Leon Mauldin has posted a great aerial photo of Khirbet Qeiyafa overlooking the Elah Valley. You can see it at Leon’s Message Board.
The tree line of the Elah Brook is very obvious in the valley. It is the brook where David got his “five smooth stones” to fight Goliath in 1 Samuel 17. The brook may have been an obstacle dividing the Philistine and Israelite armies. Why did they go at least 40 days without a battle? Possibly because it was dangerous to mount an attack across the brook. Here is a photo of the brook ravine during summertime.
Notice the depth of the brook bed and the steepness of the slopes. The brook may not have been as deep 3,000 years ago, but would still be an obstacle to disrupt a frontal military attack. Defenders could stand on the opposite slope and pelt attackers with deadly force from higher ground. Mountains on both sides of the valley made flanking maneuvers difficult and dangerous. Perhaps this was why the Philistines and Israelites waited at least 40 days without seeking open battle. Goliath's challenge would have seemed a safer, surer bet than an assault across this terrain. (Photo by Luke Chandler)
Bible, Archaeology, and Travel with Luke Chandler 
Ah yes … I can see your keen eye for observations … the wonders of looking beyond the obvious.