Solr - How do I construct a query that requires a NOT NULL Location field

Question

I have a Solr index with a set of coordinates stored as a Location type; I would like to query for documents where this field has a non-null value.

What is

Answer 1

You can add this to your query fieldname:['' TO *]. This will be the equivalent of a NOT NULL check.

I got this from the post - Solr - Field Not Null Searches