iPhone如何在使用它们进行位置估算时学习新的WiFi位置

I know the iPhone can and does use WiFi proximity to get approximate location. This obviously only can occur when some database in the sky knows the approximate location of that WiFi hotspot. My question is how do hotspots get into that db? Is it automatically added whenever the iPhone has a reasonably accurate GPS position and detects the WiFi or is there some manual or programatic way of adding hotspots?I know the iPhone can and does use WiFi proximi