THE RELATIONSHIP
Geographies are many-dimensional. Each point in a given geography's framework is defined using many different measures. But while you might think that space is no more than just such a geographic dimension, you can also look at space much more completely. Space permeates, defines, and is defined by every one of a geography's dimensions. Space is meta-dimensional when it comes to geography.
The most accessible concept of geography is its original one, the description of the surface of the Earth. This description includes political, topographical, meteorological, and many other dimensions. Each, it seems almost absurd to say, is defined in spatial terms: nation X has such and such a shape, its capital city is so many kilometers from the western border, etc. We don't usually realize, though, that each dimension in turn defines space in some or in many ways. Nation Y's roads are such and such a standard width, so its buses must be so many meters wide, and therefore their seats tend to have this or that much room between them, or this or that shape.
This is how geography defines space, rather than just the other way round.
And as you can see, such considerations easily redound upon each other—one space causing another space causing another. The difference in rail gauge between Germany and Russia before World War I was a major consideration in German war planning – in the German Army's use of space; in the outcome of the war on the Eastern Front. And indeed, the Russians' use of space in war, or more technically speaking their use of geography, is legend in military history.
On a more intimate level, geographies have obvious and profound impacts on individual space. It takes only a moment of thinking about it to see that it's so. Ascending a high tor explodes your personal space exponentially (an overused word, but in this case quite literally correct). Enter a gorge or ravine and space becomes largely vertical, reaching to a perhaps distant sky above but hemmed in on either side. Or how about a little topography? A nice, average forest defines a restrictive space around you radically different from the heart-freeing air of a mere meadow.
So, if geography is defined by space, but space is also defined by geography, are they in a co-dependent relationship? Or are they just one?