AgOpenGPS is an open-source precision agriculture application offering real-time GPS-based field mapping, automated guidance, and section control for farm machinery. It includes AgOpenGPS for field operation visualization and AgIO as the communication hub to external hardware. The system supports multiple guidance modes (AB line, curve, contour), auto headland turning, and up to 64-section implement control using NMEA GPS input. Designed for DIY and commercial use alike, it integrates with custom PCB firmware and steering systems for low-cost auto-steering and rate control.