The horizontal factor influences the total cost of moving into a cell by accounting for any horizontal friction encountered. Determining the horizontal cost for each cell is a two-step process. First, the prevailing horizontal direction is defined by a horizontal-factor raster. The values are in degrees and range in value from 0 to 360. Once the prevailing horizontal direction is defined, the horizontal relative moving angle (HRMA) is calculated. The HRMA is the angle difference of the direction of moving into a neighboring cell and the prevailing moving direction defined by the horizontal-factor raster for the processing cell.
Make sure that there are no values in the horizontal-factor raster greater than 360. The documentation for How PathDistance works gives more information on the formatting of the parameter file.