v.lidar.correction(1)

1v.lidar.correction(1)         Grass User's Manual        v.lidar.correction(1)
2
3
4

NAME

6       v.lidar.correction   -  Correction of the v.lidar.growing output. It is
7       the last of the three algorithms for LIDAR filtering
8

KEYWORDS

10       vector, LIDAR
11

SYNOPSIS

13       v.lidar.correction
14       v.lidar.correction help
15       v.lidar.correction  input=name  output=name  out_terrain=name    [data‐
16       base=string]         [driver=string]        [sce=float]       scn=float
17       [lambda_c=float]   [tch=float]   [tcl=float]   [--overwrite]
18
19   Flags:
20       --overwrite
21
22   Parameters:
23       input=name
24           Input observation vector map name (v.lidar.growing output)
25
26       output=name
27           Output classified vector map name
28
29       out_terrain=name
30           Output terrain only vector map name
31
32       database=string
33           Database name
34
35       driver=string
36           Driver name Options: dbf,mysql,ogr,pg,sqlite,mesql,odbc
37
38       sce=float
39           Interpolation spline step value in east direction Default: 25
40
41       scn=float
42           Interpolation spline step value in north direction Default: 25
43
44       lambda_c=float
45           Regularization weight in reclassification evaluation Default: 1
46
47       tch=float
48           High threshold for object to terrain reclassification Default: 2
49
50       tcl=float
51           Low threshold for terrain to object reclassification Default: 1
52

DESCRIPTION

54       v.lidar.correction is the last of three step to filter LIDAR  data.  It
55       makes  a  comparison between the LIDAR observations and an interpolated
56       surface in which only terrain points have been used. Once the new  ref‐
57       erence surface is obtained, a point reclassification is done:
58       a)  Points  classified as TERRAIN differing more than a threshold value
59       are interpreted and reclassified as OBJECT.
60       b) Points classified as OBJECT and closed enough  to  the  interpolated
61       surface are interpreted and reclassified as TERRAIN.
62       The  input should be the output of v.lidar.growing module or the output
63       of this v.lidar.correction itself. That means,  this  module  could  be
64       applied more times (although, two are enough) for a better filter solu‐
65       tion. The outputs are a vector map with a final point classification as
66       as  TERRAIN  SINGLE PULSE, TERRAIN DOUBLE PULSE, OBJECT SINGLE PULSE or
67       OBJECT DOUBLE PULSE; and an vector map with only the points  classified
68       as TERRAIN SINGLE PULSE or TERRAIN DOUBLE PULSE.
69

NOTES

71       The   final  result  of  the  whole  procedure  (v.lidar.edgedetection,
72       v.lidar.growing, v.lidar.correction) will be a point classification  in
73       four categories:
74       TERRAIN SINGLE PULSE
75       TERRAIN DOUBLE PULSE
76       OBJECT SINGLE PULSE
77       OBJECT DOUBLE PULSE
78

EXAMPLES

80   Basic correction procedure
81
82       v.lidar.correction     input=growing     output=correction     out_ter‐
83       rain=only_terrain
84
85
86   Second correction procedure
87
88       v.lidar.correction  input=correction   output=correction_bis   out_ter‐
89       rain=only_terrain_bis
90
91

AUTHORS

96       Original version of program in GRASS 5.4:
97       Maria  Antonia Brovelli, Massimiliano Cannata, Ulisse Longoni and Mirko
98       Reguzzoni
99       Update for GRASS 6.X:
100       Roberto Antolin and Gonzalo Moreno
101

REFERENCES

103       Brovelli M. A., Cannata M., and Longoni U.M., 2004, LIDAR Data  Filter‐
104       ing  and  DTM  Interpolation  Within  GRASS, Transactions in GIS, April
105       2004, vol. 8, iss. 2, pp. 155-174(20), Blackwell Publishing Ltd
106       Brovelli M. A. and Cannata M., 2004, Digital Terrain model  reconstruc‐
107       tion   in urban areas from airborne laser scanning data: the method and
108       an  example for Pavia (Northern Italy). Computers and  Geosciences  30,
109       pp.325-331
110       Brovelli  M. A e Longoni U.M., 2003, Software per il filtraggio di dati
111       LIDAR, Rivista dell'Agenzia del Territorio, n. 3-2003, pp. 11-22  (ISSN
112       1593-2192)
113       Brovelli  M.  A., Cannata M. and Longoni U.M., 2002, DTM LIDAR in  area
114       urbana, Bollettino SIFET N.2, 2002, pp. 7-26
115
116       Last changed: $Date: 2007/04/16 21:36:04 $
117
118       Full index
119
120
121
122GRASS 6.2.2                                              v.lidar.correction(1)