Decomposed granite soils，which are distributed widely around Hiroshima City，have a great influence on local public works. However，the distribution is difficult generally to determine and presently the numerical value corresponding to boring exploration here and there is accepted as the soil factor of the whole area. As a method for solution of these problems，remote sensing techniques are called to mind. Since these use aerial observation，they have the following advantages，namely they can survey a wide area at a time，and by analysis of the results of processing this imagery，information of all sorts may be obtained. Accordingly，this paper reports the characteristics of suface soils by remote sensing，based upon MSS data taken on the Yahata River area running through Itsukaichi-Cho，and examining the relationship between the results of image processing by MSS and ground truth data.