To make sure that the original data from your sounding remains untouched, all modifications on the raw data are stored in a separate folder, which is the "Modified" folder.
Files in the "Modified" folder are generated when modifying your raw data files using the "Create Sounding Wizard".
The "Create Sounding Wizard" allows you to correct your data, apply offsets and generate soundings from your original raw sounding data.
The "Soundings" folder is used to store the soundings created with the "Create Sounding Wizard". This are the files which are used to generate volume reports, contour maps etc.
