1. A method for displaying a three-dimensional configuration of a given part on two-dimensional map data, said method comprising: classifying in advance the three-dimensional configuration of the given part into a plurality of patterns and preparing in advance a transformable three-dimensional map display model for each of the patterns; extracting parameter data corresponding to the given part from the two-dimensional map data; generating model transforming data from the extracted parameter data; and applying the model transforming data to the corresponding three-dimensional map display model to transform the three-dimensional map display model into a desired form, and obtaining a three-dimensional image of the given part.