Representation in 2D of DSC classification results of the Combmod classifier compared to new combination of the DSC classifiers Combmod-α evaluated on the cleaned validation data set as a function of Galactic latitude and brightness. In each subplot, left and right two panels refer to the completenesses and the purities of the extragalactic classes, respectively. The number of sources per target class in the cleaned validation set are reported in Table A.2. (a) Combmod using the global prior (average 2D completenesses of 92% and 95%, and 2D purities of 55% and 88%, for the quasar and galaxy classes, respectively). (b) Combmod-α using the global prior (average 2D completenesses of 82% and 93%, and 2D purities of 79% and 93%). (c) Combmod using the variable prior (average 2D completenesses of 95% and 96%, and 2D purities of 57% and 86%). (d) Combmod-α using the variable prior (average 2D completenesses of 89% and 94%, and 2D purities of 74% and 90%).