1. A computer system implemented method of automatically computing from data received by a computer-based value appraising system an optimal appraisal value of a real estate property, where all of different types of appraisal approaches are used together to optimize a nonlinear objective function, the method comprising the steps of: a) storing, by the computer-based value appraising system, influence factors and a range of influence factor values for each of the different types of appraisal approaches; b) defining, by the computer-based value appraising system, the nonlinear objective function that includes control variables representing the stored influence factors for all of the different types of appraisal approaches; c) using and causing a microprocessor to perform nonlinear programming of the nonlinear objective function to simultaneously optimize the nonlinear objective function for all of the different types of appraisal approaches by adjusting the control variables within the corresponding range of influence factor values; d) determining, by the computer-based value appraising system, an optimal range of appraisal values for the real estate property from the optimized nonlinear objective function according to each of the different types of appraisal approaches; and e) outputting the optimal appraisal value to the user based on the optimal range of appraisal values, where all of the different types of appraisal approaches are used together to optimize the nonlinear objective function.