Will lascopy transfer point flags with classification?

[Ryan Comeaux]

Is it possible to copy 'withheld' and 'keypoint' flags along with the classification in lascopy?

[Ken Comeaux]

Martin or whoever else might know is there an answer to Chase’s question?

  

  

On Tue, Jun 9, 2020 at 12:22 PM Ryan Comeaux <ryan.co...@gmail.com> wrote:

Is it possible to copy 'withheld' and 'keypoint' flags along with the classification in lascopy?

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Ken Comeaux CP

[Matthew Taylor]

Filter points based on classifications or flags.

  -keep_class 1 3 7

  -drop_class 4 2

  -keep_extended_class 43

  -drop_extended_class 129 135

  -drop_synthetic -keep_synthetic

  -drop_keypoint -keep_keypoint

  -drop_withheld -keep_withheld

  -drop_overlap -keep_overlap

 

 

Matthew Taylor R&D Manager 256.513.8521

 

 

www.atlantic.tech | t 256.971.9991 2223 Drake Avenue SW, Suite 200, Huntsville, AL 35805

 

 

 

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[Chase Comeaux]

Here are my results without and then with those commands:

 

lascopy -i %source%\%%G -i %target%\%%G -o %target%\%%G -odix _updated -classification

 

result:   copied 1926491 point attributes. total time 1.577 sec.

 

 

 

lascopy -i %source%\%%G -i %target%\%%G -o %target%\%%G -odix _updated -classification -keep_withheld -keep_keypoint

 

or

 

lascopy -i %source%\%%G -i %target%\%%G -o %target%\%%G -odix _updated -keep_withheld -keep_keypoint

 

result:                   copied 0 point attributes. total time 0.687 sec.

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[Michael Perdue]

Hi Chase,

AFAIK, there is no direct route to move the flags using lascopy at this time. However, there is an indirect route. You can convert the flags into classifications in an intermediate file, move the flags to the target file as classifications, update the flags in the target and then move the classification. It makes use of filtered transforms and is a little tedious, but is easy to script and can be run on multiple cores if set up properly.

:: Given a source file

lasinfo -i source.laz

...

histogram of classification of points:

         6441146  ground (2)

         4447709  medium vegetation (4)

 +-> flagged as keypoints: 1081631

  +--->         1081631 of those are ground (2)

 +-> flagged as withheld:  34

  +--->              34 of those are medium vegetation (4)

 

:: And a target file

lasinfo -i target.laz

...

histogram of classification of points:

        10888855  never classified (0)

 

 

::---------------------------------------------------------------------------

:: Step 1: Convert flags to classes

::---------------------------------------------------------------------------

:: Create copy of source.laz with all classes zero'd

las2las -set_classification 0 ^

        -i source.laz ^

        -o tmp.laz

 

:: Use a filtered transform to set withheld point to class 1

las2las -keep_withheld ^

        -filtered_transform ^

        -set_classification 1 ^

        -i tmp.laz ^

        -o tmp2.laz

 

:: Use a second filtered transform to set keypoints to class 2

las2las -keep_keypoint ^

        -filtered_transform ^

        -set_classification 2 ^

        -i tmp2.laz ^

        -o flagged_classes.laz

 

::---------------------------------------------------------------------------

:: Step 2: transfer the classes to the target file and update the flags

::---------------------------------------------------------------------------

:: Transfer flags as classes to the target file

lascopy -i flagged_classes.laz ^

        -i target.laz ^

        -o tmp_mvflag.laz

 

:: Use a filtered transform to set withheld flag on class 1

las2las -keep_class 1 ^

        -filtered_transform ^

        -set_withheld_flag 1 ^

        -i tmp_mvflag.laz ^

        -o tmp_mvflag2.laz

 

:: Use a filtered transform to set key point flag on class 2

las2las -keep_class 2 ^

        -filtered_transform ^

        -set_keypoint_flag 1 ^

        -i tmp_mvflag2.laz ^

        -o tmp_mvflag3.laz

 

::---------------------------------------------------------------------------

:: Step 3: finally, copy over the proper classes

::---------------------------------------------------------------------------

lascopy -i source.laz ^

        -i tmp_mvflag3.laz ^

        -o finished.laz

 

:: Check the results

lasinfo -i finished.laz

...

histogram of classification of points:

         6441146  ground (2)

         4447709  medium vegetation (4)

 +-> flagged as keypoints: 1081631

  +--->         1081631 of those are ground (2)

+-> flagged as withheld:  34

  +--->              34 of those are medium vegetation (4)

Cheers,

Mike

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[Ryan Comeaux]

Thanks a ton, Mike! Got me going.

[Martin Isenburg]

Hello Ryan.

in the next version of LAStools (to be released in a few days) you will be able to select any number of flags along with the classification:

lascopy ^
-i source.laz ^
-i target.laz ^
-classification ^
-keypoint_flag ^
-synthetic_flag ^
-withheld_flag ^
-overlap_flag ^
-o result.laz

Regards,

Martin @rapidlasso 

On Tue, Jun 9, 2020 at 7:22 PM Ryan Comeaux <ryan.co...@gmail.com> wrote:

Is it possible to copy 'withheld' and 'keypoint' flags along with the classification in lascopy?

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