Priority ranks in geoprocessing implement coordinate ranks. Coordinate ranks are used to preserve coordinates (and, by extension, features) with the highest accuracy. In certain geoprocessing tools (see below), a rank is assigned to each input feature class as an optional value, where 1 is the highest rank. If no rank is given for a feature class, it is given the lowest rank available. If no ranks are provided for any input, all feature classes receive the same rank.
Priority ranks come into play during processing when the distance between features is less than the x,y tolerance. The features with the lower rank will snap to the feature with the higher rank.
There are two sets of tools that use ranks: tools with multiple inputs that explicitly allow ranking to be set and certain overlay and extraction tools that give a higher rank to the input features over the overlay or extract features.
The geoprocessing tools below allow you to specify ranks for the input feature classes:
The geoprocessing tools below do not allow you to specify ranks for the input features; the input feature class will always be ranked higher than the overlay (Clip, Identity, Symmetrical Difference) features. Update is the exception to this rule, as the update features will be given a higher rank over the input features.