Conventional soil maps (CSM), as the major data source for information on the spatial variation of soil, are limited in terms of both the level of spatial detail and the accuracy of soil attributes. These soil maps however, contain valuable knowledge on soil and environmental relationships. Such knowledge can be extracted for updating conventional soil maps through the use of available quality data on environmental variables and land use. We used a method to update conventional soil maps using digital soil mapping techniques without additional field work, which can be used in situations where the study area contains no or few soil profile descriptions at set points. The basis of the method is that soil polygons on a CSM correspond to landscape units, which can be considered as combinations of environmental factors. We extracted the knowledge on soil and environment relationships after the updating of CSM by the Geography Information System (GIS). The extracted knowledge was then used for correlation of the soil properties. This method was demonstrated through a case study for updating a conventional soil map of the Kocas State Farm in Central Anatolia, Turkey. The case study showed that the updated digital soil map contained much greater spatial detail than the conventional soil map. Results of this studying are indicating that the proposed method is an effective approach to updating conventional soil maps.