Script to run through a Mongo collection with some malformed geometries and flag and unset the geometries

find_malformed_geometries.js

for (i = 0; i < 139; i++) {
  db.basemap_clean.ensureIndex({ geometry: "2dsphere" })
  db.basemap_features
    .find({ clean: { $exists: 0 } }, { "geometry": 1 })
    .limit(500000)
    .forEach(function (feature) {
      db.basemap_clean.insert(feature);
    });
  db.basemap_clean
    .find()
    .forEach(function (clean) {
      db.basemap_features.update({ _id: clean._id }, { $set: { clean: 1 } })
    });
  db.basemap_clean.drop();
}

db.basemap_features.find({ clean: { $exists: 0 }}).forEach(function (doc) {
  db.basemap_features.update(
    { _id: doc._id }, 
    { $set: { malgeo: doc.geometry }, $unset: { geometry: 1 } }
  );
});