I'm doing a project based on using Lidar point cloud data and I have access to a DEM that cover all of Sweden. But my goal is to produce several DEMs covering a small area using different interpolation methods. For this I'm working with the LAS dataset toolbox. When that's done I want to compare my own produced DEMs with the DEM that cover whole of Sweden and check for RMSE error.
I'm quite clueless how to solve this since I'm not a mathematician and I'm new to working with Lidar.
I'm using ArcGIS for this.