Mongo stuff

# Get the average classification counts for each group of subjects in Galaxy Zoo

db.galaxy_zoo_subjects.aggregate([{$group : {_id : "$metadata.survey", nClass : {$avg : "$classification_count"}}}])

# Export data from MongoDB to a CSV file from the shell command line

mongoexport --db ouroboros --collection galaxy_zoo_subjects --csv --fields classification_count --query '{"metadata.survey":"ukidss"}' --out ukidss_nclass.csv