Location QR Code Generator for Addresses and Map Pins

What goes into the query

The code carries one line of text: a Google Maps search URL, with your value written into the query parameter and URL-encoded so spaces and commas survive the trip. That form comes from the Google Maps URI and URL API, where a single query accepts a place name, a street address or a coordinate pair, and it is the reason the same printed square behaves the same on an iPhone and on an Android phone.

Which of your inputs becomes the query depends on how the two coordinate fields parse. When latitude and longitude both look like numbers, the query is written as the pair, "12.9716,77.5947", and the address field is not used at all. When either coordinate field is blank, or holds anything that is not a plain number, the address string takes over as the query and Maps decides what it matches.

The check is on shape, not on sense. A latitude of 95 passes the number test and gets encoded happily, and Maps will do something odd with it at the other end. So the pair has to be right before you print: correct hemispheres, a minus sign for anything west of Greenwich, and latitude first, because a swapped pair still produces a valid-looking pin, just on the wrong side of the world.

Why a Maps URL and not a geo: link

There is a tidier option on paper. RFC 6068 defines the geo URI scheme, so a coordinate can be written as geo:12.9716,77.5947 with no web address attached, and that is what a lot of location code generators emit. It is shorter, it is a real standard, and on Android the camera hands it to Maps or a navigation app without complaint.

The problem is the iPhone. Apple camera software has never treated a geo link the way Android does, so an iPhone user at your sign can end up staring at a string of numbers instead of a map. The Maps search URL is an ordinary link, so both platforms open it in a browser or the Maps app and land on the same pin. That is the trade this tool makes: guaranteed behaviour on both platforms, at the cost of a longer payload and a denser pattern.

The other half of the trade is connectivity. A Maps URL needs a data connection to resolve, while a geo hand-off can be picked up by an offline map app. For most signage that difference never shows, because a phone that scans a code is a phone with a signal. In a car park basement, a rural trailhead or a basement office, print the address and the coordinates in plain text under the code as well, so the sign still works when the network does not.

How much precision a pin needs

Coordinates are a way of promising accuracy, and the number of decimal places is the promise. The grid is roughly this: one decimal place is about eleven kilometres, two is about 1.1 km, three is about 110 m, four is about 11 m, five is about 1.1 m and six is about eleven centimetres. The rule of thumb holds near mid latitudes, where the distance covered by a degree of longitude is closest to the textbook figure.

• Copy coordinates out of the Maps place page rather than reading them off a handset, because the app has already done the rounding for you.
• For a postal address, four decimals on a nearby pin usually beats an exact coordinate of the wrong entrance, so check which door you are pointing at.
• Extra decimals cost characters, and characters cost density. Stop at the precision you can defend.

Where location codes earn their keep

• Estate agent boards and open-house cards, where the postcode alone drops people at the wrong end of the street.
• Market stalls, food trucks and popup counters that have no fixed postal address but do have a permanent GPS position.
• Delivery and pickup points: the gate that is not the address, the loading bay behind the shop, the farm track entrance.
• Wedding and event stationery, so guests find the correct entrance at a large hall or an estate with several drives.
• Trailheads, cemetery plots, advertising posters and parking bays, anywhere a description is longer than a scan.