1v.lidar.growing(1) Grass User's Manual v.lidar.growing(1)
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6 v.lidar.growing - Building contour determination and Region Growing
7 algorithm for determining the building inside
8
10 vector, LIDAR
11
13 v.lidar.growing
14 v.lidar.growing help
15 v.lidar.growing input=name output=name first=name [tj=float]
16 [td=float] [--overwrite] [--verbose] [--quiet]
17 Flags:
19 --overwrite
20 Allow output files to overwrite existing files
21 --verbose
23 Verbose module output
24 --quiet
26 Quiet module output
27 Parameters:
29 input=name
30 Name of input vector map
31 output=name
33 Name for output vector map
34 first=name
36 Name of the first pulse vector map
37 tj=float
39 Threshold for cell object frequency in region growing
40 Default: 0.2
41 td=float
43 Threshold for double pulse in region growing
44 Default: 0.6
45
47 v.lidar.growing is the second of three steps to filter LiDAR data. The
48 filter aims to recognize and extract attached and detached object (such
49 as buildings, bridges, power lines, trees, etc.) in order to create a
50 Digital Terrain Model.
51 The modules identifies which is the internal area of every object on a
52 LiDAR point surface. The classification categories from v.lidar.edgede‐
53 tection are now rasterized. For each cell, it is evaluated if it (the
54 cell) contains a point with double impulse (difference between the
55 first and last pulse greater than a given threshold). Starting from
56 cells classified as OBJECT and with only one pulse all linked cells are
57 selected and a convex hull algorithm is applied to them. Simultane‐
58 ously, the mean of the corresponding heights (mean edge height) are
59 computed. Points inside the convex hull are classified as OBJECT if
60 their height is greater than or equal to the previously mean computed
61 edge height. This last step is done only in case of high planimetric
62 resolution.
63
65 The input data should be the output result of the v.lidar.correction
66 module. Otherwise, it goes to error! The output of this module will be
67 the input of v.lidar.correction module. The output will be a vector map
68 which points are pre-classified as:
69 TERRAIN SINGLE PULSE (cat = 1, layer = 2)
70 TERRAIN DOUBLE PULSE (cat = 2, layer = 2)
71 OBJECT SINGLE PULSE (cat = 3, layer = 2)
72 OBJECT DOUBLE PULSE (cat = 4, layer = 2)
73 The final result of the whole procedure (v.lidar.edgedetection,
74 v.lidar.growing, v.lidar.correction) will be a point classification in
75 the same categories as above.
76
78 Basic region growing procedure
79 v.lidar.growing input=edge output=growing
81
84 v.lidar.edgedetection, v.lidar.correction, v.surf.bspline
85
87 Original version of program in GRASS 5.4:
88 Maria Antonia Brovelli, Massimiliano Cannata, Ulisse Longoni and Mirko
89 Reguzzoni
90 Update for GRASS 6.X:
91 Roberto Antolin and Gonzalo Moreno
92
94 Antolin, R. et al., 2006. Digital terrain models determination by LiDAR
95 technology: Po basin experimentation. Bolletino di Geodesia e Scienze
96 Affini, anno LXV, n. 2, pp. 69-89.
97 Brovelli M. A., Cannata M., Longoni U.M., 2004. LIDAR Data Filtering
98 and DTM Interpolation Within GRASS, Transactions in GIS, April 2004,
99 vol. 8, iss. 2, pp. 155-174(20), Blackwell Publishing Ltd.
100 Brovelli M. A., Cannata M., 2004. Digital Terrain model reconstruction
101 in urban areas from airborne laser scanning data: the method and an
102 example for Pavia (Northern Italy). Computers and Geosciences 30 (2004)
103 pp.325-331
104 Brovelli M. A. and Longoni U.M., 2003. Software per il filtraggio di
105 dati LIDAR, Rivista dell?Agenzia del Territorio, n. 3-2003, pp. 11-22
106 (ISSN 1593-2192).
107 Brovelli M. A., Cannata M. and Longoni U.M., 2002. DTM LIDAR in area
108 urbana, Bollettino SIFET N.2, pp. 7-26.
109 Performances of the filter can be seen in the ISPRS WG III/3 Comparison
110 of Filters report by Sithole, G. and Vosselman, G., 2003.
111 Last changed: $Date: 2007-10-18 15:40:28 +0200 (Thu, 18 Oct 2007) $
113 Full index
115 © 2003-2008 GRASS Development Team
117GRASS 6.3.0 v.lidar.growing(1)