After talking with a local guide ...they each pulled out a 17, 16, and 18 inch wild brook trout in that order.
Couple thoughts:
First, before you lay any money down ...if that ever crossed your mind... unless that place has a large amazingly productive water associated with it -like a lake, pond, or beaver pond- those numbers are hyperbole at best.
In the east, I did most of my reconnaissance by hoofing, but did use maps and satellite images some. Here in the "big open" west I use them much more.
In the east I found topo maps and satellite images useful to find habitat parameters like bigger deeper pools, steep gulches or swampy lowlands that might indicate groundwater influx, or expanses of forested stretches that offer intact habitat and shade. Nothing beats hoofing though. Springs are easiest to find in dead of winter, and also in early summer mornings when good springs can create mist -sometimes a lot of it. There is one such stretch I can see through binocs from my mountainside home from miles away (I’m in CO and can almost see Kansas from where I’m at) that on some mornings is hugged by a layer of cloud along its course. Fun story actually:
I hiked down there once to check it out, and through the massive willows I saw line flash! An angler was in there. I watched him for a bit, a spin-fisher, and as I was working my way around him, he spotted me. “Ohhhhhh! You found my SECRET SPOT!!!!” he wailed. He obviously had kept this bottled up for some time, and was dying to tell…someone! He practically blurted out that he’d caught a 16 and a 23 inch brown there. I don't remember if he asked me not to tell –he didn’t have to– I have never told anyone where it is. As I passed him I noticed the stretch was alive with rising browns, whereas the rest of the stream, for miles in either direction, in the mid to upper 60s, was “silent”.
On high country streams here in the Rockies, map research can be especially important bc of the amount of potentially rugged hiking involved. I look for gradient and channel shape mostly, as too steep and its virtually unfishable, too straight and there will likely be few pools. Also, there is a bench area that exists on high mountain streams below the initial descent from on-high, and before it breaks down the foothills, characterized by flatter gradient with settled flow that allows sediment and soil to build boosting productivity and allowing pools to be scoured. The fishing in these stretches tends to be spectacular.
Here’s a trip report that describes large scale topographic habitat parameters that matter:
http://www.troutnut.com/topic/2413/In-the-Willow-Jungle
I also use map and satellite for hunting –I use them to find snowshoe hares, mountain cottontails, deer, and elk habitat. This winter I found my way into a great mountaintop that was surrounded by private property. I used our county property ownership site to find a narrow (and steep-sided) corridor that got me in without trespass. It required a route that no one would comfortably hike, along one edge of a very steep mountainside. And I ended up following a pair of boot tracks in the snow, just a couple days ahead of me, taking the exact same route. It was obvious that someone else had done the exact same map work! It felt a little … eerie…; Like I was inside someone else’s head, and vice-versa.