1. A method for creating a collective point-cloud data from a plurality of local point-cloud data, the method comprising the steps of: providing scanner data comprising said plurality of local point-cloud data, wherein said local point-cloud data comprises relatively low-precision positioning data of said scanner; creating a relatively medium-precision collective point-cloud data from said plurality of local point-cloud data; and creating a relatively high-precision collective point-cloud data from said medium-precision collective point-cloud data; wherein said step of creating a medium-precision collective point-cloud data comprises providing external (medium-precision) positioning data associated with each of said plurality of local point-cloud data.