1v.lidar.edgedetection(1) Grass User's Manual v.lidar.edgedetection(1)
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6 v.lidar.edgedetection - Detect the object's edges from a LIDAR data
7 set.
8
10 vector, LIDAR, edges
11
13 v.lidar.edgedetection
14 v.lidar.edgedetection help
15 v.lidar.edgedetection input=name output=name [see=float] [sen=float]
16 [lambda_g=float] [tgh=float] [tgl=float] [theta_g=float]
17 [lambda_r=float] [--overwrite]
18 Flags:
20 --overwrite
21 Parameters:
23 input=name
24 Name of input vector map
25 output=name
27 Name for output vector map
28 see=float
30 Interpolation spline step value in east direction Default: 4
31 sen=float
33 Interpolation spline step value in north direction Default: 4
34 lambda_g=float
36 Regularization weight in gradient evaluation Default: 0.01
37 tgh=float
39 High gradient threshold for edge classification Default: 6
40 tgl=float
42 Low gradient threshold for edge classification Default: 3
43 theta_g=float
45 Angle range for same direction detection Default: 0.26
46 lambda_r=float
48 Regularization weight in residual evaluation Default: 2
49
51 v.lidar.edgedetection is the first of three step to filter LIDAR data.
52 It detects the edge of each single feature over the terrain surface of
53 a LIDAR point surface. First of all, those points with a high gradient
54 value are determined. Then, it is valued the difference between the
55 observation of those points and a generic interpolated surface with
56 splines. If the difference is positive, then the point could supposed
57 to be inside the object, else the point could supposed to be outside
58 the object. The final output will be a vector map in which points has
59 been classified as TERRAIN, EDGE or UNKNOWN. This output will be the
60 input of v.lidar.growing module.
61
63 In this module, an external table will be created which will be useful
64 for the next module of the procedure of LIDAR data filtering. In this
65 table the interpolated height values of each point will be recorded.
66 The final result of the whole procedure (v.lidar.edgedetection,
67 v.lidar.growing, v.lidar.correction) will be a point classification in
68 four categories:
69 TERRAIN SINGLE PULSE
70 TERRAIN DOUBLE PULSE
71 OBJECT SINGLE PULSE
72 OBJECT DOUBLE PULSE
73
75 Basic edge detection
76 v.lidar.edgedetection input=vector_last output=edge see=8 sen=8
78 lambda_g=0.5
79
82 v.lidar.growing, v.lidar.correction
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85 Original version of program in GRASS 5.4:
86 Maria Antonia Brovelli, Massimiliano Cannata, Ulisse Longoni and Mirko
87 Reguzzoni
88 Update for GRASS 6.X:
89 Roberto Antolin and Gonzalo Moreno
90
92 Brovelli M. A.; Cannata M.; Longoni U.M., 2004, LIDAR Data Filtering
93 and DTM Interpolation Within GRASS, Transactions in GIS, April 2004,
94 vol. 8, iss. 2, pp. 155-174(20), Blackwell Publishing Ltd
95 Brovelli M. A., Cannata M., 2004, Digital Terrain model reconstruction
96 in urban areas from airborne laser scanning data: the method and an
97 example for Pavia (Northern Italy). Computers and Geosciences 30 (2004)
98 pp.325-331
99 Brovelli M. A. e Longoni U.M., 2003, Software per il filtraggio di
100 dati LIDAR, Rivista dell?Agenzia del Territorio, n. 3-2003, pp. 11-22
101 (ISSN 1593-2192)
102 Brovelli M. A., Cannata M. and Longoni U.M., 2002, DTM LIDAR in area
103 urbana, Bollettino SIFET N.2 ?2002, pp. 7- 26
104 Last changed: $Date: 2007/04/16 21:36:04 $
106 Full index
108GRASS 6.2.2 v.lidar.edgedetection(1)