When data is originally added to LP360 the selected files will be grouped into layers, depending on certain criteria, so that only compatible LAS files will be on a single layer.  Criteria required for compatibility include: * The coordinate system (when available) * LAS format version * Point Data Record Format (PDRF) * GPS Time format LAS files must have these 4 criteria in common to be considered compatible and grouped into the same layer. LP360 will create as many layers as necessary to represent each file selected to be opened. The file list displays detailed information in columns for every LAS file selected to be added. This information is extracted from the LAS File or raster file header. You can click the columns to sort the data and then see which files are compatible (based on the criteria listed above). By default, only basic information columns are displayed, but you can click the Show Advanced Column button above the window to display much more information. For additional information concerning combining data onto one layer within LP360 please review Putting LIDAR data on a single Layer.