Graphic data conversion method

Claim 1

A data conversion method for converting graphic data of a first format into an intermediate format and storing the converted data in an intermediate file to facilitate subsequent conversion to a second format, the graphic data representing graphics which include a plurality of views, said data conversion method comprising the steps of: a. decomposing the graphic data of the first format into graphic form elements, each graphic form element being selected from a group consisting of a point, a straight line, a polyline, a circle, a circular arc, an ellipse and an elliptical arc; b. storing in the intermediate file at least one composite graphic form, each composite graphic form representing a plurality of portions of the graphics which portions are similar to each other, each composite graphic form including at least one graphic form element; c. registering the at least one composite graphic form for repeated use by storing in the intermediate file in association with each composite graphic form a corresponding symbol; d. converting the decomposed graphic data into unit graphic forms, each unit graphic form representing the graphics of a corresponding one of the views, the unit graphic forms being expressed in terms of the graphic form elements and the composite graphic forms, at least one of the unit graphic forms being expressed as a combination of at least one composite graphic form and at least one graphic form element, wherein each of the composite graphic forms of the unit graphic forms is represented in the unit graphic forms by the corresponding symbol; and e. storing the unit graphic forms in the intermediate file separately from the stored composite graphic forms.