Question about changing the scale factor?
Farwell, Steve - NRCS, Fort Worth, TX
Hello Martin and group, I was wondering what would be the best approach; I have about 4,800 LAS files that I am thinning and want to merge them all into a single LAS file. The problem I am running into is that some of the LAS files have a scale factor of two decimal places and some have a scale factor of three decimal places. I was wondering, is it easier to rescale all of the LAS files to the same scale or sort them and merge then according to their scale factors? I need to create a thinned merged project Overlay layer LAS file for our LiDAR Server? Below is an example of using a thinning merged Overlay layer for the OK Washita River Basin in LiDAR Server:
Thanks for your time.
Steve F.
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Martin Isenburg
for airborne collects such as the one you have there, a scale factor
of 0.001 is a precision overkill since that captures millimeter
resolution, which means you are storing a lot of scanner noise. Most
people will agree that for an airborne collect centimeter resolution,
namely a scale factor of 0.01 is sufficiently precise. With LAStools
you have several options to get the tiles into the same scaling. The
easiest is running one of these variations:
lasprecision -i tiles*.las -rescale 0.01 0.01 0.01 -odix _rescaled
lasprecision -i tiles*.las -rescale 0.01 0.01 0.01 -odir
rescaled_tiles
lasprecision -i tiles*.las -rescale 0.01 0.01 0.01 -odir c:
\uniform_scaling -cores 4
but if you are also thinning then you could also do it all in one run:
lasthin -i *.las -merged -rescale 0.01 0.01 0.01 -step 2.5 -o
merged.las
lasthin -i *.las -merged -rescale 0.01 0.01 0.01 -step 5.0 -o
merged.las
lasthin -i *.las -merged -rescale 0.01 0.01 0.01 -step 7.5 -o
merged.las
of course there are a few other options that i have not listed yet.
cheers,
martin @rapidlasso
ps: pretty bold of you to send a Qcoherent product screen shot to the
LAStools group. (-;
On Jun 15, 8:19 am, "Farwell, Steve - NRCS, Fort Worth, TX"
> Hello Martin and group, I was wondering what would be the best approach; I have about 4,800 LAS files that I am thinning and want to merge them all into a single LAS file. The problem I am running into is that some of the LAS files have a scale factor of two decimal places and some have a scale factor of three decimal places. I was wondering, is it easier to rescale all of the LAS files to the same scale or sort them and merge then according to their scale factors? I need to create a thinned merged project Overlay layer LAS file for our LiDAR Server? Below is an example of using a thinning merged Overlay layer for the OK Washita River Basin in LiDAR Server:
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> [cid:image001....@01CD4ADD.F7C40920]
> Thanks for your time.
>
> Steve F.
>
> This electronic message contains information generated by the USDA solely for the intended recipients. Any unauthorized interception of this message or the use or disclosure of the information it contains may violate the law and subject the violator to civil or criminal penalties. If you believe you have received this message in error, please notify the sender and delete the email immediately.
>
> 33KViewDownload
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> image002.png
> 34KViewDownload
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Doug_N...@fws.gov
Steve,
Be mindful of the ~4 billion point limit for las files. Martin's software helps you work around that limit, so you might not need 1 file.
Doug
Doug Newcomb
USFWS
Raleigh, NC
919-856-4520 ext. 14 doug_n...@fws.gov
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The opinions I express are my own and are not representative of the official policy of the U.S.Fish and Wildlife Service or Dept. of the Interior. Life is too short for undocumented, proprietary data formats.
| "Farwell, Steve -
NRCS, Fort Worth, TX" <Steve....@ftw.usda.gov>
Sent by: last...@googlegroups.com 06/15/2012 11:23 AM
|
|
Hello Martin and group, I was wondering what would be the best approach; I have about 4,800 LAS files that I am thinning and want to merge them all into a single LAS file. The problem I am running into is that some of the LAS files have a scale factor of two decimal places and some have a scale factor of three decimal places. I was wondering, is it easier to rescale all of the LAS files to the same scale or sort them and merge then according to their scale factors? I need to create a thinned merged project Overlay layer LAS file for our LiDAR Server? Below is an example of using a thinning merged Overlay layer for the OK Washita River Basin in LiDAR Server:
Steve F.
This electronic message contains information generated by the USDA solely
for the intended recipients. Any unauthorized interception of this message
or the use or disclosure of the information it contains may violate the
law and subject the violator to civil or criminal penalties. If you believe
you have received this message in error, please notify the sender and delete
the email immediately.
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