Discrepancy of offset in ept.json vs LAZ metadata

connormanning / entwine

Entwine - point cloud organization for massive datasets

https://entwine.io

Other

433 stars 128 forks source link

Discrepancy of offset in ept.json vs LAZ metadata #245

Closed wonder-sk closed 10 months ago

wonder-sk commented 3 years ago

I am seeing different values reported for "offset" of Y dimension in ept.json compared to what is then stored in .laz files of the octree (e.g. the root node 0-0-0-0.laz).

in 0-0-0-0.laz metadata: -1204300
in ept.json: -1204303

If the client's parser trusts offsets from ept.json, this causes unwanted shift of 3 meters.

Offsets of other dimensions seem to match in my particular test data (15 MB): https://drive.google.com/file/d/1Zs3cLikFX2UWIbk5fIrlc4NhWN_zll2D/view?usp=sharing

connormanning commented 3 years ago

The root cause of this issue is pdal/pdal#3235. Entwine sets these offsets here, and in this particular case, PDAL transits the value -1204303 through the string -1.2043e+06, chopping off the last digit. Unsure of what action Entwine can/should take at this time, but I'll leave this open until it's resolved.

connormanning commented 10 months ago

This has been addressed upstream in PDAL.