Issues with reprojecting to EPSG:6496

[Michael Perdue]

Hi Jochen,

Here is a weird one for you. We are trying to reproject some data from EPSG:6345 to EPSG:6496 and getting some unexpected results. So I did a little testing and this is what I'm observing.

# create a text file with sample coordinates.

>echo 442000.00 5173000.00 400.00 > test.txt

# This answer matches Geographic calculator and appears to be right

>cs2cs +init=EPSG:6345 +to +init=EPSG:6496 < test.txt
26056370.20 702756.99 400.00

# Using the projection abilities baked into lastools.

>las2las -iparse xyz -i test.txt -otxt -stdout -epsg 6345 -target_epsg 6496
24619805.36 761519.62 400.00

# Latools calling the proj library. Huh?

>las2las -iparse xyz -i test.txt -otxt -stdout -proj_epsg 6345 6496
26000000.00 700000.00 0.00

But when I run the same set of commands using epsg 6495 (Same projection, but in meters instead of int ft), now everything agrees. Is there an overflow somewhere???

>cs2cs +init=EPSG:6345 +to +init=EPSG:6495 < test.txt
7941981.64 214200.33 400.00

>las2las -iparse xyz -i test.txt -otxt -stdout -epsg 6345 -target_epsg 6495
7941981.64 214200.33 400.00

>las2las -iparse xyz -i test.txt -otxt -stdout -proj_epsg 6345 6495
7941981.64 214200.33 400.00

Enjoy,

Mike

[LAStools - efficient tools for LiDAR processing]

Hi Mike,

thanks for this very detailed report of the issue. We can confirm the problem. Short answer would be: This is not supported.
With text input we do not have header information (like with piped input) and with piped output we can not create a header after the conversion but have to know the boundaries on the fly.

With pipe_in/pipe_out las2las usually gives this error: "ERROR: input and output cannot both be piped". Unfortunately this is not reported in this situation.

LAStools is primary designed to work with LAS/LAZ files. 

The problem are different dynamic header x/y/z offsets. If there will be an offset change combined with pipes and TXT the conversion fail right now by design.

Anyway, we see this is a use case which may should work - so we try to fix this. It is a tricky one, so please be patient for some days.

Cheers,

Jochen @rapidlasso

[LAStools - efficient tools for LiDAR processing]

Hi Mike,

thank you for your patience. We did a change to the las2las conversion logic which hopefully improves this kind of conversions without having side effects to other functionalities.

Please check this beta out:

    las2las64.exe

If everything works as expected we will integrate this change into the official repository and into the next release.

Cheers,

Jochen @rapidlasso