How to develop a Google Maps mashup
In my previous post I noted that Google Maps has released Version 2 of its API. In this post I thought I'd talk more about how you can start developing with Google Maps. Mashups are all the rage, so if you're a developer or just like to remix things - now's a good time to jump in and build one!
The easiest way to get content for your mashup is to use APIs (Application Programming Interface) from companies such as Google, Amazon or eBay. That is, big companies that offer a reliable and large data set via documented API hooks into their systems. You can also use RSS from companies like craigslist.
APIs come in a range of levels, from simple to complex. Maps APIs are generally regarded as being the easiest to work with. Other APIs are more sophisticated - such as those dealing with e-commerce transactions.
Most API providers require that you sign up for access and often APIs will come with restrictions. The Google Maps API for example requires that you have a Google Account. To use the API, Google issues you with an alphanumeric key “that is uniquely associated with your Google Account and the URL of your service.” Up till recently, it came with a limit of 50,000 page views per day - but that's now been lifted.
So what does the Google Maps API do? Essentially it lets you embed Google Maps in your mashup, free of charge. It has a Javascript library associated with it and an authentication model via the developer key. It uses a JavaScript object model and uses the REST protocol for data transport. The data formats are XML and VML for polylines. John Musser (as always) has more details.
When you get to the point of coding a Google Maps mashup using the official API, start with Google’s documentation. It offers many examples and reference material.
Also Joshua Siler wrote an article entitled ‘How to add a Google Map to any web page in less than 10 minutes’, which is a quick and easy introduction to developing a mashup using the Google Maps API. And it comes with a very fine example of a Google Maps mashup: Exploration Age, which is described as a site where you can “catalog your personal travels with your own Virtual Pin Map.”
So all you developers out there wondering what all the fuss is about 'web 2.0', spend an hour or so building a Google Maps mashup - and you'll soon find out.