MikeC;
Other than in a few rare incidents I really can't see that things like military encampments, military trenches or frankly anything to do with military formations had much at all to do with very early architectural thinking that lead to the brief style of architecture commonly referred to as the "geometric era".
If one follows the basic thread on this era in Cornish and Whitten it seems pretty obvious that the "geometric era" was likely a result of much more mundane reasons.
The enormous explosion in the amount of golf courses between the very first few in the 1890s into the 1900s (C&W cites 80 courses in America in 1896 and 982 in 1900, and many times that amount into the 1900s before the creation of a golf courses that we might consider somewhat naturally inclined and good architecture like NGLA) needs to be looked at carefully to see how and why so many came to look as they did--ie, very rudimentary geometric architectural features.
Almost all those early courses in that era were called "lay out" courses where generally fast traveling architects who were never to return (Bendelow, Findlay, Tucker, et al) spent less than a day staking out routings that were very simply measured and staked. The differences in those courses that were so prevalent and what some of us think of as interesting early architecture is obviously enormous.
The inclusion of "design" or "architectural" features were almost always left to the people of the club (who knew nothing about architecture) and it seems clear that features such as bunkering was almost always a result of simple cut and pile operations, be it cut dirt and berms or rocks and mounds and berms with cut dirt or even stone walls and such that really took no architectural imagination.
From what I've seen of these old rudimentary designs such as Marion G.C. and such the modus operandi seemed much more a result of man's natural instinct to make orderly features or possibly far more the influence of a sort of "steeplechase" look (probably the result of the horse world and its influence) than any military influence. It's amazing how much Marion G.C. which really has not changed looks like a steeplechase course and nothing remotely like someting to do with the military.
The architectural influence of trying to make golf features (man-made architectural features) look something like nature by mimicing or utilizing the basic random lines of nature was obviously just not thought of in that early era by the people rapidly manufacturing those features.
I had a conversation recently with Doug Fraser, originally of the Atlantic City C.C., and a man who obviously knows as much about the evolution of that course as anyone today and he stressed and confirmed that when any of us look at the design of that course originally (and so many like it) by someone like John Reid, we really do have to force ourselves to understand just how rudimentary things were then and how rudimentarily things were done then compared to the way we look at design and architecture today even when looking back from today at that time.
But a comprehensive or prevalent military influence on the way those things were done in golf architecture back then? I really doubt that was true with any prevalence at all unless someone doing something on those courses happened to have a military background which was also likely very rare.
And if we look back at that era in the context of military thinking or influence there wasn't much at all going on militarily in that era anyway.
I truly believe the early influences on golf architecture of that early era were some interesting ones but very rarely military.
And we can't forget either the influences of very rudimentary architectural ideas from the old country (from the wave of the early immigrant journeymen clubmakers/greenskeeprs/designers) which were probably not much more than man attempting to sort of support the things of nature for golf, things like boards and sleepers and things such as that supporting disintegrating dunes--all often very rudimentary and often geometric--ie the man-made features.