There are gradients in between.

But you're definitely right, prices between Bridgeport and Midway are a gradient, so as prices rise further east it pushes the prices our west higher.

Keep in mind that since property taxes and insurance are also going up, your cash flows would be influenced by the gradient of change in these two factorsApart from that, another potential risk (on top of what @Taylor Dasch mentioned) (assuming a cash-out refinance per your post) would be lower equity in the deal (depending on how much you pull out) and therefore, a higher possibility of being in the red if the market were to go south  

Credit utilization's affect on score is a gradient and not step tiered, meaning your score would likely go up if you dropped the utilization to 10%.  

I really doubt the gradient sloping away from the house or how far away that extends is enough.

I was following along nicely and then suddenly the information gradient turned exponential and I felt like a deer in the headlights, especially when he talked about "Call Options on Steroids".

In addition, he/she understands heat transfer, pressure gradients they relate to volume, capacity and air flow velocities, state transitions, voltage/amp/resistance as they relate to three-phase, series, paralleled systems, blah blah blah.

And then within RE there are gradients of work.

On the West Side, however, the gradient is pretty shallow.  

Both area's will have duplexes available, a lot of hard working people, and a gradient of crime from "surprisingly a lot" to "surprisingly little" ("border" to "border" i mentioned above).