LiDAR Comparison Methods

[JamesStewart-Moore1]

I am hoping to get some insight from others who are familiar with comparing multiple LiDAR surveys to one another. I have two LiDAR surveys with similar extents that I would like compare for elevation change. I have the point cloud .las files for each of them, so I am able to manipulate the original data in any way that is necessary.

So far, I have created 3 ft. resolution (1/2 the sampling density) rasters for each of the surveys using the same (IDW) interpolation method. I was hoping that by creating a grid of the same size for each of the surveys that I would get rid of any artifacts in the subtraction product. This has not been the case thus far as there is grid-like striping in the subtraction product. These artifacts result in about a +/- 3 feet error in the product. Maybe with a 3 feet grid spacing this is the best that I can hope for??

Does anyone have a comparison method that works well for them?

[CodyBenkelman]

you didn't state if you're using ArcMap or ArcGIS Pro, or what version, and I'm not certain of which tool you used to create your DEMs.

I'm betting your two rasters are not aligned at the pixel boundaries, so your difference raster has moire resampling artifacts.

I'd use LAS Dataset to Raster, generate the DEM from the first LAS dataset, then when you run it on the 2nd LAS dataset, use the Snap Raster (environment setting) and input the 1st DEM.

[JamesStewart-Moore1]

I am using ArcGIS Pro. Will this work if the extents of the two las datasets are different?