In this question:
Getting the projection of a LAS file using liblas?
Howard Butler (liblas developer) said that:
To be honest, I think the easiest way [Getting the projection of a LAS file using liblas python API] would be to shell out to lasinfo with the --xml argument, and then use ElementTree or some such to pluck out what you need from the XML.
You can also use lasinfo with the --no-check argument to filter ESPG code. I tried out it (bash console) with this Autzen_Stadium.zip las file and it works well.
lasinfo --no-check /home/zeito/pyqgis_data/lidar.las|grep -i epsg
AUTHORITY["EPSG","2994"],
Editing Note:
By using liblas in a script (Python Console of QGIS), I found out one way to read a file's spatial reference within its header's file.
from liblas import file
input_file = '/home/zeito/pyqgis_data/lidar.las'
f = file.File(input_file, mode='r')
header_file = f.header
srs_file = header_file.srs
print srs_file.wkt
whose result was:
>>>execfile(u'/home/zeito/pyqgis_scripts/lidar2.py'.encode('UTF-8'))
LOCAL_CS["NAD83(HARN) / Oregon Lambert (ft)",GEOGCS["NAD83(HARN)",DATUM["unknown",SPHEROID["unretrievable - using WGS84",6378137,298.257223563]],PRIMEM["Greenwich",0],UNIT["degree",0.0174532925199433]],AUTHORITY["EPSG","2994"],UNIT["foot",0.3048]]
I don't believe there's an option to convert any file format to LAS within ArcGIS, out of the box.
You can support this idea (there are also additional suggestions on the page): https://geonet.esri.com/ideas/4809
Best Answer
Update:
Depending on the ArcGIS version, some LiDAR tools will allow reprojecting through the Environment settings: Output Coordinate System.
For example, the Tile LAS tool:
Original answer:
LiDAR (.las) files and LASdataset files (.lasd) cannot be reprojected within ArcGIS.
A .lasd file is a LAS dataset file developed by ESRI.
According to ArcGIS Help 10.1 one can set a spatial reference to a LAS dataset going to the ArcCatalog, LAS Dataset properties, and then,
XY Coordinate System tab.However, this won't change/reproject the actual .las files. It is only recommended when the .las files do not originally contain the spatial reference and one knows which CRS they belong to.
Strongly recommend reading: LAS dataset considerations - Spatial reference, which includes ESRI's constraints about this topic.
Alternatively, there are other software which will allow reprojection of .las files (example).