Changes between Version 5 and Version 6 of Processing/Splitting


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Timestamp:
Nov 19, 2014 4:35:37 PM (5 years ago)
Author:
tec
Comment:

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  • Processing/Splitting

    v5 v6  
    118118
    119119{{{
    120 split_las.py (-d INPUTDIR | -f INPUTFILE) [-o OVERLAP] outputdir fraction
     120split_las.py (-d INPUTDIR | -i INPUTFILE | -l INPUTLIST... ) -o OUTPUTDIR (--time time | --speed SPEED --distance DISTANCE )
    121121}}}
    122122
    123 This can be run on either a single file or a directory of las files.
     123'''This is still slightly experimental (more so for FW) so inspect output files thoroughly'''
     124This can be run on either a single file, a space separated list or a directory of las files. You can specify the number of seconds for overlap using `--time` (default is 1s aka 65ish metres), you can also specify the overlap in metres if you specify the plane speed too. If you dont want overlap use `--time 0`. This script will split __full waveform__ and discrete LAS files.
    124125
    125 Use -o to specify the number of seconds of overlap, this can be used with the airplanes ground speed to calculate overlap. For instance 7 seconds 140 knots will result in an overlap of 504 metres (7 seconds * 72 m/s). Give the script a fraction for the number of lines to divide the line into, I usually just give it 3.
     126`lassplit` Is a C++ program which will split LAS files based on a GPS time range.
     127{{{
     128lassplit -l las_input_file -o las_output_file -s gps_start_time -e gps_end_time
     129}}}
    126130
    127131=== Full Waveform ===
    128132
    129 Full wave form data cannot use the script above. Unfortunately you will need to produce this using alspp and its fence feature.
     133Left this in as it is still useful.
    130134
    131135It is worthwhile using the script above to divide a discrete line then using the x/y coordinates from each section for your division. This will give you a consistent split across the waveform data. If you have variable pitch/roll you will likely have to process each line seperately.