The first and arguably most important point to note is that this is an old classic about Australia. She doesn't mention the country's name, but you're supposed to work it out if you don't already know. 
This poem was written in 1904. Which is over a century ago and yet every word still resonates today and just as much as it did back then. 
A "Strong love of grey-blue distance" speaks for the size and space of the country and against the relative claustrophobia that smaller, more peopled countries have to deal with. Her affection for this country has an extremety bourne in and of the land itself. She loves the good of it: the sweeping plains, the mountains and the 'jewel-sea' and all the resplendent beauty there for you to see.