To reduce the amount of storage space and computing power required to render image data, particularly building image data, primary and secondary colors may be extracted from the image data. The image data may be re-rendered using only the primary and secondary colors. The re-rendered image may be evaluated for patterns, the patterns thresholded to bi-level data and a Discrete Fourier Transform (DFT), or equivalent, may be performed on the bi-level data. Low order coefficients may be discarded depending on level accuracy desired. DFT coefficients and color data for the primary and secondary colors may then be used to construct an abstraction of the original image data, using data that is, in some cases, three or four orders of magnitude smaller than the original image data.