SCHOOLGIRLS have been warned against using a mobile app which allows other users to pinpoint their exact location on a map.

Safety fears have prompted teachers at two grammar schools to contact parents about the new Snap Maps update on Snapchat.

At Parkstone Grammar in Poole, Jez Graves, assistant head teacher and designated safeguarding lead, said: "In order to maintain their safety we would recommend that students switch this feature off to ensure that their location is kept private from other users on this platform."

And Anna Collins, deputy head teacher at Bournemouth School for Girls, said: "As ever, we remain concerned about ensuring the safety of girls online both in and out of school.

"It has come to our attention that Snapchat released an update that will impact on all users. The update now includes a map which plots all users of Snapchat, and it can be zoomed in to and locations of users clearly identified."

Snapchat is a picture and video app used by millions of people all over the world.

Pictures and videos can be sent which then self-destruct within a few seconds of being viewed.

The temporary nature of the pictures was originally thought to encourage sexting but studies have revealed the app, used mainly by teenagers, is primarily used for humorous exchanges of pictures.

Use of the new Snap Maps means a person can be traced to a specific building. There are fears that it allows others to build up a picture of someone's life and where they are at specific times and dates.

Both schools are urging students to choose the setting Ghost Mode so no one can see their location.

How can I switch off Snap Maps location sharing?

1. When in photo-taking mode, pinch the screen to open Snap Map.

2. Touch the settings cog in the top right corner of the screen.

3. Tap ‘Ghost Mode’ to switch off location sharing.

4. Photos and videos posted to Snapchat's public 'Our Story' will still be discoverable on the map.

What is the difference between 'My Story' and 'Our Story'?

'My Story' is what just your friends see and 'Our Story' is what you choose to submit to Snapchat and can potentially be made public.

Childnet.com has issued the following advice:

Sharing location can be a risky thing to do. Our tips for location sharing are:

• Only share your location with people you know in person. Never share your location with strangers.

• Don’t add contacts to Snapchat if you don’t know them in person.

• Regularly review your settings and take an active decision about whether you want people to know your location. Remember you can switch this off at any time.

Think about where you’re sharing your location. Location services such as Snap Maps can lead people to your house.

Think about what times you’re on the app and whether these are locations you want to share – if not, then turn this off within your settings.

More information is available at childnet.com/blog/introducing-snap-maps-the-new-location-sharing-feature-in-snapchat