A data processing apparatus comprises a first memory configured to store at least one data set; a second memory configured to store a multi-channel atlas texture; and processing circuitry configured to: store at least one region of the at least one data set in one or more corresponding regions of the multi-channel atlas texture by altering data values of the at least one region of the at least one data set in accordance with a transformation vector comprising at least one channel weight and/or at least one numerical offset value; and reconstruct data values from the altered data values by transforming the altered data values using the transformation vector.