An initialized graphical user interface program can produce a plurality of parameter input fields in a graphical user interface. The plurality of parameter input fields can be logically grouped with similar parameter input fields in close approximation to each other in the graphical user interface. The graphical user interface program can then receive a plurality of parameter data from a user can input into the parameter input fields of the graphical user interface program. Based on the received user input parameter data, the graphical user interface program can deactivate one or more parameter input fields. The graphical user interface program can error-check the received input data and provide warnings for any incorrect data. Finally, the graphical user interface program can generate a fort.15 input file based on the parameter input data.