A data set may be represented by samples of multiple resolutions, such as an image represented by pixels of various resolutions. When such multiple-resolution samples are potentially overlapping, it may be inefficient to render both a lower-resolution sample and also the plurality of higher-resolution samples that overlap the lower-resolution sample. Conversely, it may be more efficient to determine, before rendering a sample representing a particular data unit, whether the sample is overlapped by available higher-resolution samples that represent the same data unit. Techniques are disclosed for making this determination in an efficient manner, and for acting upon the determination to achieve improved efficiency in the rendering of the data set.