with only one pulse all linked cells are selected and a convex hull algorithm is applied to them. Simultaneously, the mean of the corresponding heights (mean edge height) are computed. Points inside the convex hull are classified as OBJECT if their height is greater than or equal to the previously mean computed edge height. This last step is done only in case of high planimetric resolution.

The input data should be the output result of the v.lidar.edgedetection, module. Otherwise, it goes to error! The output of this module will be the input of v.lidar.correction module. The output will be a vector map which points are pre-classified as:
 
 
TERRAIN SINGLE PULSE (cat = 1, layer = 2)
 
TERRAIN DOUBLE PULSE (cat = 2, layer = 2)
 
OBJECT SINGLE PULSE (cat = 3, layer = 2)
 
OBJECT DOUBLE PULSE (cat = 4, layer = 2)
 
 
The final result of the whole procedure ( v.lidar.edgedetection, v.lidar.growing, v.lidar.correction) will be a point classification in the same categories as above.

v.lidar.growing input=edge output=growing first=firstpulse

v.lidar.edgedetection, v.lidar.correction, v.surf.bspline, v.surf.rst, v.in.lidar, v.in.ascii

Original version of program in GRASS 5.4:
 
Maria Antonia Brovelli, Massimiliano Cannata, Ulisse Longoni and Mirko Reguzzoni
Update for GRASS 6.X:
 
Roberto Antolin and Gonzalo Moreno

Antolin, R. et al., 2006. Digital terrain models determination by LiDAR technology: Po basin experimentation. Bolletino di Geodesia e Scienze Affini, anno LXV, n. 2, pp. 69-89.
Brovelli M. A., Cannata M., Longoni U.M., 2004. LIDAR Data Filtering and DTM Interpolation Within GRASS, Transactions in GIS, April 2004, vol. 8, iss. 2, pp. 155-174(20), Blackwell Publishing Ltd.
Brovelli M. A., Cannata M., 2004. Digital Terrain model reconstruction in urban areas from airborne laser scanning data: the method and an example for Pavia (Northern Italy). Computers and Geosciences 30 (2004) pp.325-331
Brovelli M. A. and Longoni U.M., 2003. Software per il filtraggio di dati LIDAR, Rivista dell?Agenzia del Territorio, n. 3-2003, pp. 11-22 (ISSN 1593-2192).
Brovelli M. A., Cannata M. and Longoni U.M., 2002. DTM LIDAR in area urbana, Bollettino SIFET N.2, pp. 7-26.
Performances of the filter can be seen in the ISPRS WG III/3 Comparison of Filters report by Sithole, G. and Vosselman, G., 2003.
 
Last changed: $Date: 2015-09-08 04:45:01 +0200 (Tue, 08 Sep 2015) $

Available at: v.lidar.growing source code (history)
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© 2003-2018 GRASS Development Team, GRASS GIS 7.4.3 Reference Manual
GRASS 7.4.3

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