Why can Google detect my old phone ( gps off ) using android device manager?

[AC Question]

I recently purchased a new lenovo phone. So when i stumbled on Android Device Manager (ADM), I used its locate feature but to no avail because it prompted me to turn on the gps, which i did after and i could locate my phone somewhat accurately. However, myold Samsung S2 was in the list of my devices, so itried to locate it online using ADM too. However, ADM managed to locate my S2 even without the gps turned on. And it was almost as accurate as the Lenovo. Can someone explain this? Im confused.

 

[cpaight]

Did the S2 have GPS on when you used to use it? Has it been in the same place ever since you switched phones? It could be that ADM just has a cached location from the last time GPS was on.