@Modawg2k, the most straight forward way to ballpark this is to measure the feet of tubing (if driptube) or emitters (it point source) in your drip zone, then observe the diffusion range of the emitters, bubblers, or misters (micro-sprays) in square feet, then back into the square footage.
Before spending too much time, it might help to define what your goal is with this data? Are you trying to calculate a custom nozzle precipitation rate? Correct the reporting in the app? Or something else?