Lasduplicate GPS time precision question

[Bobby Riley]

Hi Jochen,

I have a question regarding lasduplicate. I have a lidar dataset where the GPS time precision extends 7 digits, example below.

Using las2txt, when I convert points to XYZIT, below, 6 digits of GPS time precision is reported.

My questions are:

Does lasduplicate only consider GPS time as far as the 6th decimal place?

If so, is there a way to extend/force the precision lasduplicate employs to the full precision of the GPS time available within the dataset?

What we have encountered is the generation of what have been deemed duplicate points by lasduplicate, but is actuality may not be duplicates due to truncation/rounding as the full range of GPS time precision may not be fully utilized.

 Thank you,

Bobby

[rapidlasso LAStools]

Hi Bobby,

internally all LAStools working with GPS time values as double values with a dynamic count of decimals. This meets the requirements and how GPS time values are stored within the LAS file according to the specification. This means, all calculations should work correct. If you do not think so, please provide a small sample of data and the description which commands you did run and what result you do expect. Then we can have a close look and can see if there is maybe a problem within the calculations. Comparing floating-point numbers is not a trivial matter, so probably we can improve this.
The export using las2las64 or las2txt64 is rather informational. We can think about to extend the decimal places there if this is really requested by the users of LAStools.

Cheers,

Jochen @rapidlasso