For some LAS files, using the Create LAS Dataset tool works in ArcMap 10.4, but in ArcMap 10.5, the tool fails and returns an error, "Not a Valid file".
There are updates on spatial reference handled in ArcMap 10.6, related to other issues, that also appear to have resolved this problem. The LAS file can be used without complaint in ArcMap 10.6, as in ArcMap 10.4.1. Note though that the file does not contain a valid spatial reference so the file is recorded in ArcGIS as 'unknown'. A .PRJ sidecar file is still needed for the assignment of a valid spatial reference.
解决办法
Note that this issue can be resolved by creating a projection file for the affected LAS files. Use the "Create PRJ for LAS" tool from the 3D Sample Tools found here: <a href="https://www.arcgis.com/home/item.html?id=fe221371b77940749ff96e90f2de3d10" target="_blank">https://www.arcgis.com/home/item.html?id=fe221371b77940749ff96e90f2de3d10</a>When running this tool, select 'Unknown' and specify the LAS file. The tool creates a .PRJ file next to the file location. Once the .PRJ file is created, create the LAS dataset and open the file in ArcGIS Pro.