1v.in.lidar(1) Grass User's Manual v.in.lidar(1)
2
6 v.in.lidar - Converts LAS LiDAR point clouds to a GRASS vector map
7 with libLAS.
8
10 vector, import, LIDAR, level1
11
13 v.in.lidar
14 v.in.lidar --help
15 v.in.lidar [-pruvetcboi] input=name output=name [id_layer=string]
16 [return_layer=string] [class_layer=string] [rgb_layer=string]
17 [spatial=xmin,ymin,xmax,ymax[,xmin,ymin,xmax,ymax,...]]
18 [zrange=min,max] [return_filter=string] [class_filter=inte‐
19 ger[,integer,...]] [mask=name] [mask_layer=string] [skip=integer]
20 [preserve=integer] [offset=integer] [limit=integer] [loca‐
21 tion=name] [--overwrite] [--help] [--verbose] [--quiet] [--ui]
22 Flags:
24 -p
25 Print LAS file info and exit
26 -r
28 Limit import to the current region
29 -u
31 Invert mask when selecting points
32 -v
34 Use only valid points
35 Points invalid according to APSRS LAS specification will be fil‐
36 tered out
37 -e
39 Extend region extents based on new dataset
40 -t
42 Do not create attribute table
43 -c
45 Do not automatically add unique ID as category to each point
46 Create only requested layers and categories
47 -b
49 Do not build topology
50 Advantageous when handling a large number of points
51 -o
53 Override projection check (use current location’s projection)
54 Assume that the dataset has same projection as the current location
55 -i
57 Create the location specified by the "location" parameter and exit.
58 Do not import the vector data.
59 --overwrite
61 Allow output files to overwrite existing files
62 --help
64 Print usage summary
65 --verbose
67 Verbose module output
68 --quiet
70 Quiet module output
71 --ui
73 Force launching GUI dialog
74 Parameters:
76 input=name [required]
77 LAS input file
78 LiDAR input files in LAS format (*.las or *.laz)
79 output=name [required]
81 Name for output vector map
82 id_layer=string
84 Layer number to store generated point ID as category
85 Set to 1 by default, use -c to not store it
86 return_layer=string
88 Layer number to store return information as category
89 Leave empty to not store it
90 class_layer=string
92 Layer number to store class number as category
93 Leave empty to not store it
94 rgb_layer=string
96 Layer number where RBG colors are stored as category
97 Leave empty to not store it
98 spatial=xmin,ymin,xmax,ymax[,xmin,ymin,xmax,ymax,...]
100 Import subregion only
101 Format: xmin,ymin,xmax,ymax - usually W,S,E,N
102 zrange=min,max
104 Filter range for z data (min,max)
105 return_filter=string
107 Only import points of selected return type
108 If not specified, all points are imported
109 Options: first, last, mid
110 class_filter=integer[,integer,...]
112 Only import points of selected class(es)
113 Input is comma separated integers. If not specified, all points are
114 imported.
115 mask=name
117 Areas where to import points
118 Name of vector map with areas where the points should be imported
119 mask_layer=string
121 Layer number or name for mask option
122 Vector features can have category values in different layers. This
123 number determines which layer to use. When used with direct OGR
124 access this is the layer name.
125 Default: 1
126 skip=integer
128 Do not import every n-th point
129 For example, 5 will import 80 percent of points. If not specified,
130 all points are imported
131 preserve=integer
133 Import only every n-th point
134 For example, 4 will import 25 percent of points. If not specified,
135 all points are imported
136 offset=integer
138 Skip first n points
139 Skips the given number of points at the beginning.
140 limit=integer
142 Import only n points
143 Imports only the given number of points
144 location=name
146 Name for new location to create
147
149 v.in.lidar converts LiDAR point clouds in LAS format to a GRASS vector,
150 using the libLAS library. The created vector is true 3D with x, y, z
151 coordinates.
152 For larger datasets, it is recommended to not build topology (-b flag).
154 Also, creating a table with attributes can take some time for larger
155 datasets.
156 The optional spatial parameter defines spatial query extents. This
158 parameter allows the user to restrict the region to a spatial subset
159 while importing the data. All LiDAR points falling into this rectangle
160 subregion are imported. The -r current region flag is identical, but
161 uses the current region settings as the spatial bounds (see g.region).
162 A LiDAR pulse can have multiple returns. The first return values can be
164 used to obtain a digital surface model (DSM) where e.g. canopy cover is
165 represented. The last return values can be used to obtain a digital
166 terrain model (DTM) where e.g. the forest floor instead of canopy cover
167 is represented. The return_filter option allows selecting one of first,
168 mid, or last returns.
169 LiDAR points can be already classified into standardized classes. For
171 example, class number 2 represents ground (for other classes see LAS
172 format specification in references). The class_filter option allows
173 selecting one or more classes, as numbers (integers) separated by
174 comma.
175 Note that proper filtering of the input points in not only critical for
177 the analysis itself but it can also speed up the processing signifi‐
178 cantly.
179 Decimation
181 Table with selected percentages of points to keep with corresponding
182 decimation parameters:
183 percentage parameters
185 0.1% preserve=1000
187 1% preserve=100
189 5% preserve=20
191 10% preserve=10
193 20% preserve=5
195 25% preserve=4
197 50% skip=2
199 75% skip=4
201 80% skip=5
203 90% skip=10
207 Table with selected fractions of points to keep with corresponding dec‐
209 imation parameters:
210 ratio parameters
212 1/3 preserve=3
214 1/4 preserve=4
216 1/5 preserve=5
218 1/6 preserve=6
220 Table with selected fractions of points to throw away with correspond‐
222 ing decimation parameters:
223 ratio parameters
225 1/3 skip=3
227 1/4 skip=4
229 1/5 skip=5
231 1/6 skip=6
233
236 v.in.lidar attempts to preserve projection information when importing
237 datasets if the source format includes projection information, and if
238 the LAS driver supports it. If the projection of the source dataset
239 does not match the projection of the current location v.in.lidar will
240 report an error message ("Projection of dataset does not appear to
241 match current location") and then report the PROJ_INFO parameters of
242 the source dataset.
243 If the user wishes to ignore the difference between the apparent coor‐
245 dinate system of the source data and the current location, they may
246 pass the -o flag to override the projection check.
247 If the user wishes to import the data with the full projection defini‐
249 tion, it is possible to have v.in.lidar automatically create a new
250 location based on the projection and extents of the file being read.
251 This is accomplished by passing the name to be used for the new loca‐
252 tion via the location parameter. Upon completion of the command, a new
253 location will have been created (with only a PERMANENT mapset), and the
254 vector map will have been imported with the indicated output name into
255 the PERMANENT mapset.
256
258 The typical file extensions for the LAS format are .las and .laz (com‐
259 pressed). The compressed LAS (.laz) format can be imported only if
260 libLAS has been compiled with laszip support. It is also recommended to
261 compile libLAS with GDAL, needed to test for matching projections.
262
264 This example is analogous to the example used in the GRASS wiki page
265 for importing LAS as vector points.
266 The sample LAS data are in the file "Serpent Mound Model LAS Data.las",
268 available at appliedimagery.com
269 # print LAS file info
270 v.in.lidar -p input="Serpent Mound Model LAS Data.las"
271 # create location with projection information of the LAS data
272 v.in.lidar -i input="Serpent Mound Model LAS Data.las" location=Serpent_Mound
273 # quit and restart GRASS in the newly created location "Serpent_Mound"
274 # real import of LiDAR LAS data, without topology and without attribute table
275 v.in.lidar -tb input="Serpent Mound Model LAS Data.las" output=Serpent_Mound_Model_pts
276
278 r.in.lidar, r3.in.lidar, g.region, v.vect.stats, v.in.ogr
279
281 ASPRS LAS format
282 LAS library
283 LAS library C API documentation
284
286 Markus Metz
287 Vaclav Petras, NCSU GeoForAll Lab (decimation, cats, areas, zrange)
288 based on v.in.ogr by various authors
289 Last changed: $Date: 2016-08-23 04:00:20 +0200 (Tue, 23 Aug 2016) $
291
293 Available at: v.in.lidar source code (history)
294 Main index | Vector index | Topics index | Keywords index | Graphical
296 index | Full index
297 © 2003-2019 GRASS Development Team, GRASS GIS 7.6.0 Reference Manual
299GRASS 7.6.0 v.in.lidar(1)