Changes between Version 5 and Version 6 of Processing/LidarNoisyPoints


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Timestamp:
Feb 13, 2015 2:20:36 PM (4 years ago)
Author:
dac
Comment:

Updated las2las text

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  • Processing/LidarNoisyPoints

    v5 v6  
    11= Post Processing LiDAR Point Clouds=
    22
    3 The usual form of delivery of the processed LiDAR data is in the form of a point cloud. This takes one of two forms; [http://arsf-dan.nerc.ac.uk/trac/wiki/FAQ/lidarasciiformat ASCII text files] or binary [http://www.asprs.org/Committee-General/LASer-LAS-File-Format-Exchange-Activities.html LAS] files. The point clouds contain all the LiDAR data as vectors, a list of individual points, rather than as rasterised data.
     3The usual form of delivery of the processed LiDAR data is in the form of a point cloud. This takes one of two forms; [http://arsf-dan.nerc.ac.uk/trac/wiki/FAQ/lidarasciiformat ASCII text files] or binary [http://www.asprs.org/Committee-General/LASer-LAS-File-Format-Exchange-Activities.html LAS] files. The files contain the coordinates of each detected LiDAR return, from these a raster DEM can be created.
    44
    55== Removing Noise Points ==
     
    3131pt_cloud_filter.exe point_cloud.txt 7 > filtered_point_cloud.txt
    3232}}}
    33 
    3433will create a file called filtered_point_cloud.txt from the points in point_cloud.txt excluding those with classification 7.
    3534
     
    3736=== Removing noisy points from LAS files ===
    3837
    39 To remove them from LAS files it is suggested to download the [http://www.cs.unc.edu/~isenburg/lastools/ LASTools] package, specifically the [http://www.cs.unc.edu/~isenburg/lastools/download/las2las_README.txt las2las] tool.
     38To remove them from LAS files it is suggested to download the [https://github.com/LAStools/LAStools LASTools] package, specifically the open source [http://www.cs.unc.edu/~isenburg/lastools/download/las2las_README.txt las2las] tool.
    4039
    41 This can be used to remove noise points by typing:
     40The following command can be used to create a copy of the LAS file, removing points flagged as noise:
    4241
    4342{{{
    44 las2las -i point_cloud.txt -o filtered_point_cloud.txt -drop_class 7
     43las2las -i point_cloud.las -o filtered_point_cloud.las -drop_class 7
    4544}}}
    4645
    47 which will create a new file called filtered_point_cloud.txt from the points in point_cloud.txt excluding those with classification 7.