The present invention is a method of generating a geologic model which incorporates a local spatial trend in rock property continuity. Initially, a candidate geologic model is generated by assigning a rock-property value to each block of a model grid. Next, local spectra which characterize the desired local spatial trend in rock property continuity are specified. These local spectra are used to frequency scale the rock-property values of the candidate geologic model. The scaled rock-property values are then combined to generate a scaled geologic model that incorporates the local spatial trend in rock property continuity.