After Fukushima Daiichi Nuclear Power Plant (FDNPP) accident, airborne gamma-ray detection was used for regional mapping of soil contamination. For such surveys, the flight-line spacing is an important factor controlling the quality of contamination maps. In this study, cesium-137 (¹³⁷Cs) ground activity is interpolated and mapped using ordinary kriging method; thereafter the error of interpolation is evaluated as a function of flight-line spacing. The analyses were conducted in six 20 km × 20 km test sites with distance of less than 80 km from the FDNPP. In each site, the ordinary kriging estimators were applied to different selections of flight-lines of decreasing density, then punctual and classification errors were calculated. It is demonstrated that these variables are highly correlated (r² > 0.78): increasing the flight-line spacing for 1 km increases the errors from 3% to 9%, depending on the site location. Therefore, flight-line spacing could be designed as a function of acceptable error, determined in the monitoring objectives.

福岛第一核电站（FDNPP）事故发生后，机载伽马射线探测技术被用于对土壤污染进行区域制图。对于此类调查，飞行线间距是控制污染图质量的重要因素。在这项研究中，铯137（¹³⁷ Cs）地面活动是使用普通克里金法插值和绘制的。此后，根据飞行距离来评估内插误差。分析在六个20 km×20 km的测试地点进行，距FDNPP不到80 km。在每个站点中，将普通的克里金估计器应用于密度递减的飞行路线的不同选择，然后计算出准时和分类误差。证明这些变量高度相关（r ² > 0.78）：将飞行路线间距增加1 km，则误差会从3％增加到9％，具体取决于站点的位置。因此，可以将飞行线间距设计为在监视目标中确定的可接受误差的函数。