Laying out large-scale irrigation systems is not just stretching out hose and turning on the water for two hours.  It requires a thorough understanding of the formulas that govern pressure, water flow, friction loss formulas and careful diverse engineering.   Part of the design work involves studying graphs of the effects of land slope and the graduating diameter of successive segments, row spacing and many other factors related to predictable water flow at every emitter.

Here is the Main program with two of its child forms after conversion from VB for DOS to VB6 for Windows:

Toro's Converted Main MDI form snapshot