Abstract: A method is provided for devising a floor plan of an existing building in which angles and distances are measured from an interior traverse point. A surveying instrument is set up at a selected traverse point and distances and angles are measured to prominent points on the interior walls. Additional set ups are made to other interior portions and referenced to each other in order that the prominent portions such as corners of the walls and ceilings and the like may be measured and collated in the computer data collector. The traverse points, angles and distances are recorded in a data collector, transferred to a computer and by means of software are plotted on a coordinate field and with a computer aided design drafting system printed out on paper to provide a floor plan of the building. The surveying instruments employed may be an electronic distance measurement instrument and a theodolite for measuring angles which may be combined in a total station instrument.