Last week I stumbled across this gem on YouTube -
It is a slightly dry film put out by the US Geological Survey in 1955 showing the modern (for the time) processes developed for natural resource analysis using aerial photography.
The guy narrating it sounds about as excited by his work as a dry goods salesman discussing the newest laundry soap. Zzzzzzzzz...
But once past the dry narration I was interested by the methods demonstrated for geological, hydrological, soils and forestry analysis. What struck me was that these were the precise methods we were taught at the Defense Mapping School as late as the early 1990s. These photo analysis processes formed the basis for what we called Terrain Analysis, and in fact my job title for much of my Army career was Terrain Analysis Technician (MOS 215D).
This film approaches each type of analysis as an independent process - an end in itself. We carried the analysis to the next level and merged the output from each of these four disciplines, mixed in some military-specific data like vehicle off-road capabilities, tossed in some road network analysis, some urban analysis and a pinch of weapon systems analysis and produced what we called a military terrain analysis. Our products were usually delivered in the form of map overlays known as a combined obstacle study. The process was very labor intensive and usually tightly focused on specific geographic areas like the Fulda Gap in Germany or the Koksan Bowl in Korea, natural movement corridors that had been used by armies for centuries.
Soldiers going into the Army's Terrain Analysis field received extensive training in field identification methods like geological and soils analysis, hydrological analysis and route engineering studies. They were taught to observe, test and measure in the field using a variety of hands-on methods. Next they moved to the classroom and were taught advanced aerial photo analysis techniques and applied their field knowledge to what they saw in the photos. It was hours and hours of peering at photos through stereoscopes, analyzing texture, tone and pattens to develop a detailed analysis of the terrain and it's impacts on military operations.
Computers have taken on the burden of much of this analysis, and today you can feed a digital image into a sophisticated image analysis package like ERDAS Imagine and have it analyze huge swaths of territory in a small fraction of the time it took using the old manual methods shown in the film. Still, it is fun to see how things were done in the good old days when men were men, hardhats were made out of aluminum and the science of aerial photo analysis found new applications in the civilian and military worlds.