I'm going on holiday and downloaded some offline maps app, I was just wondering if the location services (GPS?) work without any data i.e Wifi for 3G on the iPad 2?
Granted you have an iPad with GPS chip, the location services do work, but the iPad may take a bit longer to acquire the correct position. Apple explains this in a nice support article.
Location services are based on GPS, you don't need Internet connection.
Note that wifi-only iPads don't have GPS.
Location services will only work without a data connection on the iPad WiFi+3G model. The WiFi-only version doesn't include GPS, the user’s longitude and latitude are determined based on their proximity to known Wi-Fi networks on these devices. So, location services on this model depend on the connection to a WiFi network.
The WiFi+3G models have a GPS chip and therefore work without any 3G or WiFi connection but the initial locking can take much longer in this circumstance. This is why Apple uses Assisted GPS, which uses proximity to cellular towers and WiFi networks first to get the location locking faster.