A method is disclosed comprising: determining, using a processor, whether a radio model of at least one radio node associated with a data set is incomplete based on a comparison between the coverage area of the radio model of the at least one radio node and a cumulative coverage area generated out of radio models of the at least one radio node associated with a plurality of data sets, wherein a data collection comprises the plurality of data sets and the data collection is indicative to at least one indoor radio map. Further disclosed are a corresponding apparatus, a corresponding system and a corresponding software program.