Bitcoin ATM Manufacturers
The easiest way to buy bitcoins is by using a bitcoin ATM. Some Bitcoin machines also support sell bitcoin operations. There are many companies that produce bitcoin ATMs. This page contains the list of bitcoin ATM manufacturers with the number of ATM isntallations in the world for every bitcoin ATM type. You can find the current state of the bitcoin ATM market share on the chart.
Bitcoin to cash and cash to bitcoin service providers
There are many ways to buy and sell bitcoins for cash without using a bitcoin ATM. There are many providers doing this. Some are using existing networks of traditional bank ATMs, or existing network of mobile payment terminals, others use retail chains and allow to buy bitcoins via cashier desk etc. The ones who provide their locations over API are listed on our map as well (mark "Other services" checkbox to get them displayed):