Converting las files from version 1.2 to 1.3

Question

I have lidar data set which initial waveform data is in LAS 1.3. The classified point cloud needs to be delivered in the same version, but my processing software (TerraSolid V15) allows me to write point cloud only in LAS 1.2.

I am afraid processing LAS 1.3 to LAS 1.2 may lose the information of returns greater than 5 (possible returns 6 and 7). Will this make any big difference in the final output? And is there any software/tool that can save LAS 1.2 to LAS 1.3.

It may sound silly, but will it make sense processing LAS 1.3 in LAS 1.2 and then change it back to 1.3 again?

Answer 1

The only difference between LAS 1.2 and LAS 1.3 is the ability to store returns together with a references to the full waveform data. This ONLY is the case for point types 4 and 5. Most of the time people use point types 1 or 3. In this case (if you use point types 0, 1, 2, or 3) there is no difference between LAS 1.2 and LAS 1.3. If you need to "upconvert" from LAS 1.2 to LAS 1.3 you can do this with the free and open source las2las tool of LAStools.

Just follow this example (for LAS 1.4) but leave out the command that changes the point type.

Answer 2

Unfortunately TerraScan does not have full read/write capabilities for LAS specification after version 1.2. Unless you have access to GeoCue and/or LP360, you must process and classify your pointcloud in 1.2 and then convert to 1.3/1.4 at the end.

GeoCue released some documentation about this. While not specifically about 1.3, Lewis Graham discusses 1.4 here.