Find duplicate unanswered questions where OP from the stub post (source) is the same OP as from the destination post (master/target). Usually, duplicates serve a purpose of linking nearly identical posts in scope so the best/canonical answer can be found. They are useful because since people can ask related questions with different wording, there are more chances the result of a search leading to one of the dupes (and then, the canonical answer). HOWEVER, duplicate questions asked by the same OP* are likely to have the same wording and therefore, the corresponding stubs are useless to the site. Those should be purged (flag for moderator attention or cast a delete vote, after confirming it is a useless question)! *Usually this happens because OP asks, then nobody answers, then he/she asks the same Q again instead of improving the first one (there are exceptions, this is why results from the query should be reviewed carefully).
Q&A for cartographers, geographers and GIS professionals