Estimating the size of an army

What skill do you think is appropriate for estimating the size of an enemy army from a distance? I want to say soldiering, but it doesn’t quite fit that description. I went with my gut on it, but I’m curious what others think.

tent counting-wise =P

I think it’d come down to how the intent was framed.

Tactics perhaps? Or strategy? Maybe even straight-up Perception.

Logistics?

Soldiering works as well, I think - anything rooted in Perception and not too outlandish should do.

First ask - should it require a test?

Soldiering is a great choice – if you can get a look at their marching order or their camp.
Logistics is a good one too – if you can get a look at their supplies.
Observation is the stock and trade of spies – if you can watch them pass and count the units or get a vantage on their camp.

I thought Observation was specifically for finding hidden things or people? Wouldn’t it just be plain Perception for counting units as they pass?

Y’all are thinking modern. Obviously the correct skill to test is Heraldry: Identify the banners and you know how many men follow those lords.