LASzip support in Pix4D, Gexcel R3 and ScanLook (LiDAR USA)
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Martin Isenburg
Aug 6, 2013, 1:51:36 PM8/6/13
to last...@googlegroups.com, christina...@pix4d.com
Hello,
i just got word that the LAZ format is now also supported by LiDAR USA's ScanLook as well as the Gexcel R3 software from Gexcel. I was not sure about Pix4D until I reveived a LAZ file that was apparently a "native" Pix4D export. So i did a quick Google search for "pix4d" and "laz" and the top hit was this page ... (-:
I am not sure whether there had actually been a plan to add LAZ support for 10.2, but with the LAStools.tbx LiDAR processing toolbox for ArcGIS 9.3, 10.0, 10.1, and 10.2 that is included with the default LAStools distribution we got you covered when you you need to read LAZ from within ESRI's flagship product ...
Martin @rapidlasso
--
http://rapidlasso.com - fast tools to zip your LiDARs
Martin Isenburg
Aug 7, 2013, 7:42:38 AM8/7/13
to last...@googlegroups.com, christina...@pix4d.com
Hello again,
just a curious observation for the LAZ files that were apparently produced directly by the Pix4D software. Running lasinfo.exe on one of the files (full report at the end of this message) I noticed four shortcomings.
(1) the bounding box is not populated
min x y z: 0.000 0.000 0.000
max x y z: 0.000 0.000 0.000
(2) a horrible offset value is used
offset x y z: 504439.05805969238 305222.88356018066 77.146867752075195
(3) a sub-optimal scaling factor is used (0.001 instead of 0.01) which will negatively affect compression but that is still a lot better than the insane scaling factors of 4.26875e-007 or similar that are used by the LAS exports of AgiSoft's PhotoScan ... (-:
scale factor x y z: 0.001 0.001 0.001
(4) a sub-optimal point type is used (3 instead of 2)
point data format: 3
now I am not sure if this was just the particular settings for this export or whether some other software has been importing and exporting the files in between. Could anyone else run lasinfo.exe on a LAZ file that is a direct export from Pix4D and share the result with me?
Thanks,
Martin @rapidlasso
---
D:\lastools\bin>lasinfo -i pointcloud_0.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: 1.2
system identifier: 'libLAS'
generating software: 'libLAS 1.7.0'
file creation day/year: 212/2013
header size: 227
offset to point data: 1159
number var. length records: 3
point data format: 3
point data record length: 34
number of point records: 9769243
number of points by return: 0 0 0 0 0
scale factor x y z: 0.001 0.001 0.001
offset x y z: 504439.05805969238 305222.88356018066 77.146867752075195
min x y z: 0.000 0.000 0.000
max x y z: 0.000 0.000 0.000
variable length header record 1 of 3:
reserved 43707
user ID 'LASF_Projection'
record ID 34735
length after header 64
description 'GeoTIFF GeoKeyDirectoryTag'
GeoKeyDirectoryTag version 1.1.0 number of keys 7
key 1024 tiff_tag_location 0 count 1 value_offset 1 - GTModelTypeGeoKey: ModelTypeProjected
key 1025 tiff_tag_location 0 count 1 value_offset 1 - GTRasterTypeGeoKey: RasterPixelIsArea
key 2054 tiff_tag_location 0 count 1 value_offset 9102 - GeogAngularUnitsGeoKey: Angular_Degree
key 3076 tiff_tag_location 0 count 1 value_offset 9001 - ProjLinearUnitsGeoKey: Linear_Meter
variable length header record 2 of 3:
reserved 43707
user ID 'LASF_Projection'
record ID 34737
length after header 44
description 'GeoTIFF GeoAsciiParamsTag'
GeoAsciiParamsTag (number of characters 44)
variable length header record 3 of 3:
reserved 43707
user ID 'liblas'
record ID 2112
length after header 662
description 'OGR variant of OpenGIS WKT SRS'
LASzip compression (version 2.1r0 c2 50000): POINT10 2 GPSTIME11 2 RGB12 2
reporting minimum and maximum for all LAS point record entries ...
X -402932 402932
Y -303860 303860
Z -13386 13386
intensity 0 0
edge_of_flight_line 0 0
scan_direction_flag 0 0
number_of_returns_of_given_pulse 0 0
return_number 0 0
classification 0 0
scan_angle_rank 0 0
user_data 0 0
point_source_ID 0 0
gps_time 0.000000 0.000000
Color R 3328 65280
G 5632 65280
B 5120 65280
WARNING: 9769243 points outside of header bounding box
WARNING: there are 9769243 points with return number 0
WARNING: there are 9769243 points with a number of returns of given pulse of 0
histogram of classification of points:
9769243 Created, never classified (0)
real max x larger than header max x by 504841.990060
real max y larger than header max y by 305526.743560
real max z larger than header max z by 90.532868
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René Giovanni Borella
Aug 14, 2013, 3:50:06 AM8/14/13
to last...@googlegroups.com, christina...@pix4d.com
I can second that. this file was generated by Postflight Terra (sensefly, with Pix4D innards)
lasinfo follows:
--
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: 1.2
system identifier: 'libLAS'
generating software: 'libLAS 1.7.0'
file creation day/year: 191/2013
header size: 227
offset to point data: 1138
number var. length records: 3
point data format: 3
point data record length: 34
number of point records: 18124857
number of points by return: 0 0 0 0 0
scale factor x y z: 0.001 0.001 0.001
offset x y z: 444933.36312000005 6206717.4976400007 11.100243926048279
min x y z: 0.000 0.000 0.000
max x y z: 0.000 0.000 0.000
variable length header record 1 of 3:
reserved 43707
user ID 'LASF_Projection'
record ID 34735
length after header 64
description 'GeoTIFF GeoKeyDirectoryTag'
GeoKeyDirectoryTag version 1.1.0 number of keys 7
key 1024 tiff_tag_location 0 count 1 value_offset 1 - GTModelTypeGeoKey: ModelTypeProjected
key 1025 tiff_tag_location 0 count 1 value_offset 1 - GTRasterTypeGeoKey: RasterPixelIsArea
key 1026 tiff_tag_location 34737 count 22 value_offset 0 - GTCitationGeoKey: ETRS89 / UTM zone 32N
key 2049 tiff_tag_location 34737 count 7 value_offset 22 - GeogCitationGeoKey: ETRS89
key 2054 tiff_tag_location 0 count 1 value_offset 9102 - GeogAngularUnitsGeoKey: Angular_Degree
key 3072 tiff_tag_location 0 count 1 value_offset 25832 - ProjectedCSTypeGeoKey: PCS_ETRS89_UTM_zone_32N
key 3076 tiff_tag_location 0 count 1 value_offset 9001 - ProjLinearUnitsGeoKey: Linear_Meter
variable length header record 2 of 3:
reserved 43707
user ID 'LASF_Projection'
record ID 34737
length after header 29
description 'GeoTIFF GeoAsciiParamsTag'
GeoAsciiParamsTag (number of characters 29)
ETRS89 / UTM zone 32N|ETRS89|
variable length header record 3 of 3:
reserved 43707
user ID 'liblas'
record ID 2112
length after header 656
description 'OGR variant of OpenGIS WKT SRS'
reporting minimum and maximum for all LAS point record entries ...
X -267528 267528
Y -284434 284434
Z -13744 13744
intensity 0 0
edge_of_flight_line 0 0
scan_direction_flag 0 0
number_of_returns_of_given_pulse 0 0
return_number 0 0
classification 0 0
scan_angle_rank 0 0
user_data 0 0
point_source_ID 0 0
gps_time 0.000000 0.000000
Color R 0 65280
G 0 65280
B 0 65280
WARNING: 18124857 points outside of header bounding box
WARNING: there are 18124857 points with return number 0
WARNING: there are 18124857 points with a number of returns of given pulse of 0
histogram of classification of points:
18124857 Created, never classified (0)
real max x larger than header max x by 445200.891120
real max y larger than header max y by 6207001.931640
real max z larger than header max z by 24.844244
real min z smaller than header min z by 2.643756
--
lasinfo end
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