Is it possible to scan WiFi access points without turning on WiFi?
Starting from Android 4.3 JellyBean, it's possible to scan WiFi access points even if the WiFi is off. It's called &quot;Scanning always available&quot;
From PCMag.com,

As those who have taken a spin around the Android 4.3 ROM have noticed, Google has made a change to devices' Wi-Fi settings in Android 4.3.
&quot;To improve location accuracy and for other purposes, Google and other apps may scan for nearby networks, even when Wi-Fi is off,&quot; describes Google.

If your device is Android 4.3 or newer, you can enable it from Settings - Wi-Fi - Advanced Wi-Fi - Scanning always available.

Fire up the Settings app and tap your finger on the Wireless and Networks option. Tap on the Wi-Fi option, and then tap on the Overflow button on your phone's screen (the triple-dots icon). When this submenu pops up, tap your finger on the Advanced option. From there, you'll want to make sure to check the &quot;Scanning always available&quot; option if you want to participate in the new Android 4.3 feature. Otherwise, if it's checked, you need merely to uncheck it to ensure that &quot;Wi-Fi off&quot; really means &quot;Wi-Fi off.&quot;