Remote sensing, and in particular passive microwave, has a great potential for providing areal estimates of soil moisture. It can be implemented with aircraft-based sensors as described here. The result of the measurements, the brightness temperature images, can be converted into volumetric soil moisture maps using additional environmental information. These maps display information on soil moisture distribution over space and time. Semi-variogram analysis was performed to investigate spatial variation of soil moisture and its scale dependence with the environmental features. Analysis revealed a dependency of soil moisture distribution at two scales. On the regional scale, rainfall is the dominant factor influencing soil moisture distribution. On the local scale, soil texture dominates.