With Amazon Prime's 2-day shipping, I seldom go to physical stores any more. How do they deliver items so quickly? Let's analyze some data to find out...
There are very few services/memberships that I truly feel like I'm getting "a good deal" for my money - and Amazon Prime is one of them. Amazon has a huge product selection, with detailed information about each product. There's also a good search engine that always seems to work the way I want it to. And they have a large customer base, and the customers frequently post very useful product reviews & ratings. But the feature that impresses me the most is the 2-day shipping! I used to hate ordering things through the mail, because it typically took 5-10 days - but with Amazon Prime's free 2-day shipping, I usually have the item quicker than I could have found the time to drive to physical stores shopping for it.
For example, here's an exact replacement antenna I recently bought on Amazon for my vintage 1980's Conion boombox. Believe me - I could have driven around town for weeks looking in electronics stores, and still not found one!
How does Amazon deliver their packages so quickly? Some claim that they use a fleet of unmanned drone aircraft to deliver their packages. They don't - or at least not yet! (see Amazon Prime Air proposal)
But what they do have is a network of huge distribution warehouses, strategically placed across the US. So, while you're shopping online, they check to see if the item you want is in a warehouse close enough to your location that it could be delivered within 2 days. And, of course, they have people working in the warehouses around the clock pulling the items you order, and packaging them to ship immediately after you order them.
I was curious which warehouse(s) were closest to me, and found a map on the Amazon website. I could see that three states bordering North Carolina have a distribution center, but I couldn't tell exactly where the warehouses were located within each state.
I did a bit more searching and found an article that listed the addresses of the warehouses. With that info, I was able to use Proc Geocode to estimate the latitude/longitude of each warehouse, and plot them on a SAS map (click the map below to see the interactive version with html hover-text over each marker, and links to bring up a Google satellite map of each location):