LIDAR LAZ FILE UPLOAD -TRAJECTORY FILE -TIME DATE STAMP MISSING-ERROR MESSAGE

Hi All 

 I am having the same issues. I have received a las file and the corresponding trajectory files but get a mismatch error.  

Been looking on the net to see how i can convert the SOW time to GPS time but not seen anything that works or really makes sense. 

These are the time stamps i have on my .txt file and the Las file is saying it should be 1.35446e+09

Any idea what conversion method you should use or work flow. We have spoken to Bentley and DJI both say its the others problem. 

Pete

Hi @ Peter Jackson. You can use LAStools: https://rapidlasso.com/lastools/ 

If you are struggling I can help in Terrasolid. 

Regards,Jason. 

Thanks Jason 

So Lastools should be able to solve the conversion / mismatch issue. ?

Yes, LAStools can convert your point between SOW and GPS and update the global encoding. If you need to change your trajectory I would do that in excel. 

Hi, i got LiDAR dataset from Zenmuse L1, can you give me step by step how to solve the mismatch issue using lastool or excel?

Hi Eko, you need to make sure your trajectory and point cloud have the same time. You can use Las info to find out what the global encoding stamp is inside your .las file. Once this is known (in some examples I have it is 1) you need to ensure your trajectory is in the same format. See some useful links here: https://support.geocue.com/las-global-encoding-bytes-explained/ https://www.labsat.co.uk/index.php/en/gps-time-calculator 

Hi, thx for the guidance, so from DJI Terra i already get the .las and sbet.txt with time in SOW as picture below

and i check with lasinfo, the global encoding is 1

so what do i do from here?? what do i need to convert? im sorry for the trouble, kinda new into this, and thx for sparing your time helping me

Hi, thx for the guidance, so from DJI Terra i already get the .las and sbet.txt with time in SOW as picture below

and i check with lasinfo, the global encoding is 1

so what do i do from here?? what do i need to convert? im sorry for the trouble, kinda new into this, and thx for sparing your time helping me

Hi Eko Setiawan , so you have a point cloud which indicates GPS Time (global encoding 1) and your trajectory is Seconds of Week. The easiest way is probably to change your trajectory, rather than your point cloud. You need to convert your trajectory from Seconds of week to GPS Time and convert radians to Lat Long. There are lots of different ways of doing this, including in excel. Typically we have completed this process using Terrascan software. 

hi thank you very much for the respons, in labsat, where do I input SOW to get GPS Time? I try inputting in GPS Second of Week, then stuck there, I don't know which value should i use for the correct timestamp, is there any formula that you can share for converting in excel for time and lat long?

about TerraScan, if i use that software, can i export the correct trajectories from there? and using said trajectories in contextcapture?

Hi Eko Setiawan , I would suggest using TerraScan if possible. In their software package it is possible to change the timestamp format of both the trajectory and point cloud as well as re-project your data to various coordinate systems. This is likely to be the best solution as there are many potential sources of error when completing these multiple conversions in excel. 

Hi Jason Hagon , thank you for your guidance, can you point me to a guide for the process needed to be done in TerraScan for  correcting the timestamp?

Please see information here: https://terrasolid.com/guides/tscan/convert-time-stamps.html?q=time 

This can be completed for trajectories and point clouds.