GPS scavenger hunt app

GPS scavenger hunts: how location-verified tasks work

How does a GPS-verified task work in Roadblocked?

When you write a task, you choose whether it can be done anywhere or only at a fixed location. For a location-based task you set the spot on an OpenStreetMap map and pick a radius between 10 metres and 5 kilometres (the default is 100 m). From then on:

• The phone checks first. When a player opens the task, the browser asks for their position and compares it to the pin. The submit button only appears once they’re inside the radius.
• The server checks again. The position is sent along with the submission and re-checked on the server, so a team can’t skip the walk by tampering with the page.
• Players see how far off they are. If they’re outside the radius, the task tells them their distance and the required radius, with a Try again button. If the phone is only sharing an approximate location, players get a hint explaining that and how to switch precise location on.
• Most task types can be pinned. A photo, quiz or secret-code task can require being on site. The check-in type goes further: arriving is the task, and it’s graded automatically.
• Everyone sees the map. Players see task pins and their own position live, and you can split the playing field into zones. As the organizer you get a live map of where groups are moving.

Tasks can also stay open, to be completed from anywhere. Mixing both is usually the best design: GPS for the places that matter, open tasks for everything in between.

What is a GPS scavenger hunt good for?

• City tours. Pin landmarks, viewpoints and hidden corners, and pair each with a photo or trivia task. See the outdoor city tour ideas.
• Campus orientation. Check-ins at the library, the cafeteria and the student services desk make sure new students have actually found them, not just read about them.
• School field trips. Keep groups within a park, a museum quarter or an old town, with questions they can only answer by looking around. More in the outdoor school ideas.
• Team events. A route around the office block turns an offsite into a race. See the team building scavenger hunt guide and the outdoor corporate ideas.

Need tasks to fill the map with? The free scavenger hunt idea generator gives you ideas by event type and setting, without signing up.

How big should the GPS radius be?

Phone GPS is good, not perfect. A position that’s off by a few dozen metres is normal, and it gets worse in some places. Pick the radius for the spot, not one number for the whole game:

• Open ground (parks, squares, beaches): a radius of a few dozen metres is usually enough. The 10 m minimum is very strict for a phone.
• Between tall buildings (“urban canyons”): signal bounces off walls, so give a noticeably bigger radius – around the 100 m default is a sensible start.
• Large landmarks: centre the pin on the area teams will actually stand in, and make the radius cover all of it, not just the middle.
• Tasks close together: overlapping circles are fine, but if two pins sit within each other’s radius, both will unlock from one spot.

Walk the route before the day, open a test game on your own phone and try each pin. It’s the quickest way to find the spot that needs a bigger circle. The pre-game checklist covers the rest of the test run.

Does GPS work indoors?

Badly. Walls and ceilings weaken and reflect the signal, so an indoor position can drift far enough to put a team in the wrong room – or the wrong building. For indoor stops, either use a generous radius that covers the whole building or skip GPS and confirm the visit another way:

• QR scan: print a code and hang it at the spot. Scanning it completes the task and can reveal a clue. QR tasks don’t use GPS at all.
• Secret code: write a word on a sign or have a staff member hand it out; teams type it in and it’s graded automatically.
• Photo: ask for a picture that could only be taken at that spot, and judge it in the grading queue.

The trade-offs are covered in more depth in indoor vs. outdoor scavenger hunts and task types and when to use each.

What should players know before they start?

• Allow location when asked. The browser asks for permission the first time. If someone taps Block, the task page explains how to re-enable it from the address bar’s site settings – but it’s faster to tell everyone up front.
• Turn on precise location. Some phones share only an approximate position per site, which can make a team look farther away than they are.
• Charge up. The play page reads GPS while it’s open, and a long outdoor hunt with the screen on uses battery. Ask teams to start fully charged, and bring a power bank for a long route.
• Give the first fix a moment. Finding a position can take a few seconds outdoors and longer indoors or with a weak signal.

Is a GPS scavenger hunt OK to run with a class?

A few facts teachers usually ask about:

• No student accounts. Groups join with a link in the phone browser. There’s nothing to install and no sign-up for players.
• Location is tied to a group, not a person. Positions are linked to an anonymous group and a random device identifier, never to a name. Tracking needs the browser’s location permission and stops when the play page is closed.
• You stay in control of the data. Location history and submissions are deleted together with the group or game they belong to, and you can delete games, groups and submissions yourself.
• Adults run it. Where players are minors, the game should be organized and supervised by a responsible adult.

The full details are in the privacy policy. For task ideas, see the indoor school ideas and how to size groups in how big should your teams be.

What happens after a team submits?

Auto-graded tasks (check-in, secret code, multiple choice, action) score immediately. Photos, videos and free-text answers land in your grading queue the moment they’re sent; you award points from your phone and the leaderboard updates live, ready to put on a TV for the finale. Tips for keeping that fast are in how to grade a scavenger hunt fairly and fast.