There are four options for numeric method: Product to the nth root, product, mean, and minimum (Figure 71). Please note that multivariate analyses in HEC-EFM and the associated numeric methods are intended to work with ecovalue time series based on suitabilities between 0 and 1.
Figure 71. Numeric methods for multivariate analyses.
For each time step:
Product to the nth root combines ecovalues by multiplying the ecovalues of each selected pairing and then taking the nth root of that product.
Product combines ecovalues by multiplying the ecovalues of each selected pairing.
Mean combines ecovalues by summing the ecovalues of each selected pairing and then dividing that sum by the number of selected pairings.
Minimum combines ecovalues by selecting the minimum ecovalue of all selected pairings.
