According to the pilot, the intent for the flight was to conduct several aerial surveys of large fields. The flight departed with 37 gallons of fuel onboard intended for the 4-hour flight. A diversion was made due to scattered rain showers to wait for weather conditions to improve to the requirements for aerial photography. The engine lost total power about 9 miles from the intended destination. He realized he would be unable to land at his intended destination due to the airplane’s altitude and distance from it, so he performed an off airport forced landing in a field. The airplane touched down and rolled over inverted in a ravine sustaining substantial damage to the fuselage, vertical stabilizer, left wing and right aileron. The pilot reported that there were no preaccident mechanical malfunctions or failures that would have precluded normal operation.