Trouble aligning drone LiDAR with public datasets projection issue?

[lightdataworks484]

We've been testing our new drone-mounted LiDAR setup over the rural areas of Idaho, and we aimed to compare our point clouds with some publicly available terrain data. I downloaded a few DEMs and LAS files from the state GIS portal, but when I tried to line them up in Global Mapper, our scans were way off, like several hundred miles off.
Could it be that the public data is in a different format? Has anyone else faced a similar misalignment problem when trying to combine different sources? I'm curious if it's just a projection issue or something more complex

 

[Berth]

Yep, that's almost definitely a projection mismatch, check the coordinate system on both your LiDAR and the public data, one's probably in WGS84 and the other in a state plane or UTM zone

 

[_puddnpie]

Yep, that's almost definitely a projection mismatch, check the coordinate system on both your LiDAR and the public data, one's probably in WGS84 and the other in a state plane or UTM zone

yeah, I think it's definitely a projection mismatch, but it could be more than just the coordinate system.
OP, make sure you check all three parts of the projection: the datum (e.g., NAD83 vs WGS84), the projection (e.g., State Plane vs UTM), and the units (feet vs. meters).
A hundred mile difference could even be a US Survey Foot vs. International Foot issue. The key is to find the metadata for both your data and the public data and make them identical in Global Mapper before you try to align them

 

[Hamihaze1]

In addition to what the others have said, I also read that with some datasets you may need to do some manual tweaking and alignment to get things perfect.