I have a conundrum concerning LiDAR data, the stored point offset, and the coordinate system.
I process large amounts of LAS data in TerraScan (TS), which sits on top of Microstation (MS). I receive LAS files that are created from raw data by CloudPro. Traditionally, when setting up a project, before importing points, I set the coordinate system up in TS, including any false easting/northing values. I typically set these values to that of whatever coordinate system I happen to be working in (e.g. For NAD83 Virginia South State Plane US_Foot, false_easting: 11482916.667, false_northing: 3280833.333).
I just started working on a dataset in NAD83 UTM 15N meters (false easting: 500000). I set the TS false easting, and began setting up the project. Unfortunately, after some investigation, the LAS files have an x,y,z offset (230247.299, 3550963.700, 0) that will not allow them to fit inside the bounds defined by the 500000m false easting. I understand this is due to MS's coordinate range of +/-2147484 of the defined coordinate origin x,y,z. I also understand that an LAS file's coordinates take the scale and offset into consideration. From the ASPRS specification:
X, Y, and Z offset: The offset fields should be used to set the overall offset for the point records. In general these numbers will be zero, but for certain cases the resolution of the point data may not be large enough for a given projection system. However, it should always be assumed that these numbers are used. So to scale a given X from the point record, take the point record X multiplied by the X scale factor, and then add the X offset.
This got me thinking, how (if any) does the offset of an LAS file relate to the coordinate system that it is projected to?