Insets specify a distance from each edge of a rectangle. 插入指定的距离，从矩形的每一边框。
The rectangular section of the inverse Distance Weighting has the lowest result in interpolating signal strength and difference of locating errors. 而矩形分区距离反比权重式内插演算法，内插出的无线电波地图用来定位能达到最好的精准度。
