NAME

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

KEYWORDS

       vector, LIDAR

SYNOPSIS

       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]

   Flags:
       --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

   Parameters:
       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

DESCRIPTION

       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.

NOTES

       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.

EXAMPLES

   Basic region growing procedure
       v.lidar.growing input=edge output=growing first=firstpulse

SEE ALSO

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

AUTHOR

       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

REFERENCES

       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.

SOURCE CODE

       Available at: v.lidar.growing source code (history)

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       © 2003-2019 GRASS Development Team, GRASS GIS 7.8.2 Reference Manual