In an embodiment, a data processing method comprises receiving permanent properties data for a plurality of agricultural sub-fields of an agricultural field； determining whether at least one data item is missing for any sub-field of the plurality of agricultural sub-fields in the permanent properties data, and if so, generating additional properties data for the plurality of agricultural sub-fields； generating preprocessed permanent properties data by merging the permanent properties data with the additional properties data； generating filtered permanent properties data by removing, from the preprocessed permanent properties data, a set of preprocessed permanent properties records corresponding to a subset of the plurality of agricultural sub-fields in which two or more crops were grown in the same year； applying a regression operator to the filtered permanent properties data to determine a plurality of intra-field variations values that represent intra-field variations in predicted yield of crop harvested from the plurality of agricultural sub-fields.
