These electronics cause chroma values to superimpose over brightness (luminance) changes of the picture. Welles decided to superimpose snow falling to mask the graininess in these shots. Some can superimpose sonar and map data from GPS position. Pilots can choose to superimpose the weather radar picture on the displayed route. It is important to superimpose the radiograph on a stable anatomical structures. Longer exposures superimpose rapidly changing features, and often blanket the dynamic attribute of a display. Some examples of bitonality superimpose fully harmonized sections of music in different keys. In general, the beta-sheets are well-preserved and the crystal structures superimpose in these areas. It was agreed upon to superimpose the plain flag with additional white Olympic rings.