QR Codes are two dimensional bar codes that can be used to store web addresses and other data in a form that can be quickly accessed by a mobile phone. Anyone with a camera phone equipped with the correct reader software can scan the QR Code and the phone's browser will automatically load the programmed URL. In this way locations in the real world can be linked to their on-line presence and, of course, to Google Maps.
Semapedia connects Wikipedia articles with real world locations. To create a QR Code for a Wikipedia article you just need to enter the article's web address and Semapedia creates a PDF containing the QR Code that links to the article.
If you post the QR Code up at its physical location you will have helped hyperlink the world. Now when anyone visits the location they can point their mobile phone at the code and immediately be taken to the relvant Wikipedia article.
Semapedia has a Google Map of locations that have been hyperlinked in the real world. Each tag contains the name and the date of the tagger and a photo showing the QR Code posted on its location.
QRMap is a great tool for creating QR Codes for a Google Map centred on any location. You can then use the code to direct mobile phone users to a Google Static Map of your location. For example a night-club could put the QR Code on a flyer so potential customers could quickly access a map of the club via their mobile phones.
To create the QR Code all you have to do is centre the QRmap on a location and press the envelope at the top of the screen. QRMap then creates an e-mail with a tiny URL to a web address where you can find your QR Code. The QR Code can then be cut and pasted into any document.
QR Code Mapplet
The QR Code Mapplet lets registered users create a Google Map with an embedded QR Code. It is possible therefore to create a map that users can scan to get directions to a business, to get the contact details of a business on their phone, or to visit a mobile website or mobile blog.
If users point their phones at the embedded QR Code they can also create a bookmark of a mobile website or mobile blog on their phones or note down an address on the mobile phone, just as they would using a pen and a paper.
Google Chart API
The Google Chart API is a good place to get started if you want to know how to create QR Codes.