A vs B vs C vs D neighborhoods?

[Aaron W.]

New real estate investor looking for properties.  How do you know the difference between an A, B, C, and D neighborhood?  I believe an A neighborhood is pretty straightforward as a high end, expensive.  A D is what I have heard called a "war zone".  

How do you define the difference between these neighborhoods and how do I do a search for these different neighborhoods without physically being in these cities if I am doing an initial real estate search (i.e Google Maps, etc.)?

[John Warren]

@Aaron W. I like to think of them like this:

A- Where you want to live. This area has great schools, great amenities, great access to transit or roads, etc. This area has your boutique restaurants, and independently owned coffee shops. 

B: Where you would be ok with living. This area is a safe neighborhood, and the vast majority of people live in areas like this. The schools may not be as good, or the area might not be as nice. This area has a lot of chain restaurants that appeal to the masses. 

C. This is an area where you could live if you needed to, but you wouldn't be thrilled. This area is probably safe, but is mostly the "working poor". The restaurants here are all fast food, and your quality of life isn't as good. The people are decent folks for the most part, but they will have more struggles paying rent as their financial life is not in order. 

D. Collect rent with a gun. Don't invest here unless you really, really know what you are doing.