deleting RGB information from LAS/LAZ files
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Martin Isenburg
Dec 3, 2016, 10:19:26 AM12/3/16
to LAStools - efficient command line tools for LIDAR processing
Hello,
I was asked how to remove RGB information from a LAS / LAZ file. Here a little example. Let's first create an colored RGB point cloud:
lasgrid -i ..\data\fusa.laz ^
-keep_class 5 6 ^
-classification -false ^
-o fusa_stuff.tif
lascolor -i ..\data\fusa.laz ^
-image fusa_stuff.tif ^
-o fusa_col.laz
Now the 'fusa_col.laz' has point type 3 and store an RGB color for each point. We can remove these color again either by setting it to zero as shown below. But then then point type remains unchanged and the file still stores 6 zero bytes per point (that get compressed away to near-nothing by LASzip when files are stored as LAZ).
las2las -i fusa_col.laz ^
-set_RGB 0 0 0 ^
-o fusa_col_zeroed.laz
Or we can set the point type to 1 as shown below which removed the colors because there is no space for them to be stored. The three corresponding lasinfo reports are shown at the end.
las2las -i fusa_col.laz ^
-set_point_type 1 ^
-o fusa_col_removed.laz
Regards,
Martin @rapidlasso
=========================================
E:\LAStools\bin>lasinfo fusa_col.laz
lasinfo (161114) report for fusa_col.laz
reporting all LAS header entries:
file signature: 'LASF'
file source ID: 0
global_encoding: 0
project ID GUID data 1-4: 00000000-0000-0000-0000-000000000000
version major.minor: 1.1
system identifier: 'LAStools (c) by rapidlasso GmbH'
generating software: 'lascolor (161114) academic'
file creation day/year: 40/2010
header size: 227
offset to point data: 321
number var. length records: 1
point data format: 3
point data record length: 34
number of point records: 277573
number of points by return: 263413 13879 281 0 0
scale factor x y z: 0.01 0.01 0.01
offset x y z: 0 0 0
min x y z: 277750.00 6122250.00 42.21
max x y z: 277999.99 6122499.99 64.35
variable length header record 1 of 1:
reserved 43707
user ID 'LASF_Projection'
record ID 34735
length after header 40
description 'by LAStools of Martin Isenburg'
GeoKeyDirectoryTag version 1.1.0 number of keys 4
key 1024 tiff_tag_location 0 count 1 value_offset 1 - GTModelTypeGeoKey: ModelTypeProjected
key 3072 tiff_tag_location 0 count 1 value_offset 32754 - ProjectedCSTypeGeoKey: WGS 84 / UTM 54S
key 3076 tiff_tag_location 0 count 1 value_offset 9001 - ProjLinearUnitsGeoKey: Linear_Meter
key 4099 tiff_tag_location 0 count 1 value_offset 9001 - VerticalUnitsGeoKey: Linear_Meter
LASzip compression (version 2.4r1 c2 50000): POINT10 2 GPSTIME11 2 RGB12 2
reporting minimum and maximum for all LAS point record entries ...
X 27775000 27799999
Y 612225000 612249999
Z 4221 6435
intensity 10 62293
return_number 1 3
number_of_returns 1 3
edge_of_flight_line 0 0
scan_direction_flag 0 0
classification 1 6
scan_angle_rank 79 103
user_data 0 197
point_source_ID 1 1
gps_time 5880.963028 5886.739738
Color R 0 65280
G 0 65280
B 0 19712
number of first returns: 263413
number of intermediate returns: 283
number of last returns: 263370
number of single returns: 249493
overview over number of returns of given pulse: 249493 27232 848 0 0 0 0
histogram of classification of points:
17553 unclassified (1)
180868 ground (2)
37030 high vegetation (5)
42122 building (6)
=========================================
E:\LAStools\bin>lasinfo fusa_col_zeroed.laz
lasinfo (161114) report for fusa_col_zeroed.laz
reporting all LAS header entries:
file signature: 'LASF'
file source ID: 0
global_encoding: 0
project ID GUID data 1-4: 00000000-0000-0000-0000-000000000000
version major.minor: 1.1
system identifier: 'LAStools (c) by rapidlasso GmbH'
generating software: 'las2las (version 161128)'
file creation day/year: 40/2010
header size: 227
offset to point data: 321
number var. length records: 1
point data format: 3
point data record length: 34
number of point records: 277573
number of points by return: 263413 13879 281 0 0
scale factor x y z: 0.01 0.01 0.01
offset x y z: 0 0 0
min x y z: 277750.00 6122250.00 42.21
max x y z: 277999.99 6122499.99 64.35
variable length header record 1 of 1:
reserved 43707
user ID 'LASF_Projection'
record ID 34735
length after header 40
description 'by LAStools of Martin Isenburg'
GeoKeyDirectoryTag version 1.1.0 number of keys 4
key 1024 tiff_tag_location 0 count 1 value_offset 1 - GTModelTypeGeoKey: ModelTypeProjected
key 3072 tiff_tag_location 0 count 1 value_offset 32754 - ProjectedCSTypeGeoKey: WGS 84 / UTM 54S
key 3076 tiff_tag_location 0 count 1 value_offset 9001 - ProjLinearUnitsGeoKey: Linear_Meter
key 4099 tiff_tag_location 0 count 1 value_offset 9001 - VerticalUnitsGeoKey: Linear_Meter
LASzip compression (version 2.4r1 c2 50000): POINT10 2 GPSTIME11 2 RGB12 2
reporting minimum and maximum for all LAS point record entries ...
X 27775000 27799999
Y 612225000 612249999
Z 4221 6435
intensity 10 62293
return_number 1 3
number_of_returns 1 3
edge_of_flight_line 0 0
scan_direction_flag 0 0
classification 1 6
scan_angle_rank 79 103
user_data 0 197
point_source_ID 1 1
gps_time 5880.963028 5886.739738
Color R 0 0
G 0 0
B 0 0
number of first returns: 263413
number of intermediate returns: 283
number of last returns: 263370
number of single returns: 249493
overview over number of returns of given pulse: 249493 27232 848 0 0 0 0
histogram of classification of points:
17553 unclassified (1)
180868 ground (2)
37030 high vegetation (5)
42122 building (6)
=========================================
E:\LAStools\bin>lasinfo fusa_col_removed.laz
lasinfo (161114) report for fusa_col_removed.laz
reporting all LAS header entries:
file signature: 'LASF'
file source ID: 0
global_encoding: 0
project ID GUID data 1-4: 00000000-0000-0000-0000-000000000000
version major.minor: 1.1
system identifier: 'LAStools (c) by rapidlasso GmbH'
generating software: 'las2las (version 161128)'
file creation day/year: 40/2010
header size: 227
offset to point data: 321
number var. length records: 1
point data format: 1
point data record length: 28
number of point records: 277573
number of points by return: 263413 13879 281 0 0
scale factor x y z: 0.01 0.01 0.01
offset x y z: 0 0 0
min x y z: 277750.00 6122250.00 42.21
max x y z: 277999.99 6122499.99 64.35
variable length header record 1 of 1:
reserved 43707
user ID 'LASF_Projection'
record ID 34735
length after header 40
description 'by LAStools of Martin Isenburg'
GeoKeyDirectoryTag version 1.1.0 number of keys 4
key 1024 tiff_tag_location 0 count 1 value_offset 1 - GTModelTypeGeoKey: ModelTypeProjected
key 3072 tiff_tag_location 0 count 1 value_offset 32754 - ProjectedCSTypeGeoKey: WGS 84 / UTM 54S
key 3076 tiff_tag_location 0 count 1 value_offset 9001 - ProjLinearUnitsGeoKey: Linear_Meter
key 4099 tiff_tag_location 0 count 1 value_offset 9001 - VerticalUnitsGeoKey: Linear_Meter
LASzip compression (version 2.4r1 c2 50000): POINT10 2 GPSTIME11 2
reporting minimum and maximum for all LAS point record entries ...
X 27775000 27799999
Y 612225000 612249999
Z 4221 6435
intensity 10 62293
return_number 1 3
number_of_returns 1 3
edge_of_flight_line 0 0
scan_direction_flag 0 0
classification 1 6
scan_angle_rank 79 103
user_data 0 197
point_source_ID 1 1
gps_time 5880.963028 5886.739738
number of first returns: 263413
number of intermediate returns: 283
number of last returns: 263370
number of single returns: 249493
overview over number of returns of given pulse: 249493 27232 848 0 0 0 0
histogram of classification of points:
17553 unclassified (1)
180868 ground (2)
37030 high vegetation (5)
42122 building (6)
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