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Google Maps Mashups with Google Mapplets, Michael Young, Appress 2008 This short book is an introduction to creating Google Mapplets - small web gadgets that are hosted by Google and use Google Maps. As well as introducing mapplets, the book builds a mashup application that uses scripts hosted on a separate website to poll and parse data for the mapplet. The book assumes some beginner-level knowledge of JavaScript and PHP. Some knowledge of Google Maps and XML is probably also helpful. If you have a high level of expertise in these areas, then you can probably work out how to use mapplets effectively without the need for this book. However, the book could serve as a helpful get-you-started book for those with more limited knowledge.
Appress have published this book in their firstPress series, which they describe as "...your source for understanding cutting-edge technology. Short, highly focused, and written by experts, Apress's firstPress books save you time and effort." and "They cover the concepts and techniques that will keep you ahead of the technology curve". So the emphasis is to get something concise but informative that is published quickly. The result, in this case, is a thin book that almost gleefully trumpets its "115 pages" on the front cover! Combined with a relatively large font that is easy to read, the effect is of a book that is also quick to read. This could be good if you want to get up to speed on a subject quickly, but it also results in a high cost per page and hints at limited content. So what is in the book? It is split into two roughly equal parts. The first introduces Google mapplets. It shows you how to create them, how to perform simple operations such as adding markers, and how to use external data feeds.
It also has a useful section on the differences between the JavaScript Google Maps API and Mapplets. This could have been included at the beginning, because this was my main question for the first third of the book. However, by including it after the basic introduction results in a more valuable comparison. The second part creates a functional mashup that plots band venues and upcoming appearances on a map. This covers a lot of the more practical ground, eg. finding a feed of appearances, parsing it, geocoding it, and creating a geocoded feed. This is implemented as a PHP script running on your own publically visible webserver. All this takes two chapters and forty pages - only about 15 pages at the end implement the Mapplet side of things. Despite this, it is a useful introduction as to how a proper mapplet mashup might be implemented. The application's data processing (capture raw feed, parse it, and geocode it) is too computationally intensive for the Mapplet's JavaScript. Instead it is parsed on a cron job on a remote server to produce a feed that the Mapplet can easily access. So why would you want to buy this book and work with Mapplets instead of the more traditional Google Maps API?
As well as the fact that Mapplets work as gadgets alongside Google Maps, they are hosted by Google. This takes care of a lot of the housekeeping chores - eg. having an API identifier, checking the browser is Google Maps compatible, etc. On the downside, Mapplets communicate with Google Maps asynchronously, and obtaining data from an external server (ie. the developer's) is more complicated. The book includes a lot of code snippets and some complete listings. Many of the complete listings were missing but can be downloaded from the Appress site. It would have been useful to have all of them printed, so that the text's discussion could be seen in an implemented context. A number of times I was left thinking "I know those two lines of code do X, but how do they relate to the rest of the script?" The book is a quick read, and is a good way to very quickly introduce yourself to Mapplets. It does rely on some JavaScript and PHP experience, but not a huge amount. It would suit a relative beginner. Experts in JavaScript, PHP and mashups could get up to speed on Mapplets from the documentation alone.
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