In this recipe, you wrote a Python function in PostGIS, using the PL/Python language. Using Python inside PostgreSQL and PostGIS functions gives you the great advantage of being able to use any Python library you wish. Therefore, you will be able to write much more powerful functions compared to those written using the standard PL/PostgreSQL language.

In fact, in this case, you used the urllib2 and simplejson Python libraries to query a web service from within a PostgreSQL function—this would be an impossible operation to do using plain PL/PostgreSQL. You have also seen how to overload functions in order to provide the function's user a different way to access the function, using input parameters in a different way.